Home

zeta potential manual

1. 2 Click on the square located to the left of the print selection A black check mark will display in the box selected 3 Click on OK to start printing the distributions and or plots The following Print window will display Zeta Potential Software PSS ZLSM 042106 11 06 Page 4 5 ZETA POTENTIAL SOFTWARE Print PR Printer Name KONICA MINOLTA C350 PCL5c v Properties Status Ready Type KONICA MINOLTA C350 PCL5c Where IP 192 168 0 199 Comment Print to file Print range Copies e Al Number of copies 1 lt e Ker Pe QUA co 1 Verify the printer type selected If changes need to be made follow these steps 2 Click on the Down arrow A window of all of the printer brands and types will display Selection of the correct printer driver software depends on the setup of this option 3 Position the highlight bar over the Printer type and model that is currently hooked up to the computer being used 4 Click the mouse once 5 Click on the OK button The Print windows will re display with the printer and type and model selected 6 Position the cursor over the print range desired All will print all data pertinent to the distribution being reviewed Pages will print the range of pages desired Selection will only print those pages desired 7 Position the cursor in the Copies option and type a number for the number of copied desired for the printout The default is
2. Huckel Limit Phase Analysis PALS e E r Time of Sample Pull sec ec Time of Sample Flush s Cancel Temperature This is the temperature that the cell is set to It can be incremented by 0 2 degree step Liguid Viscosity The viscosity of the liguid is directly related to the diffusion of particles suspended in the liguid Using the table provided in Appendix B enter the proper viscosity for the liguid being used Liguid Index of Ref Refraction The index of refraction of the liguid is entered in this field The particles in the liguid are at such low concentrations that you don t want them to have an impact on the measurement Laser Wavelength Input the proper wavelength of the laser being used Please refer to the Wavelength table in Appendix C Zeta Potential Software PSS ZLSM 042106 11 06 Page 4 17 J ZETA POTENTIAL SOFTWARE External Fiber Angle This is the actual angle that the zeta fiber is set to 18 9 degrees for a moving fiber and 18 9 degrees for a fixed cycle Scattering Angle The internal angle taking into account the Fernell band of the glass to air interface 14 7 fixed and 14 7 mobile fiber Phase Analysis PALS The zeta instrument can operate in frequency of Phase analysis mode For 99 9 of the applications Dielectric Constant The ability of the liquid to polarize and it change with ionic strength and pH is reported as the Dielectric Constant The Dielectri
3. Plug the power cable provided into the back of the unit If the unit has the Autodilution feature place the drain line into a waste bucket Apply power to the PC controller Install the Nicomp software package Review the Software section of this manual Apply power to the Nicomp Hardware Installation PSS ZLSM 042106 11 06 Page 3 INITIALIZATION OF SOFTWARE E INITIALIZING Following is the procedure for initializing the Neutral Density ND filter in the 380 ZLS instrument for both zeta potential and particle sizing modes of operation 1 Power up the PC 2 Click on the ZPW388 icon to access the software with no power applied to the 380 ZLS unit The following window displays 9 Correlator is not connected y Setup Correlator Yes No 3 Position the highlight bar over the Setup option of the Tool Bar and click once The following screen displays System Setup x Select Serial Port Multi Angle Option COM1 COMS C Fixed Angle 90 Deg C COM COMB e Multi Angle Square Cell C COM3 COM C Multi amp ngle Round Cell C coM4 COM8 Multi Angle Model 170 Interrupter li 35 deg Flow Pump Change Laser Wavelength nm Intensity Overshoot Factor 1 2 M NICOMP Intens wt Threshold Enable Intensity Monitor Titrator Installed Zeta High E Field Capability organic sample Fixed Zeta Angle Photon Counting Module PMT Only Sizing and Zeta C APD Sizing and PMT Zet
4. 40 20 o DOPPLER FREQENCY DISTRIBUTION 200 100 0 100 200 Freguency Hz gt Sample Reference Sample Frequency 275 26 Hz Reference Frequency 260 28 Hz Cell Current 0 00 mA Frequency Shift 14 98 Hz Ava Mobility 2 13 MU Half Width Mobility Dist er Avg Zeta Potential 28 60 mV Half Width Zeta Pot Dist ann Sample Temperature 23 c Liquid Viscosity 0 933 cPoise Index of Refraction 1 333 Dislectric Constant 78 500 Laser Wavelength 639 0 nm Scattering Angle 14 1 deg E Field Strength 14 00 V CM Channel Width 500 0 uSec Run Time 00 01 35 Appendix A PSS ZLSM 042106 11 06 PageA 5 APPENDIX A MOBILITY DISTRIBUTION FREQUENCY MODE ONLY lot 0510051 REI 80 60 40 20 Particle Sizing Systems Inc Santa Barbara Calif USA MOBILITY DISTRIBUTION Data File C Work in Progress Nicomp ZLS Manual 030806 3802L8 test499 400 13 7 9 11 2 2006 20 10 0 10 20 Mobility M U gt Sample Reference Sample Frequency 275 26 Hz Reference Frequency 260 28 Hz Cell Current 0 00 mA Frequency Shift 14 98 Hz Avg Mobility 2 13 MU Half Width Mobility Dist er Avg Zeta Potential 28 60 mV Half Width Zeta Pot Dist K Sample Temperature 23 c Liquid Visoosity 0 933 cPoise Index of Refraction 1 333 Dielectric Constant 78 500 Laser Wavelength 639 0 nm Scattering Angle 141 deg E Field Strength 14 00 V CM Channel Width 500 0 uSec Run Time 00 01 35 Appendi
5. 0 418 0 402 0 348 0 233 0 222 0 197 0 419 0 358 1 950 1 721 0 887 0 730 19 90 13 35 9 13 4 95 3 30 1 804 1 465 1 219 INDEX REFRACTION 1 558 1 558 1 558 1 415 1 380 1 380 1 380 1 380 1 359 1 359 1 359 1 495 1 495 1 424 1 424 1 424 1 352 1 352 1 325 1 361 1 361 1 538 1 538 1 445 1 445 1 431 1 431 1 431 1 431 1 446 1 371 1 371 1 371 Appendix B PSS ZLSM 042106 11 06 Page B 3 J APPENDIXB SOLVENT n Heptane n Hexadecane n Hexane Isobutyl alcohol Isopentane Isopropyl alcohol Methyl acetate Methyl alcohol Methanol Methyl ethyl ketone M EK Methyl formate Methylene dichloride Nitrobenzene Nitromethane o Nitrotoluene Appendix B PSS ZLSM 042106 11 06 Page B 4 TEMP C 20 25 40 20 20 23 25 40 15 30 20 15 30 20 40 20 25 30 40 15 30 15 25 15 30 15 20 25 20 30 40 VISCOSITY cpoise 0 409 0 386 0 341 3 45 0 326 0 3068 0 294 0 271 4 703 2 876 0 223 2 86 1 77 0 381 0 320 0 597 0 547 0 510 0 456 0 423 0 365 0 360 0 328 0 449 0 393 2 24 2 03 0 620 2 37 1 91 1 63 INDEX REFRACTION 1 388 1 388 1 388 1 433 1 375 1 375 1 375 1 375 1 397 1 397 1 355 1 385 1 385 1 380 1 380 1 326 1 326 1 326 1 326 1 379 1 379 1 346 1 346 1 424 1 424 1 550 1 550 1 380 1 547 1 547 1 547 APPENDIX B SOLVENT m Nitrotoluene p Nitrotoluene n Octane Pentane Propyl a
6. 1040 10 and 1040 11 Radiation Control for Health and Safety Act of 1968 42 U S C 263 As presently constructed this instrument is designated by the Bureau of Radiological Health Class product Exposure to negligible levels of Laser Radiation during normal operation results The two labels below are affixed to the back panel of the Nicomp 380 Autodilute They attest to the above Safety Certification and also establish the place and date of manufacture of the unit THIS EQUIPMENT CONFORMS TO PROVISIONS OF US 21 CFR 1040 10 AND 1040 11 PARTICLE SIZING SYSTEMS 75 Aero Camino Suite B Santa Barbara CA 93117 Tel 805 968 1497 FAX 805 968 0361 MODEL SERIAL NO VOLTS MANUFACTURED MONTH YEAR MADE IN UNITED STATES OF AMERICA Important Read carefully before attempting to operate the Nicomp If the Nicomp is to be used with the Autodilution option then all liguid samples will be introduced into the system by means of a syringe or tube connected to the manual sampling valve that is located on the front panel of the instrument In this case NO entry into the sample holder space will be reguired Alternatively if the Nicomp is to be used without the autodilution option then all liguid samples will be introduced into the light scattering cell using 6 mm disposable glass culture tubes or standard 1 cm cuvettes In this case entry into the sample cell holder space will be reguired General Information PSS ZLSM 04
7. 18 42 73 38 139 05 3 15 42 26 48 138 56 3 14 42 11 58 139 27 3 15 42 33 68 139 56 3 16 42 41 Show Summary The Summary Table displays with the following data SUMMARY TABLE x Print lot 051005ia E Field 14 0 Y cm Cell Current 0 00 mA Run Cycles Time sec Phase rad s Mobility M U Zeta Pot I mY 11 68 139 56 3 16 42 41 Zeta Potential Software PSS ZLSM 042106 11 06 Page 4 32 Ty i J ck x v lt D bi ZETA POTENTIAL SOFTWARE HELP Index Using Help Get System Information About ZPW388 Index The index is a listing of the older keystroke commands that have been replaced by icons buttons and menu choices Using Help Get System Information About ZPW388 About ZPW388 Ed cue ZPW388 Application Version 1 82 Copyright 2003 NICOMP Particle Sizing Systems Santa Barbara California USA Tel 805 968 1497 Fax 805 968 0361 This provides some of the information required when troubleshooting the system such as software version number etc It also provides users with a link to the Particle Sizing Systems website which provides access to a listing of telephones numbers that can be used to call for help Zeta Potential Software PSS ZLSM 042106 11 06 Page 4 33 E a gt S J ZETA POTENTIAL SAMPLE ANALYSIS EZ SAMPLE ANALYSIS 1 To transfer to Zeta Potential Software click on Particle Sizing located on the Tool Bar as seen on th
8. 256 channels 500us ch from which the ELS power spectrum Figure 3 was obtained by FFT Interestingly the zeta potential for these latex particles is observed to decrease when the amount of added SDS surfactant is reduced The latex beads are stabilized during production with a substantial negative charge imparted by an adsorbed layer of anionic surfactant However if this concentrated dispersion is highly diluted some of the surfactant must leave the particle surfaces in order to maintain the low concentration of free surfactant monomers and micelles in the aqueous phase Hence additional anionic surfactant must be added to keep the particles sufficiently charged to avoid aggregation In summary it is evident that the technique of ELS constitutes a powerful tool for the measurement of electrophoretic mobilities and zeta potentials of charged colloidal systems It is especially useful when combined with DLS technology for multi angle high resolution particle size analysis in the same instrument package Zeta Potential Introduction PSS ZLSM 042106 11 06 Page 2 11 Phx HARDWARE INSTALLATION u A INITIAL HARDWARE INSTALLATION t 1 Connect the 25 pin male connector of the cable provided to the port identified on the back of the Nicomp instrument 2 Connect the 9 pin female end of the connector to a serial port on the PC controller Hardware Installation PSS ZLSM 042106 11 06 Page 3 1 HARDWARE INSTALLATION
9. C Liquid Viscosity 0 933 cP Liquid Index of Refraction 1 333 Laser Wavelength 632 8 nm External fiber angle 18 9 degrees Scattering angle 14 7 degrees Phase Analysis PALS Dielectric constant 78 5 Electrode spacing 0 4 cm E field Strength 15 v cm Initial Time Delay 0 sec Smoluchowski Limit Huckel Limit Time of Sample Pull 1 sec Time of Sample Flush 10 sec 3 Click on OK if the entries are correct If they are not position the cursor in the field s that need to be corrected 4 Click once and the correct value s Zeta Potential Sample Analysis PSS ZLSM 042106 11 06 Page 5 2 ZETA POTENTIAL SAMPLE ANALYSIS JUL 5 Prepare the sample cuvet by filling it about 2 3 full with sample 6 The liquid sample level should adjusted so that the top surface of the liquid lies a little bit below the plastic piece that holds the electrodes This will prevent capillary creep of the liquid up the inside surface of the cuvet and onto the outer surface where it can distort the optical quality of the cuvet surface Insert the electrodes and clean the cuvet surface with a lint free wipe 7 Insert the cuvet with electrode assembly into the sample cell holder with the pins of the electrical connector pointed toward the back of the unit Attach the zeta power cable to the plug 8 Close the trap top to the unit Wait for 5 minutes for the sample to temperature equilibrate If the sample does not have a uniform tem
10. COM3 COM Mult Angle Round Cell C C0OM4 COMS C Multi Angle Model 170 Interrupter 1135 deg Flow Pump Change Laser Wavelength nm Intensity Overshoot Factor 1 2 NICOMP Intens Wt Threshold Enable Intensity Monitor Titrator Installed Zeta High E Field Capability organic sample Fixed Zeta Angle Photon Counting Module PMT Only Sizing and Zeta APD Sizing and PMT Zeta 5 Cancel Select Serial Port Four serial ports are provided for setting up communications between the Nicomp and the computer Position the cursor over the desired selection and click on the corresponding circle A black circle will display next to the selection and the parameter will appear in the System Setup menu Multi Angle Option This parameter is used to establish the configuration for the detection of scattered light There are four possible configurations to choose from Zeta Potential Software PSS ZLSM 042106 11 06 Page 4 11 J ZETA POTENTIAL SOFTWARE Fixed Angle 90 Deg Selected when using the basic Nicomp in which the scattering angle is set to 90 degrees Multi Angle Square Cell Selected ifthe Nicomp possesses the multi angle option computer controlled stepper motor 0 9 deg step optical fiber and a square cuvet either normal 1 cm or miniature is used for the sample cell Range 10 170 Multi Angle Round Cell Selected when the Nicomp possesses the multi angle option
11. DLVO theory of colloidal stability provides a reliable analytical framework for estimating the extent of repulsion or attraction between two particles in suspension as a function of their separation The repulsive contribution to the interparticle pair potential depends on the particle charge and size and the concentration of mobile ions The attractive portion depends on the strength of the Van der Waals attractive forces as characterized by the Hamaker coefficient The charged mobile ions in solution distribute themselves between the large particles according to the laws of electrostatics and thermodynamics The ions that carry a charge opposite to that of the colloidal particle surface are attracted preferentially to it Conseguently the electrical potential in the solution Y produced by the charged particle decreases with increasing distance from its surface due to the screening of its electric field by the mobile ions The maximum value of the 7potential P occurs at the surface of the particle The higher the overall salt concentration the steeper the decay in Y with distance from the surface The charged particle surface and the diffuse layer of mostly oppositely charged ions surrounding it comprise the electrical double layer Its thickness is defined as the distance from the particle surface at which the electrical potential Y falls to 1 e of Y and is commonly referred to as the Debye H ckel screening length x For a monovalent
12. EE 3 100 Gi 3 200 3 300 3 400 CECI CELI 3 503 Time sec gt Zeta Potential Software PSS ZLSM 042106 11 06 Page 4 30 ti gt E ZETA POTENTIAL SOFTWARE 4 Phase Shift A critical graph that provides a visual display of the phase shift of the zeta potential measurement over time The numerical results may be seen in the Show Detail ZPW388 Version 1 82 NICOMP Particle Sizing Systems File View Setup Zeta Potential Display Help SR eloo ele eg 313 11 81 el 4 18 Phase Shift rad s PHASE SHIFT HISTORY 155 Run Time hr min sec 0 1 7 150 Scat Intensity 145 X1000 146 ER Count Rate x1000 135 an E Field 14 00 V CM 128 ly g 20 35 50 68 Time sec gt Zeta Potential Measurement Avg Phase Shift Avg Mobility Avg Zeta Potential 139 56 rad s 3 16 M U 42 41 mV E Field 14 00 V CM Cell Current 0 00 mA Printout ID lot 051005ia For Help press F1 Read File 5ia z 400 Zeta Potential Software PSS ZLSM 042106 11 06 Page 4 31 N ZETA POTENTIAL SOFTWARE Show Detail The Zeta Potential Summary Result window display with the following data ZETA POTENTIAL SUMMARY RESULT x Print lot 051005ia E Field 14 0 V cm Cell Current 0 00 mA Time sec Phase rad s Mobility M U Zeta Pot I mY 9 143 94 3 26 43 75 18 139 56 3 16 42 42 28 140 59 3
13. Sample Analysis PSS ZLSM 042106 11 06 Page 5 3 ZETA SAMPLE ANALYSIS TITRATION 27 Zeta Sample Analysis Titration PSS ZLSM 042106 11 06 Page 6 1 A ZETA SAMPLE ANALYSIS TITRATION Zeta Sample Analysis Titration PSS ZLSM 042106 11 06 Page6 2 ZETA SAMPLE ANALYSIS AuTo TITRATION Zeta Sample Analysis Auto Titration PSS ZLSM 042106 11 06 Page7 1 A ZETA SAMPLE ANALYSIS AUTO TITRATION Zeta Sample Analysis Auto Titration PSS ZLSM 042106 11 06 Page 7 2 ALIGNMENT L ALIGNMENT Below is a sketch of the fiber optic assembly and cell holder of the multi angle system utilized in the Nicomp instruments as viewed from the FRONT of the uniit Fiber Optic and Cell Holder Assembly Insert cell holder cyl cell Removeable cell holder lt Thumbscrew DO NOT REMOVE 200 um pinhole Optical Fiber Yipee Fiber optic assembly gt lt Shaft of stepper motor t Optics Plate Stepper Motor Alignment PSS ZLSM 042106 11 06 Page 8 1 ALIGNMENT The procedure for aligning the optical fiber arm assembly follows 1 10 Insert a dilute sample solution e g 260 nm latex in water into the cell holder using a disposable plastic 1cm cuvet Adjust the sample concentration so that the scattering intensity is approximately 200 400KHz From the Control Menu request an external angle of 60 degrees The moveable fiber optic arm will then go to tha
14. and a cylindrical sample cell The true scattering angle is equal to the external angle of the stepper motor arm provided the cell is highly cylindrical and well aligned i e centered on the shaft of the stepper motor Caution Do not use the round cell at any angle except 900 unless you are using an index matched cell Multi Angle Model 170 Designed to be used with the Nicomp 170 Computing Autocorrelator Any value for the actual scattering angle independent of the type of scattering cell used may be entered Interrupter The interrupter angle parameter is only used for the Nicomp units which include the multi angle option The interrupter angle is the reference angle for the moveable arm on the stepper motor which carries the pinhole optical fiber receiver When power is first applied to the Nicomp the internal computer causes the stepper motor arm to rotate until it intersects an optical interrupter The latter defines the reference point or interrupter angle which is approximately 122 4 degrees with respect to the forward direction of the laser beam which defines the zero angle Caution It may differ for other instruments Consult PSS if you experience any problems measuring a size standard Zeta Potential Software PSS ZLSM 042106 11 06 Page 4 12 ZETA POTENTIAL SOFTWARE LE The stepper motor than advances in the opposite direction at 0 9 degrees step until the arm reaches 90 degrees in angle The number
15. light ELS at this angle is collected by OF and transmitted to the PMT detector However in addition a small fraction approx 4 reflected by of the original laser light beam referred to as the local oscillator LO is split off by beam splitter BS1 mirror M2 and directed at a second beam splitter BS2 A small fraction of the LO light wave is reflected by BS2 into the OF pickup where it mixes coherently with the LS wave The resulting coherent superposition of light signals is transmitted to the PMT detector by the optical fiber By analogy to a radio receiver this scheme is referred to as a heterodyne light scattering system Accurate heterodyne detection reguires that the intensity of the LO wave greatly exceed i e 20 1 to 30 1 that of the LS wave with which it is mixed A variable neutral density filter NDF is used to automatically adjust the intensity of the detected ELS wave relative to the intensity of the LO wave Typical intensities expressed as photopulse rates for the two waves are 2 000 4 000 kHz and 100 200 kHz respectively The frequency of the LO wave vo is enormous e g 5 x 10 Hz for red HeNe light compared to the small Doppler shift Av expected in the frequency of the ELS wave Hence it is not feasible to measure directly this miniscule relative change in frequency However the coherent mixing of the two waves at the detector provides the desired result The electronic photopulse signal produced by the PM
16. marking is a mandatory marking on certain products which is reguired if they are placed on the market in the European Economic Area EEA By affixing the CE marking the manufacturer or his representative or the importer assures that that the item meets all the essential reguirements of all applicable EU directives The CE mark is a mandatory European marking for certain product groups to indicate conformity with the essential health and safety reguirements set out in European Directives To permit the use of a CE mark on a product proof that the item meets the relevant reguirements must be documented This has been achieved using an external test house which evaluates our particle size analyzers and its documentation CE originally stood for Communaut Europ enne or Conformit Europeenne French for European Conformity The following label is affixed to the back panel of the AccuSizer SIS to indicate that the instrument has passed CE mark testing and conforms to the European Union Directives for Electromagnetic Compatibility EU EMC CE General Information PSS ZLSM 042106 11 06 Page 1 3 ZETA POTENTIAL THEORY gt MN v Ki gt INTRODUCTION There has been increasing interest recently in techniques that provide a quantitative measure of the charge on colloidal particles in liquid suspension Electrophoretic light scattering ELS which can measure the zeta potential of these particles is one such techniq
17. of steps depends on the value of the interrupter angle Any subsequent changes in angle are made from th 90 degree resting angle If the moveable arm becomes misaligned the resting angle may differ from 90 degrees The resulting error can easily be eliminated by resetting the value of the interrupter angle If the resting angle is too small e g 88 degrees the interrupter angle must be decreased by the appropriate amount Flow Pump The flow pump parameter indicates whether the Nicomp contains a flow pump which is required for the Autodilution option The flow pump may be operated manually or by automatic computer control in Autodilution mode Deactivate the flow pump by selecting this option Drop in Cells Use of the flow pump must be suspended when using a drop in cell to take a measurement If it is not flooding in the unit will occur causing major damage to the instrument Change Laser Wavelength The appropriate laser wavelength for the type of external laser being used Is entered using this option The default wavelength is 632 8 nm which is required for the basic Nicomp with internal 5 mW HeNe laser LASER WAVELENGTH RLD 5 MW HENE 632 5 nm RLD 12 MW HENE 635 nm RLD 35 MW HENE 639 nm RLD 50 MW HENE 664 nm RLD 100 MW HENE 664 nm GLD 20 MW HENE 532 nm GLD 50 MW HENE 532 nm GLD 100 MW HENE 532 nm Zeta Potential Software PSS ZLSM 042106 11 06 Page 4 13 J ZETA POTENTIAL S
18. order to achieve a uniform electric field where the scattered light is collected and also to reduce the applied voltage needed to achieve significant values of field strength The lower voltage reduces the amount of Joule heating and resulting convection that can occur at moderately high salt concentrations Hence there is only a relatively small range of angles at which the scattered light can be collected i e not blocked by the electrodes However there is a much more important theoretical consideration which dictates the use of a small scattering angle In addition to being subjected to a constant drift velocity due to imposition of an electric field the particles always experience random walk Brownian motion or diffusion due to random collisions of the surrounding solvent molecules Indeed this is the ever present phenomenon that gives rise to fluctuations in the scattered light intensity which are analyzed by the DLS technique The autocorrelation function of these fluctuations yields the diffusion coefficient of the particles from which the particle diameter can be derived The random motions of the particles due to diffusion also give rise to fluctuating Doppler shifts in the frequency of the light waves scattered by each particle These random shifts are superimposed on the constant shift Av associated with the drift velocity v caused by the applied electric field In the heterodyne light scattering technique which we use for
19. peak on the freguency distribution Select the start measurement icon The instrument will adjust the ND filter until scattering intensities are optimized for the zeta measurement A small window will appear stating this action is taking place If the error sample too concentrated please dilute appears dilute the sample by 50 and attempt the measurement again If the error persists try initializing the ND filter If the zero point on the ND filter has been lost by the software the full range of the filter is no longer available and the instrument assumes that the reason the scattering intensities are too large is due to the sample concentration A window will appear stating that data collection has begun with the E Field off The reference signal is being measured and stored This step takes approximately 1 min The small window towards the bottom of the screen will show the number of cycles and runs to be completed It will also display a count down of the time remaining between runs After the measurement is completed it may be necessary to turn off the E Field manually Check the E Field status on the screen before removing the electrodes Files may be read by clicking on the Read Data icon and searching out the file of interest If multiple samples are to be run one may use the same reference for each and a window at the start of any subseguent measurement will ask Do you want to measure reference Y N Automatic Zeta
20. salt concentration of 1M length is only 3nm while for 0 01M this length increases to 30 nm The zeta potential amp also called the electro kinetic potential is defined as the value of the electrical potential at the shear plane of the particle For typical colloids this point is close to the actual surface of the particle For relatively low concentrations of added salt the zeta potential as measured by ELS should provide a good representation of Y at the surface of the particles In summary if the electrical double layers of a colloidal system overlap i e if x exceeds the average interparticle separation then the system will usually be stable given a moderate amount of charge on the particles However if the concentration of salt ions is high enough to lead to significant shrinkage of the electrical double layers so that they no longer overlap then the value of amp will be important in establishing whether the repulsive electrostatic potential barrier between neighboring particles is high enough to preclude their agglomeration due to short range attractive Van der Waals forces Zeta Potential Introduction PSS ZLSM 042106 11 06 Page 2 2 ZETA POTENTIAL THEORY M v REVIEW OF ELS MOBILITY DOPPLER SHIFT AND ZETA POTENTIAL As its name implies the ELS technique is based on the scattering of light from particles that move in liquid under the influence of an applied electric field The charge
21. the ELS measurement described below the half width T of frequency broadening of the detected scattered light due to Doppler shifting by the diffusing particles is given by r DK 7 where K is the same scattering wave vector used above Eg n 3 and D is the diffusion coefficient of the particles given by the Stokes Einstein relation D kT 3nna 8 where k is Boltzmann s constant and a is the particle diameter The Doppler shift due to electrophoretic mobility decreases with decreasing scattering angle approximately as sin 0 2 Eg n 4a while the freguency broadening due to diffusion also decreases with angle but as the sauare of sin 0 2 Hence the ability of the ELS technigue to measure small freguency shifts associated with low electrophoretic mobilities dictates operation at a relatively small angle It is instructive to compare the extent of frequency broadening T of the scattered light due to random diffusion with the typical range of Doppler shifts Av encountered from Zeta Potential Introduction PSS ZLSM 042106 11 06 Page 2 6 9 ZETA POTENTIAL THEOR i M v De y electrophoretic mobility typically 1 100 Hz We compute the value of T for two different scattering angles 90 used typically for DLS particle size analysis and 14 8 which we use for our zeta potential measurements We assume HeNe laser light water and a temperature of 23 C The value of T is inversely proportional to the par
22. the second set only a single file containing all data for the 60 seconds Chose to store the data on disk or to automatically print after each run Overwriting the file name is not recommended for systems that utilize a current PC since each file is just a few Kilobytes of information and there is room to save many files Select OK and prepare the sample Prepare the sample cuvet by filling it about 2 3 full with sample Automatic Zeta Sample Analysis PSS ZLSM 042106 11 06 Page 5 2 14 15 16 17 18 19 20 21 22 23 AUTOMATIC ZETA SAMPLE ANALYSIS K The liquid sample level should be adjusted so that the top surface of the liquid lies a little bit below the plastic piece that holds the electrodes This will prevent capillary creep of the liquid up the inside surface of the cuvet and onto the outer surface where it can distort the optical quality of the cuvet surface Clean the cuvet surface with a lint free wipe Insert the cuvet with electrode assembly into the sample cell holder with the pins of the electrical connector pointed toward the back of the unit Attach the zeta power cable to the plug Close the trap top to the unit Wait for 5 minutes for the sample to temperature equilibrate If the sample does not have a uniform temperature throughout the cuvet currents will disturb the particulate whose scattering the instrument is measuring The most common side effect is a split
23. to aggregation There are several means by which a net electrical charge can be attached to the surface of a colloidal particle For particles that are normally uncharged such as oil droplets in a homogenized aqueous suspension charged molecules can usually be adsorbed onto the particle surface This is most commonly accomplished using an ionic surfactant consisting of a polar head group attached to a hydrocarbon tail The latter being hydrophobic associates with the interior of the uncharged particle while the polar head group resides at the surface in contact with the surrounding water and dissociates thereby imparting a net charge to the oil droplet polystyrene bead etc In other cases the colloidal particles may already carry specific groups that are covalently bound to their surfaces and are ionizable They carry a net positive or negative charge or are neutral depending on the pH of the surrounding aqueous solvent Examples include many well known oxides such as silica alumina titanium dioxide etc For these materials the extent and sign of the surface charge depends on the pH of the solution as well as the pKs of the ionizable groups bound to the particle Zeta Potential Introduction PSS ZLSM 042106 11 06 Page 2 1 dl ZETA POTENTIAL THEORY surface Hence the pH of the suspension will strongly influence the net charge of the colloidal particles and therefore their stability against aggregation The well known
24. used in Particle Sizing mode only and MUST not be turned on when performing a zeta measurement Zeta Potential Software PSS ZLSM 042106 11 06 Page 4 27 J ZETA POTENTIAL SOFTWARE To Particle Sizing Switches over the Particle Sizing menu to perform a particle size analysis Initialize ND Filter Titration Control menu Initialize Titrator Start Titration Measure pH Read Menu File Save Menu File Zeta Potential Software PSS ZLSM 042106 11 06 Page 4 28 ir U EN LA J NI v lt a ZETA POTENTIAL SOFTWARE DISPLAY MENU Zeta Potential History Mobility History Phase Shift History Show Detail Alt S Show Summary Zeta Potential Dist A X2 Scale Change x pH vs Zeta Potential Alt N Zeta Potential History A critical graph that provides a visual display of the stability of the zeta potential measurement over time The numerical results may be seen in the Show Detail Zeta Pot l mV ZETA POTENTIAL HISTORY 30 20 20 60 80 Time sec gt Zeta Potential Software PSS ZLSM 042106 11 06 Page 4 29 E ra gt A d ZETA POTENTIAL SOFTWARE Mobility Distribution A critical graph that provides a visual display of the mobility of the zeta potential measurement over time The numerical results may be seen in the Show Detail Mobility MA MOBILITY HISTORY 2 893 CELI HEH 3 000
25. with precision the alignment which produces the maximum scattered intensity Finally set screw A must be tightened to secure the arm assembly onto the motor shaft One should verify that the scattering intensity remains approximately the same after this screw has been tightened CAUTION Set screw A must NOT be tightened too hard to avoid damage to either the screw or the arm assembly Alignment PSS ZLSM 042106 11 06 Page 8 3 MAINTENANCE L MAINTENANCE If electrodes appear to have noticeable tarnish then they will have to be polished 1 2 Cut a strip of 600 grit wet dry emery paper 4 x 34 Adhere with a glue stick the strip of emery paper to a similar sized metal or wooden strip e g atongue depressor Wet the emery paper and electrode pair with clean water Holding the electrode in one hand and the emery paper in the other rub each surface of the electrode pair below the White Delrin across the emery paper using a back and forth motion Continue until the tarnish is removed Cut a strip of 1200 grit wet dry emery paper 4 x 34 Adhere with glue stick the strip of emery paper to a similar sized metal or wooden strip e g a tongue depressor Wet the emery paper and electrode pair with clean water Holding the electrode in one hand and the emery paper in the other rub each surface of the electrode pair below the Delrin across the emery paper using a back and forth motion Con
26. 0 The multi angle arm with the fiber optic cable will then automatically step toward smaller angles make contact with the reference detector and then move to the default small angle that is reguired for the zeta potential mode of operation 18 9 degrees After the arm has come to rest at a small angle the Zeta Control Menu displays Zeta Control Menu x Menu File C docume 1 donna applic 1 qualcommeudoraattachzpw388 tbl Temperature E E Dielectric Constant 78 5 Liquid Yiscosity oan cPoise Electrode Spacing 0 4 cm Liquid Index of Ref 1333 E Field Strength fho V em Laser Wavelength 6328 Initial Time Delay DI sec External Fiber Angle 18 9 deg fe ec E Lind Scattering Angle 14 7 deg Huckel Limit Phase Analysis PALS e e r Time of Sample Pull sec sec Time of Sample Flush Cancel Initialization of Software PSS ZLSM 042106 11 06 Page 2 4 INITIALIZATION OF SOFTWARE A Note The default value of the angle should be 18 9 degrees in all cases If the default is not 18 9 the user can click in the box and change the value to 19 the system will correctly interpret to mean 18 9 degrees Make all values as above and Click on OK The angle for the zeta potential mode of operation will then change to the desired value of 18 9 degrees This value will then be stored in memory and in the Control menu for future operation It may be necessary to establish that the local osc
27. 0 mV Half Width Zeta Pot Dist Sample Temperature 23 c Liquid Viscosity 0 933 cPoise Index of Refraction 1 333 Dielectric Constant 78 500 Laser Wavelength 639 0 nm Scattering Angle 14 1 deg E Field Strength 14 00 V CM Channel Width 500 0 uSec Run Time 00 01 35 Appendix A PSS ZLSM 042106 11 06 Page A 8 APPENDIX A A ZETA POTENTIAL HISTORY PHASE MODE ONLY Appendix A PSS ZLSM 042106 11 06 PageA 9 A APPENDIX A MOBILITY HISTORY PHASE MODE ONLY Appendix A PSS ZLSM 042106 11 06 Page A 10 APPENDIX A Ei PHASE SHIFT HISTORY PHASE MODE ONLY Appendix A PSS ZLSM 042106 11 06 Page A 11 APPENDIX B SOLVENT Acetaldehyde Acetic Acid Acetone Acetonitrile n Amyl acetate n Amyl alcohol n Amyl ether Aniline Benzaldehyde Benzene Benzonitrile Benzyl Alcohol Benzyl amine Bromoform TEMP C 10 20 15 25 41 59 15 25 41 15 25 30 11 45 15 30 15 15 25 35 25 20 30 40 15 25 30 20 30 25 15 25 VISCOSITY cpoise 0 256 0 220 1 31 1 16 1 00 0 70 0 337 0 316 0 280 0 375 0 345 0 325 1 58 0 805 4 65 2 99 1 188 5 31 3 71 2 71 1 39 0 652 0 564 0 503 1 45 1 24 1 11 5 80 4 65 1 59 2 152 1 89 INDEX REFRACTION 1 332 1 332 1 380 1 380 1 380 1 380 1 357 1 357 1 357 1 346 1 346 1 346 1 400 1 400 1 410 1 410 1 410 1 583 1 583 1 583 1 544 1 498 1 498 1 498 1 526 1 526 1 526 1 538 1 538
28. 1 Select either Inc E Field Strength or Dec E Field Strength to adjust the field The left most cell in the status line bottom of the screen indicates the voltage and current The current should be less than 1mA If not decrease the E Field strength Note If the current is less than 1mA the user may adjust the E Field Strength to a greater value 22 Press C to clear the correlator A small screen displays prompting to clear data Warning K Clear Correlator 23 Select Yes After 20 seconds a black spectrum appears overlaid on the red power spectrum At the bottom of the screen a Zeta Potential Measurement window displays It will contain the degree of freguency shift and the calculated zeta potential 24 Select the Save Data file icon to save a data file when acceptable zeta potential information is obtained The result may look something like the below POWER SPECTRUM Run Time hr min sec 100 0 0 34 80 Ch 1 Data IE x1000 60 22343 Count Rate 40 x1000 1607 a E Field ie R Ee AS 15 00 V CM 200 Sample Frequency Hz gt a Zeta Potential Measurement Sample Frequency Ref Frequency Frequency Shift Mobility Zeta Potential 20 12 Hz 0 00 Hz 20 12 Hz 2 63 M U 35 29 mV Printout ID Zeta Potential Sample Analysis PSS ZLSM 042106 11 06 Page 5 6 lt e AUTOMATIC ZETA SAMPLE ANALYSIS f JA AUTOMATIC ZETA SAMPLE ANALYSIS 1 From the Particle Sizing Menu choos
29. 1 540 1 587 1 587 Appendix B PSS ZLSM 042106 11 06 Page B 1 J APPENDIXB SOLVENT n Butyl acetate n Butyl alcohol Carbon disulfide Carbon tetrachloride Chlorobenzene Chloroform Cyclohexane Cyclohexanol Cyclohexanone Cyclohexene Cyclopentane n Decane N N Dimehtylformamide DMF Appendix B PSS ZLSM 042106 11 06 Page B 2 TEMP C 20 40 20 30 40 20 40 15 20 30 40 15 20 40 20 30 39 15 30 20 30 15 30 13 5 20 13 5 20 25 20 25 VISCOSITY cpoise Ke 563 2 948 2 3 1 782 0 363 0 330 1 038 0 969 0 843 0 739 0 900 0 799 0 631 0 58 0 514 0 500 1 06 0 82 68 0 41 1 2 45 1 80 0 696 0 66 0 493 0 920 0 853 0 84 0 80 INDEX REFRACTION 1 372 1 372 1 400 1 400 1 400 1 628 1 628 1 459 1 459 1 459 1 459 1 523 1 523 1 523 1 444 1 444 1 444 1 426 1 426 1 456 1 456 1 450 1 450 1 445 1 445 1 404 1 409 1 409 1 427 1 427 APPENDIX B SOLVENT Dimehtylaniline n Dodecane Ethyl Acetate Ethyl alcohol Ethanol Ethyl benzene Ethyl bromide Ethyl ether Ethyl formate Ethylene bromide Ethylene dichloride Ethylene glycol Formamide Formic acid TEMP C 20 30 40 25 15 20 25 30 20 30 40 15 30 15 20 30 20 25 40 15 30 17 20 15 30 20 30 40 60 25 20 30 40 VISCOSITY cpoise 1 41 1 17 1 04 1 35 0 473 0 455 0 441 0 400 1 200 1 003 0 834 0 697 0 581
30. 2106 11 06 Page 1 2 GENERAL INFORMATION JA Access to the sample cell holder necessary for inserting or removing a sample cell is provided by a sguare opening at the front left corner of the top cover of the instrument A rectangular dust cover with handle and three thumb screws are provided to keep the scattering cell and internal optical components free of excessive amounts of dust when the unit is not in use for extended periods of time and to prevent the laser light from scattering outside the unit during operation During normal operation this cover can be secured with one screw and swung to one side to provide easy access to the cell holder It can be swung shut during operation to keep out stray room light and keep in beam light being scattered by the particles During operation of the NICOMP Autodilute Submicron Particle Sizer the Top Cover of the unit Must Remain Closed i e attached to the cabinet by means of the 3 screws provided The Warning label on the cover warns of the possible exposure to the laser beam a minimum of 5 milliwatts 632 8 nm wavelength if the top cover is removed for any reason while power is applied to the unit Important Any attempt to remove the front panel while the instrument is in operation may result in possible Direct Exposure to Dangerous Laser Radiation Also power must be off to the unit if the Autodilution cell is being replaced by the drop in cell CE MARK The CE mark officially CE
31. 6 ZETA POTENTIAL SOFTWARE HA FILE The following provides a brief summary of the File options that are used during the use of the Windows CW388 Software Access of the File options 1 Position the highlight over the FILE option and click once using the mouse The following window of File options displays Read F6 Save FS Save ASCII ALT F5 Print P Print Preview Ctri P Print Setup Exit 2 Position the highlight bar over the desired selection and click once Following is a description of each of the options offered Zeta Potential Software PSS ZLSM 042106 11 06 Page 4 1 R E 4 g gt E i ZETA POTENTIAL SOFTWARE Read A data file that has been stored following a measurement can be retrieved to display the resulting particle size distribution PSD with the desired weighting When this option is selected a list of data files will display in the Read Data File window such as in the example below Read Data File Look in O 030806 380ZLS E ek Be Sia z 400 bts z 400 e Sia z 401 E bts z 401 el Sia z 402 E bts z 402 E 5i z 400 E test499 400 E 5i z 401 E 5i z 402 Fle name Files of type CA Cancel Iw Open as read only 1 Position the highlight bar over the data file of interest and click the mouse once The Zeta Potential History will display Zeta Potential Software PSS ZLSM 042106 11 06 Page 4 2
32. A new file in ASCII format will be created and stored in the Data Directory with the file extension asc If the same file name already exists the following message will appear Save ASCII File A C Work in Progress Nicomp ZLS Manual 030806 380ZLS 103106dh asc already exists Do you want to replace it 2 Click on Yes the existing ASCII file having the same file name will be erased and the new one stored in its place No no new file will be stored Zeta Potential Software PSS ZLSM 042106 11 06 Page 4 4 gt ae e M E 35 gt ZETA POTENTIAL SOFTWARE E Print Printouts of the sample distributions that display on the computer monitor can be achieved using this option Please refer to Appendix A for printout samples 1 Click on the File Window option and position the highlight bar over the Print option and click The following Printout Option window will display PRINTOUT OPTION Print Detail Print Summary Result for phase mode only Print Time History for frequency mode only Print Power Spectrum for frequency mode only Print Doppler Frequency Distribution for frequency mode only Print Mobility Distribution for frequency mode only Print Zeta Potential Distribution Print Ph vs Zeta Potential Dist Print Zeta Potential History for phase mode only Print Mobility History for phase mode only Print Phase Shift History for phase mode only Cancel
33. DIX A L TIME HISTORY FREQUENCY MODE ONLY Particle Sizing Systems Inc Santa Barbara Calif USA lot 0510051 Data File C Work in Progress Nicomp ZLS Manual 030806 3802L8 test499 400 13 7 9 11 2 2006 Zeta Por mV TIME HISTORY 30 20 40 60 20 12 30 50 70 96 Time sec gt Sample Reference Sample Freguency 275 26 Hz Reference Freguency 260 29 Hz Cell Current 0 00 mA Frequency Shift 14 98 Hz Avg Mobility 213 MU Half Width Mobility Dist Avg Zeta Potential 28 60 mV Half Width Zeta Pot l Dist Sample Temperature 23 c Liquid Viscosity 0 933 cPoise Index of Refraction 1 333 Dielectric Constant 78 500 Laser Wavelength 639 0 nm Scattering Angle 14 1 deg E Field Strength 14 00 V CM Channel Width 500 0 uSec Run Time 00 01 35 Appendix A PSS ZLSM 042106 11 06 PageA 3 J APPENDIX A POWER SPECTRUM FREQUENCY MODE ONLY POWER SPECTRUM 80 60 40 20 0 200 100 Frequency Hz gt Appendix A PSS ZLSM 042106 11 06 Page A 4 Run Time hr min sec 0 0 34 Ch 1 Data x1 000 22343 Count Rate ST 000 1607 E Field 15 00 V CM Sample Reference 3 E JA APPENDIX A L DOPPLER FREQUENCY DISTRIBUTION FREQUENCY MODE ONLY lot 0510051 Particle Sizing Systems Inc Santa Barbara Calif USA Data File C Work in Progress Nicomp ZLS Manual 030806 3902L81test499 400 13 7 9 11 2 2006 REI 80 60
34. ION a nnam manaamaan aan nana aa A ri aaron ne iraani ta oaran atiae 7 PH VS ZETA POTENTIAL DISTRIBUTION 2uuuuu2220000un00000nnnnnnunnnnnununnnnnnnnnnnnnnnnnnnnannnnnnnannnnnnn 8 ZETA POTENTIAL HISTORY PHASE MODE ONLY 2uuu2u0u2000 2000 nun nun ann nun nnn nun ENEE en 9 MOBILITY HISTORY PHASE MODE ONLY occcccccncccncccnncnnonennnnnnnnnnnnnnnnnnnnnnnnnonnnnnnenennnnnnnnnns 10 PHASE SHIFT HISTORY PHASE MODE ONLY cccccccccnoconoconenonennnnnnnnnnnnonnnnnnonennnnnnnnnnnnnnnnns 11 Table of Contents PSS ZLSM 042106 11 06 Page ii GENERAL INFORMATION JA REGISTRATION Please register your software by taking a moment to fill out the registration page provided In keeping with our promise we can easily provide two years of free software upgrades Just call us if you need information about our other products or information about upgrading your existing system TECHNICAL SUPPORT If technical support is needed please contact one of the following offices Particle Sizing Systems 8203 Kristel Circle Port Richey FL 34668 Tel 727 846 0866 Fax 727 846 0865 Or Particle Sizing Systems 201 Woolston Drive Ste 1 C Morrisville PA 19067 Tel 215 428 3424 Fax 215 428 3429 General Information PSS ZLSM 042106 11 06 Page 1 1 J GENERAL INFORMATION SAFETY CONSIDERATIONS The NICOMP and Autodiluter Submicron Particle Sizer is certified to conform to the applicable requirements of 21 CFR Subchapter J
35. MLD mm S e 3 eier JA 177 O gt r I A Er o gt N N Incident Laser Beam Vector Diagram gt K Figure 1 Relationship between the incident laser beam and scattered light wave for ELS vector diagram relating these to the scattering wave vector K and particle velocity v Zeta Potential Introduction PSS ZLSM 042106 11 06 Page 2 4 ZETA POTENTIAL THEORY 5 gt gt MS v Ki The Doppler shift Av in the frequency of the scattered light is easily computed from Figure 1 and Eg ns 2 and 3 Av K v 2r cos 0 2 2nv A sin 6 2 cos 0 2 4a Use of a common trigonometric identity reduces this to Av nv A sin O 4b Finally substitution of Eq n 1 into the above equation allows the electrophoretic mobility u to be computed from the measured Doppler shift Av for a given applied electric field strength E u Ag n sin 0 1 E Av 5 It is useful to attach some typical numbers to the above formula For the instrument recently developed by the authors the NICOMP 380 ZLS Particle Size Zeta Potential Analyzer the relevant parameters for Eq n 5 are Ao 0 6328 um HeNe laser n 1 33 water and 0 14 8 degrees In this case Eq n 5 reduces to u M U 1 867 1 E Av Finally the value of the mean zeta potential amp is obtained from the electrophoretic mobility u If the concentration of mobile ions in solution is sufficiently high that the th
36. N J mi t v ee DEE y Se ZETA POTENTIAL SOFTWARE Save This option is used throughout the ZPW388 software whenever a data file is to be saved To access this option 1 Position the highlight bar over the File option and click the mouse once 2 Position the highlight bar over the Save As option and click the mouse once The following screen will display Save Data File Save in CO 030806 380ZLS O e Ely E Sia z 400 E bts z 400 E Sia z 401 E bts 2 401 E Sia z 402 E bts 2 402 3 Si z 400 Sj test499 400 i Si z 401 E Si z 402 Save as type 0 v Cancel Save ASCII Use this option to save the data collected for a particular sample to an ASCII file format The data can then be imported to a spreadsheet program for presentation To create new files in standard ASCII format to export data files into other software packages e g spreadsheets for manipulation of the original data follow these steps 1 Select a data file 2 Position the highlight bar over the File option and click once 3 Position the highlight bar over the Save ASCII File option using the mouse and click once the following window displays Zeta Potential Software PSS ZLSM 042106 11 06 Page 4 3 gt K ES 7 ZETA POTENTIAL SOFTWARE Save ASCII File Save in 2 Nicomp ZLS Manual D e 2 rz Ely Berme Fe Save astype Ir sec D Cancel 1 Type in the desired file name
37. NICOMP 380 ZLS User Manual Particle Sizing Systems Inc Particle Sizing Systems makes every effort to ensure that this document is correct However due to Particle Sizing Systems policy of continual product development we are unable to guarantee the accuracy of this or any other document after the date of publication We therefore disclaim all liability for any changes errors or omissions after the date of publication No reproduction or transmission of any part of this publication is allowed without express written permission of Particle Sizing Systems Inc DOCUMENT CHANGE HISTORY 77 Date Description of Document Revision of New Release Number Review 11 11 06 New Document 01 Particle Sizing Systems Nicomp 380 Zeta Potential User Manual PSS ZLSM 042106 11 06 REGISTRATION iii ge 1 TECHNICAL SUPPOR Tunnel 1 SAFETY CONSIDERATIONS 0d dada 2 E UE 3 INTRODUCTION Te oe a te 1 ELECTROSTATIC REPULSIONS AND COLLOIDAL STABILITY nuunuunnnnunununnnununnnnnnnnnnnnnnnnnnnnannnn 1 REVIEW OF ELS MOBILITY DOPPLER SHIFT AND ZETA POTENTIAL 0ssssseseeeeeeeeceeeenens 3 INSTRUMENT DESIGN CAPABILITY FOR BOTH ELS AND DLG cccsssseseeeeeeeeeeeeeneeneneeees 7 REPRESENTATIVE ELS RESULTS cconcncccconcnncononanacononanarononanarcnnananrronananacona nana rnnananaranananas 10 INITIAL HARDWARE INSTALLATION zuzuunnnnnnunnnnnnnnnnnnnnununnnnnnnnnnnnnnnnnnnnnnnnnnannnnnnnannnnnnnannnnnnnnn 1 dl RK e 1 BEE
38. OFTWARE Intensity Overshoot Factor When the intensity falls to approximately the Intensity Setpoint which is set in the Conrol Menu the pump in the Nicomp will halt thereby stopping the flow of fresh diluent The Intensity Overshoot Factor compensates for the variation found in the bearing of different pumps NICOMP Intens Wt Threshold This option eliminates any part of a distribution when the entire intensity contributed by that peak is less than the value specified in this item Enable Intensity Monitor Provides intensity as a function of time For kinetics studies this option allows the user to monitor and record the intensity vs time for a given solution Titrator Installed optional There is an optional autotitrator for producing electronic curves in the zeta potential world It allows for the titration of a sample with buffer and reports the values at each pH buffer point Zeta High E Field Capability organic sample Organic dispersions that do not conduct electricity well require the high voltage option to create an electronic field between the electrodes to monitor the zeta potential of the suspension Fixed Zeta Angle The zeta interrupted comes in two flavors a fixed zeta fiber at 19 external and 14 7 internal or a multi angle zeta fiber which is included with the multi angle system to perform a zeta measurement in the formal direction of 19 external and 14 7 at the internal angle Zeta
39. Potential Software PSS ZLSM 042106 11 06 Page 4 14 ZETA POTENTIAL SOFTWARE LE Photon Counting Module PMT Only Sizing and Zeta APD Sizing and PMT Zeta High gain detector offers 7 times the gain of a standard PMT for sizing small nanoparticles 0 1 10 nm or low concentration colloidal solutions Maximum Count Rate An APD can be damaged by exposing it to high levels of scattered light This value automatically shuts down the APD if the value of the scattering intensity exceeds the value in the table to avoid damage Normally this value is around 1000Khz Zeta Potential Software PSS ZLSM 042106 11 06 Page 4 15 Sa MN v gt ZETA POTENTIAL SOFTWARE ZETA POTENTIAL MENU Control Menu F3 Auto Print Save Menu F2 Read Reference File Clear Data E Control Buttons F8 To Particle Sizing ESC Initialize ND Filter Alt Ctrl 1 Read Menu File F7 Save Menu File Ctrl F7 Zeta Potential Software PSS ZLSM 042106 11 06 Page 4 16 S i J Pe x v lt D bi ZETA POTENTIAL SOFTWARE Control Menu Zeta Control Menu x Menu File C docume 1 donna applic 1 qualcomm eudora attach zpw388 tbl Temperature 23 E Dielectric Constant 785 Liquid Viscosity 0 933 cPoise Electrode Spacing 0 4 cm Liquid Index of Ref 1 333 E Field Strength 10 V om Laser Wavelength nin Initial Time Delay lo sec External Fiber Angle 18 9 deg GG Smoluchowski Limit Scattering Angle 14 7 deg
40. RE EE EE 6 RIES E R s ees 1 Read assa maaten antamaan A 2 Oae A Ta A Ja AN KN ate a he n AE n de 3 et VC IEN 3 Prats saan eco aa Amk a etal EE hte Se 5 A ee el Se ede m t kin si SE O 7 PENIS E 8 MIEW MENU uta aaa 9 Toobi acct awe ssa em a aed eA ea PAI das Md dan deni dedi eel 9 Status Barra Te ee se ee een ee 10 G10C Kosista ASENN NA se Lt ota RN tetas tat ahd ea a 10 EIB ee ele EECe ele Seite ENEE Eed EE Sue DEE EE de Ee Eer der Ate EE 11 Select Serial PO kat a ae EEEE i Ta ELO an ar en nen 11 Multi Anale Opi OD en energie 11 age 12 Fow Pump es 13 Change Laser Wavelen gth essen de 13 Intensity Overshoot Factor a ea cra 14 NICOMP Intens Wt Threshold o occcccnnncccccnnoncninonincnanonancnanonanonononann aan ana ana aaaaaaa 14 Enable Intensity Monitor erte ee 14 Titrator Installed niara ae eei eA kaan akan akan AREA EAA LEANEN 14 Zeta High E Field Capability organic sample 14 Fixed Zeta Angler ee elek 14 Photon Counting Module en ee Nee ee 15 ZETA POTENTIAL MENU ee aaar e anna de SSEENEEE RENE SEENEN 16 Gontrol Men net ech ee NTT MIN Nasan esse ee 17 Auto Print Save Menu 20 Store Data op Disk en ENEE 21 Overwrile Old Fla ii od 22 Print Result a e ais 22 PrINTOULORION nee indices 22 Set to Reference EE 23 Mark Unmark Sample Freq na de end al 24 Table of Content PSS ZLSM 042106 11 06 Page i TABLE OF CONTENTS Abs Rel Power Speetrum creme are dace Sead 25 leet Dalaran
41. T 3 Inc Scattering Intensity ALT 2 Dec Scattering Intensity ALT 1 E Field ON y E Field OFF CNTL Inc E Field Strenath CNTL I Dec E Field Strength CNTL D Inc Scatt Angle by 0 9 Deg CNTL F4 Dec Scatt Angle by 0 9 Deg CNTL F5 APD Power On CNTL F6 APD Power Off CNTL F Reference Beam ON Reference Beam OFF Control of power to the reference beam is maintained when selecting these options Inc Scattering Intensity Dec Scattering Intensity The ND filter can be rotated in the desired direction to increase or decrease the scattering intensity of 120 kHz by selecting these options This position of the ND will be stored in memory so that when the unit returns to Particle Sizing mode the ND wheel will return to this position E Field ON E Field OFF Power to the E Field is controlled using this option Inc E Field Strength Dec E Field Strength The E Field strength is set in the Control menu but may be adjusted by increasing and decreasing the field before or during a measurement using these options Zeta Potential Software PSS ZLSM 042106 11 06 Page 4 26 ZETA POTENTIAL SOFTWARE LE Inc Scatt Angle by 0 9 Deg Dec Scatt Angle by 0 9 Deg The scattering angle may be changed manually using the stepper motor controlling the fiber optic This is only to be changed when using the Particle Sizing mode of the software not the Zeta Potential option APD Power On APD Power Off The APD is
42. T detector contains a component which effectively oscillates at the beat note or difference frequency between the two individual optical frequencies All that is required to determine Av is to measure the frequency power spectrum of the PMT output signal In practice however the overall accuracy or signal noise ratio of the measurement can be greatly improved by shifting the frequency range of interest from zero Hz DC to some convenient frequency away from the influence of common sources of electronic noise and drift which are especially prevalent at very low frequencies Hence it is useful to add an arbitrary fixed frequency to the existing frequency of the LO wave This added shift is conveniently accomplished by using the Doppler effect once again A piezoelectric translator PZT attached to mirror M2 is driven at some arbitrary frequency vpzr 260 Hz in our case The frequency of the LO wave is shifted upward to Vo Vpzt The beat note which therefore appears on the output of the PMT detector representing the difference in frequencies of the ELS and LO waves is similarly translated upward to vpzr Av The electrophoretic mobility will therefore be manifested as a frequency shift Av with respect to vpzr Proper design and synchronization of the electronic waveforms that drive the cell electrode voltage and PZT device allow the sign as well as the magnitude of the frequency shift to be determined Zeta Potential Int
43. a Cancel Initializing of Software PSS ZLSM 042106 11 06 Page 2 1 J INITIALIZATION OF SOFTWARE Select the correct serial port In most cases this will be Serial Port Com 1 Click on the Multi Angle Sguare Cell option Click on OK The system defaults to the Particle Sizing operating mode Remove the top cover of the 380 ZLS unit and remove any Velcro or elastic bands that restrain the moveable arm holding the optical fiber DO NOT apply power to the 380 ZLS unit until the arm has been unrestrained and is free to rotate stepper motor shaft It is important to note that the arm MUST be restrained again prior to shipping the unit In order to avoid damaging the optical fiber and or losing the optical alignment that was set up at the factory Prepare a dilute slightly turbid agueous suspension of submicron polystyrene latex suggestion 265 nm by mixing 1 drop of latex with DI water and pipette some of it into one of the sguare plastic cuvets which are supplied with the unit Fill the cuvet to about 2 3 capacity The laser beam will enter the cuvet above the outside bottom Place the sample cuvet into the sample holder It may be necessary to remove the drop in block or flow thru cell to accommodate this Apply power to the 380 ZLS unit The moveable arm should automatically step toward the smaller angles until it reaches the reference interrupter at which point it should reverse direction and commenc
44. ady Type KONICA MINOLTA C350 PCL5c Where IP 192 168 0 199 Comment Paper Orientation Size Letter 8 1 2x 11 inch x Portrait Source Auto v Landscape co Printer The printer that is used for the majority of the printing when using the computer controller In some cases this may be a black and white printer Allows for the selection of another printer type such as a color printer for printing out color distributions Paper The paper sizes available depend on the model printer that is being used By clicking on the down arrow located to the right of the Size window a listing of the available paper sizes for the computer being used displays The default is set to Letter 8 1 2 x 11 since most printers accommodate for this size The default for this option is set to Portable Sheet Feeder however some printers have two paper trays for printing The source of the paper feed depends on the model of printer being used Orientation The data distributions will display vertically on the paper selected or horizontally on the paper selected Zeta Potential Software PSS ZLSM 042106 11 06 Page 4 8 ZETA POTENTIAL SOFTWARE L VIEW MENU Click on View in the Main Window in order to pull down the View Menu In the default condition both the Tool bar containing the icons near the top of the Main Window and the Status Bar located at the bottom of the Window are activated checked They should rema
45. ar all past information from the correlator if performing multiple measurements or allow the information to accumulate No Cycles The number of files saved to illustrate a measurement In one run a user can set multiple save cycles Time per Data Save The time of each cycle of saved data Example If of cycles 2 and time per 30 sec or of cycles 1 and time per 60sec the total measurement time for both conditions will be 60 seconds In the first set of conditions there will be 2 files saved with increasing extension numbers each 30 seconds worth of data in the second set only a single file containing all data for the 60 seconds Store Data on Disk This option may be set to automatically save data during a sample run Zeta Potential Software PSS ZLSM 042106 11 06 Page 4 21 ZETA POTENTIAL SOFTWARE Overwrite Old File Allows the user to overwrite old files This option is very dangerous to use since new data can overwrite old data Print Result Automatic printing at the end of a sample cycle can be performed when this option is selected Printout Option Automatic generation of the following reports may be performed provided the report type is checked Samples of the reports can be seen in Appendix A Zeta Potential Software PSS ZLSM 042106 11 06 Page 4 22 Set to Reference ZETA POTENTIAL SOFTWARE I JA a E E Sets the power spectrum as seen currently on the screen to the reference sig
46. c Constant for DI water is 78 5 The Dielectric Constant is one of the variables used in the calculation of zeta from mobility Electrode Spacing This value is always set as 0 4 cm It is the physical distance between the electrodes E Field Strength The E Field Strength can be set in the control menu but can also be adjusted using the icons to increase and decrease the E Field during or before a measurement Smoluchowski Limit Refers to a condition of high salt where there is screening and Ko 1 Zeta Potential Software PSS ZLSM 042106 11 06 Page 4 18 ZETA POTENTIAL SOFTWARE LE Huckel Limit Refers to a condition of a low salt where the conductivity of the solution is low and the Ko 3 2 Initial Time Delay A time delay at the start of a zeta measurement to allow the dispersion to reach equilibrium Time of Sample Pull and Time of Sample Flush Refers to those systems that have the zeta flow through cell in tritration A special option that is available as a standalone feature or as part of and autotitrator It is the for the auto titrator Zeta Potential Software PSS ZLSM 042106 11 06 Page 4 19 i i PKU v Wu ZETA POTENTIAL SOFTWARE Auto Print Save Menu Zeta Auto Print Save Menu Menu File C docume 1 donnaapplic 1 qualcomm eudora attach zpw3 Data Directory C docume 1 donna applic 1 qualcorr y Browse File Name test 0 Printout ID Sample o Auto Operation Op
47. cetate n Propyl alcohol 1 1 2 2 Tetrachloroethan Toluene Trichlorethane o Xylene m Xylene p Xylene TEMP C 20 30 40 60 20 40 20 20 40 20 30 40 15 20 30 40 20 16 20 40 15 20 40 16 20 40 VISCOSITY INDEX cpoise REFRACTION 2 33 1 545 1 77 1 545 1 60 1 545 1 204 1 533 0 542 1 395 0 433 1 395 0 240 1 357 0 59 1 382 0 44 1 382 2 256 1 385 1 72 1 385 1 405 1 385 1 844 1 494 0 590 1 494 0 526 1 494 0 471 1 494 1 20 1 438 0 876 1 506 0 810 1 506 0 627 1 506 0 650 1 495 0 620 1 495 0 497 1 495 0 696 1 493 0 648 1 493 0 513 1 493 Appendix B PSS ZLSM 042106 11 06 Page B 5 APPENDIX C LASER WAVELENGTHS The appropriate laser wavelength for the type of external laser being used is displayed in this table LASER WAVELENGTH RLD 5 MW HENE 632 5 nm RLD 12 MW HENE 635 nm RLD 35 MW HENE 639 nm RLD 50 MW HENE 664 nm RLD 100 MW HENE 664 nm GLD 20 MW HENE 532 nm GLD 50 MW HENE 532 nm GLD 100 MW HENE 532 nm Appendix C PSS ZLSM 042106 11 06 PageC 1
48. d particles quickly reach a constant terminal velocity v proportional to the magnitude of the field E The proportionality constant u defines the electrophoretic mobility v uE 1 The units of electric field are V cm and therefore the units of u are cm s V cm cm Vsec Because typical velocities are so small it is useful to express u in terms of the mobility unit M U um s V cm which eguals 10 cm s V cm The moving particles scatter the incident light at a frequency vs which is Doppler shifted with respect to the incident frequency vo The extent and sign of the Doppler shift in frequency Av depends on the velocity of the particle the wavelength of the incident light beam in the liguid medium and the angle or scattering The relationship between these guantities is given simply by 2nAv K ev 2 where K is the scattering wave vector familiar from the theory of DLS The magnitude of K is given by K 47N o sin 0 2 3 where A is the wavelength of the incident light beam in vacuum n the refractive index of the solvent and 0 the angle at which the scattered light is detected The relationship between the electric field and particle velocity vectors the incident wave vector k and the scattered wave vector ks is summarized in Figure 1 Zeta Potential Introduction PSS ZLSM 042106 11 06 Page 2 3 ZETA POTENTIAL THEORY Scattered Light C gt m Sn D N Co N rad tay
49. e To Zeta Potential and the following screen will appear Zeta Control Menu x Menu File C Documents and Settings Donna4pplication Temperature 3 E Dielectric Constant s5 Liquid Viscosity oa cPoise Electrode Spacing jos cm Liquid Index of Ref am E Field Strength TEM Y cm Laser Wavelength 6328 ET Initial Time Delay o sec External Fiber Angle 18 9 deg Smoluchowski Limit Scattering Angle 14 7 deg Huckel Limit Phase Analysis PALS e r Time of Sample Pull sec ec Time of Sample Flush s Cancel 2 Setvalues as indicated in the above 3 Fromthe Zeta Potential Menu choose Auto Print Save Menu and the following screen will appear Zeta Auto Print Save Menu Menu File CAD ocuments and Settings D onna Application Data Directory CADATA06 Data Browse File Name test 0 Printout ID Caption has 80 chracters available for sample description Auto Operation Options No Runs li Time between run E 0 sec Clear correlator on the end of each cycle No Cycles 2 Time per Data Save 30 sec J Store Data on Disk F Overwrite Old File I Print Result Printout Option Cancel Automatic Zeta Sample Analysis PSS ZLSM 042106 11 06 Page 5 1 10 11 12 13 J AUTOMATIC ZETA SAMPLE ANALYSIS Specify a place to store the data collected Data should never be stored to the root C directory From within the Browse function you can create a new folde
50. e following screen s ZPW388 Version 1 82 NICOMP Particle Sizing Systems File View Setup EUGENE Display Weighting Help Elsa ale Control Menu F3 y 2 lalea AutoPrint SaveMenu F2 NICOMP Input Menu I Read Menu File F7 Save Menu File Ctrl F7 Control Buttons F8 To Zeta Potential Alt Z Change Graph Color Alt Ctrl B Initialize ND Filter Alt Ctrl 1 2 Position the highlight bar over the To Zeta Potential option and click once The fiber optic arm can be heard to move from 90 degrees to 19 degrees The following window will display ZPW388 Windows 2 J To Zeta Potential Measurement Yes No Zeta Potential Sample Analysis PSS ZLSM 042106 11 06 Page 5 1 ZETA POTENTIAL SAMPLE ANALYSIS The Zeta Control Menu will appear at the bottom of the screen Zeta Control Menu x Menu File C Documents and Settings Donna Spplication Temperature 3 E Dielectric Constant 785 Liquid Wiscosity 0 933 cPoise Electrode Spacing 04 cm Liquid Index of Ref m E Field Strength 15 W em Laser Wavelenath 632 8 E Initial Time Delay fo sec External Fiber Angle hss deg Ze Smoluchowski Limit Scattering Angle 14 7 deg Huckel Limit Phase Analysis PALS e e e Time of Sample Pull sec sec Time of Sample Flush OK Cancel DE The entries should read as displayed in the following table Temperature 23
51. e stepping toward larger angles If the ZPW388 software is set to Particle Sizing mode the arm will come to rest at the default scattering angle for this mode 90 degrees Press ALT CTRL I simultaneously to initialize the neutral density filter The variable neutral density ND filter should be observed to rotate automatically toward progressively lower amounts of filtering thereby allowing the intensity of the laser beam which passes through the filter to become progressively brighter The firmware system will then detect the edge of the ND filter where the filtering reaches a maximum ND 3 0 units where the attenuation of the beam is greatest approximately 1000 1 The ND filter will then advance slightly further and stop so that the attenuation is approximately maximum The software designates this as ND position 0 The neutral density filter can be moved a total of 255 increments after initialization ND 3 is at position zero and ND 0 is at position 255 From this automatic sequence the system will have found and stored in memory the location of the edge of the ND filter so that all future positions of the filter can be remembered relative to that reference location It should be noted that this ND filter reference location will be stored in the configuration file ZPW388 CFG which will be Initialization of Software PSS ZLSM 042106 11 06 Page 2 2 14 INITIALIZATION OF SOFTWARE created in the same direc
52. ee A Ee 25 Set Zeta Pot l Min Max oocccconccccccnococononnnccnnnnnanonononnconononocononnnncannnnoncnnnanonancnn nana naninnns 25 To Particle SIZING sus eine 28 maliza ND Filer teste En Heine sale 28 Titration Control menu 28 Intialize TIIA LON scott dd tidad s 28 Start o ra orita 28 Me amp sure pH 2a eege een 28 Read Men File iii Haha 28 Save Menu File tceiseti tots ege ee ae 28 DISPLAY MENU cocoa cid tee ER sabes ege SEA i 29 Zeta Potential Sto santi dios 29 Mobility Distribution tos ee II 30 Phase SRT enaa coves cnet rola ei ee ee 31 SHOW Summary aiii ee Eile 32 SAMPLE ANALYSIS SEIBERERTRERFERFHFRTEERETRTEFTNSFRTNELRRNERRETERERRIELTETLEEETEFFEFNSFRERTTELHEFBESEERROERETERFEFFTEERTTSEEE 1 AUTOMATIC ZETA SAMPLE ANALYSIS zuuuuununnnnunnnnunnununnnununnnnnnnunnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn nen 1 ALIGNMENT EE 1 MAINTENANCE CN 1 DISPOSABLE GUVETS via un ven ns Eed ENEE aa 1 IT d TUE 1 SUMMARY RESULT PHASE MODE ONLY u2uuu2u002000 20 nn nn nun ann nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn 2 TIME HISTORY FREQUENCY MODE ONLY uuu2uu02u0n Run ann nun nun nun nun anna nnmnnn nnmnnn nn 3 POWER SPECTRUM FREQUENCY MODE ONLY uuuu22200a000000nnn0nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnen 4 DOPPLER FREQUENCY DISTRIBUTION FREQUENCY MODE ONLY uaazuaaauaan0nnn0nnnnnnnnnnnnnnnnnn 5 MOBILITY DISTRIBUTION FREQUENCY MODE ONLY aouuuuuuuuuuu muu a muu un aan taan aan aan aan ruuna annan 6 ZETA POTENTIAL DISTRIBUT
53. fact that about 4 of the impinging reference beam will be reflected by the silica window into the optical fiber The only remaining problem is the fact that proper alignment of the reference beam with respect to the scattered light signal at the fiber entrance is normally difficult to achieve However this alignment reguirement is conveniently relaxed by using a diffuser to randomize the arriving reference beam This is the reason why a small piece of frosted plastic has been mounted close to the optical mixer in the path of the arriving reference beam One can see the reference beam when the cover is off the instrument when the reference beam on icon is clicked The shutter that blocks the reference beam during normal sizing operation of the instrument will move and the PEM will start to vibrate One can always ensure that the measurement is progressing by the sound this PEM makes Upon installation of the instrument a PSS representative will optimize the alignment by carefully adjusting the thumbscrews located on the two dimensional tilting stage on which is mounted the PEM unit There are not many reasons that the user will have to readjust this alignment In any case the tilting stage should be adjusted in order to produce a total detected intensity of approximately 2000 4000 kHz Any value higher than 4000 kHz should be avoided by slightly de tuning the tilt stage Initialization of Software PSS ZLSM 042106 11 06 Page 2
54. g of the instrument In general this should be the case Unfortunately there is no obvious way for the user to determine whether the arm fiber assembly has moved slightly up or down with respect to the line source of scattered light in the sample cuvet Any gross misalignment of the arm fiber is of course easy to determine from the fact that the level of scattered light intensity is below levels that are normally achieved and expected It is perhaps a good idea to optimize the vertical alignment during the initial setup of the instrument described in a separate section However this procedure should be carried out by a trained PSS service representative Initializing of Software PSS ZLSM 042106 11 06 Page 2 3 INITIALIZATION OF SOFTWARE After the rotation ofthe ND filter has been adjusted to produce the desired typical level of scattering intensity in the Particle Sizing mode of operation Close the Control Buttons window one is now ready to switch to the Zeta Potential mode of operation 15 Position the highlight bar over the Particle Sizing option of the Tool Bar and click once The particle sizing menu re displays see Screen 3 16 Position the highlight bar over the To Zeta Potential option of the pull down menu and click once Answer Yes to the window that asks to move to Zeta Potential measurement After this choice has been made the ND filter will rotate automatically to the location of maximum attenuation position
55. h respect to the line source of light scattering within the sample cuvet In order to improve the alignment the arm must therefore be RAISED Remove the sample cuvet and reinsert the Allen wrench into the cap of screw B The short arm at the end of the wrench can be used like the hand of a clock Alignment PSS ZLSM 042106 11 06 Page 8 2 11 12 13 14 15 ALIGNMENT L Align the wrench at the start so that its hand points away from the front panel i e approx at 12 00 on a clock dial Rotate the wrench CLOCKWISE by 1 4 turn so that the hand points to approx 3 00 This has the effect of RAISING the fiber arm by approx 3 40 or 0 075 Reinsert the sample in the cell holder and check the scattering intensity It should either be unchanged or somewhat higher than the previous value Repeat the operation above as many times as necessary in order to maximize the scattered light signal If the value reaches or exceeds 1000 kHz further dilute the sample suspension to avoid saturating the PMT signal or damaging the detector Of course one typically cannot locate the position that produces the maximum intensity unless the maximum has been exceeded with screw B rotated too far in the clockwise direction Hence one must then rotate the screw COUNTER CLOCKWISE by approx 1 4 to 1 3 turn so that one can go backwards and repeat the earlier operation of carefully RAISING the fiber arm in order to locate
56. ickness of the electrical double layer x is small compared to the mean diameter of the particles a i e ka gt gt 1 then the Smoluchowski approximation applies In this case amp is related in a simple linear way to u amp nwe 6 where n is the viscosity and e the dielectric constant of the solvent In the opposite limit of ion screening known as the H ckel limit where xa lt lt 1 the electrical double layers of neighboring particles overlap significantly In this case the right hand side of Eg n 6 is multiplied by 3 2 For intermediate values of xa an analytical approximation is needed in order to estimate the value of amp from u As expected Eq n 4b the magnitude of the Doppler shift is proportional to the component of the velocity vector lying along the direction of detected scattered light ks proportional to sin 6 Hence it would appear that the measured Doppler shift Av can be increased simply by increasing the angle 0 of detection of the scattered light However in practice this is the opposite of what is required to optimize an ELS measurement for reasons that are both practical and theoretical Zeta Potential Introduction PSS ZLSM 042106 11 06 Page 2 5 dl ZETA POTENTIAL THEORY The practical requirement for small angles is related to the geometrical constraints imposed by the electrodes immersed in the sample solution The parallel electrodes must be relatively closely spaced typ 2 4 mm in
57. ied field of 10V cm The frequency scale has been offset by the modulation frequency of the LO wave vpzt 260Hz which shifts the reference peak to zero Hz The center of the ELS peak is shifted by 19 3Hz with respect to the reference peak corresponding to an electrophoretic mobility u of 3 61 M U or a zeta potential of 48 8mV assuming the Smoluchowski limit The ELS peak is broadened significantly indicating a range of mobilities or zeta potentials rather than a single value Figure 4 shows the ACF from which the shifted ELS peak in Figure 3 was obtained by FFT This measurement was made using 256 channels and a channel width of 500us As expected the ACF resembles a smoothly decaying oscillating function with a freguency corresponding to the mean freguency shift of the ELS wave relative to the LO wave in this case 260 19 3 240 7Hz The characteristic decay time of the envelope of the oscillatory function is inversely proportional to the width of the ELS peak This width depends on the range of amp values Zeta Potential Introduction PSS ZLSM 042106 11 06 Page 2 10 E gt E j ZETA POTENTIAL THEORY 77 gt as well as normal diffusion broadening Eg n 7 inversely related to the mean particle diameter Eq n 8 The broadening due to diffusion alone can be inferred from the width of the unshifted reference peak Channel Width CuS gt Figure 4 Heterodyne autocorrelation function
58. illator LO or reference light beam is properly aligned with respect to the optical fiber carried by the moveable arm Initializing of Software PSS ZLSM 042106 11 06 Page 2 5 INITIALIZATION OF SOFTWARE Reference Beam This reference beam is created by the clear silica beam splitter that lies in the path of the laser beam before it enters the focusing lens mirror assembly near the sample cell holder The incident laser beam is partially reflected by the silica window thereby creating a secondary beam with an intensity about 4 of the intensity of the main laser beam This secondary beam impinges on a miniature mirror attached to a piezoelectric modulator PEM which vibrates at a frequency of approximately 260 4 Hz This beam is then redirected toward an optical mixer i e beam splitter located in front of the moveable arm optical assembly A second clear silica window serves as the optical mixer located between the source of the light scattering in the cell holder and the input of the optical fiber It is oriented at a 45 degree angle with respect to the axis of the fiber which is pointed toward the approximate center of the sample cuvet Scattered light originating from the sample is able to reach the input of the optical fiber with only 4 reflected away The reference light beam coming from the PEM on the other hand can also be mixed with the scattered light signal as it enters the fiber by virtue of the
59. in activated v Tool Bar v Status Bar Clock When the user enters the Zeta mode there are a number of menus and options that change from the regular sizing software Only those differences are listed here Toolbar Increase the scattering intensity by moving the ND filter Decrease the scattering intensity by moving the ND filter K Apply the E field LC Turn OFF the E field E Increase the E Field strength E Decrease the E Field strength 4 ILE Apply the Reference Beam 4 Turn OFF the Reference Beam y Pull sample Zeta Potential Software PSS ZLSM 042106 11 06 Page 4 9 ZETA POTENTIAL SOFTWARE Status Bar The status bar provides pertinent information while running the Nicomp 380 For Help press FI Collecting Data Clock Displays the real time clock that is set up in the windows operating system of the computer This is the clock that is used to date and time stamp the data files that are saved 11 32 59 AM Zeta Potential Software PSS ZLSM 042106 11 06 Page 4 10 HA d Ye ZETA POTENTIAL SOFTWARE lt bi y SETUP The Setup window allows for communication to be established between the Nicomp 380 ZLS and the computer controller System Setup E Select Serial Port Multi Angle Option COM1 COMS C Fixed Angle 90 Deg CC COM COM amp e Mult Angle Square Cell
60. nal The line will turn red to indicate it is now reference Read Reference File A previous stored data file may be accessed and displayed using this option Read Reference File Look in E 081706 zeta v 2 Fk Edy E A06048 0 E A06048 1 A06048 2 E A06048 3 E A06048 4 E A06048p 1 E A06048p 2 E A06048p 3 Zb File name A06048 0 Files of type C EI IV Open as read only Cancel Zeta Potential Software PSS ZLSM 042106 11 06 Page 4 23 L Wl Lu a br J ZETA POTENTIAL SOFTWARE Mark Unmark Sample Freq This option can be used to manually set and obtain parameter information on a peak of the distribution Once selected a crosshair displays on the graph of the power spectrum A value at any point of the sample frequency may be defined by pressing Enter Notice that the Avg Sample Freq value reported on the bottom of the window will change once a new value has been selected Also the Power Spectrum will shift according to the new value selected A red vertical line will display indicating the new sample frequency ZPW388 Version 1 82 NICOMP Particle Sizing Systems Em File View Setup Zeta Potential Display Help SR 2aJe 0 5 2 Sle Sle 313 5111 E e 218 ez REL POWER SPECTRUM Run Time hr min sec 0 1 16 Scat Intensity X1000 221 Count Rate X1000 4264 E Field 10 25 V CM 0 200 Sample Fre
61. or under concentrated sample high scattering always means an over concentrated sample This step assumes the reference beam has been aligned 14 Click on Reference Beam OFF and click Close 15 Press R to obtain a reference spectrum The vibration of the piezoelectric can be heard Within 20 seconds a power spectrum will appear on the screen It should display at 261 Hz 2Hz 16 Continue to collect a reference signal until the 261Hz peak is the most dominant signal in the power spectrum It should be sharp and narrow This should take 60 seconds to achieve and should look like the below Zeta Potential Sample Analysis PSS ZLSM 042106 11 06 Page 5 4 Run Time hrmin sec 0 1 3 Hihii IITTI Sample Reference Sample Frequency Frequency Shift 0 00 Hz 0 00 Hz Frequent 0 00 Hz 17 Select Zeta Potential on the Tool Bar N 1 o Position the highlight bar over the Set to Reference option and click once a satisfactory reference is obtained The spectrum will change to red 1 O Select the E Field ON icon A small window will display prompting if a certain voltage is appropriate 4 gt ZW380 Windows 20 Select Yes if the voltage is set as desired if not click on No and use the Increase and Decrease E Field Strength and turn the E Field back on Zeta Potential Sample Analysis PSS ZLSM 042106 11 06 Page 5 5 ZETA POTENTIAL SAMPLE ANALYSIS 2
62. perature throughout the cuvet currents will disturb the particulate whose scattering the instrument is measuring The most common side effect is a split peak on the frequency distribution 9 Position the highlight bar over the Zeta Potential option and click once 10 Select the Control Buttons option The following window will display with a selection of buttons Zeta Control Buttons X Reference Beam ON ALT 4 Reference Beam OFF ALT 3 Inc Scattering Intensity ALT 2 Dec Scattering Intensity ALT 1 E Field ON y E Field OFF CNTL Inc E Field Strength CNTL I Dec E Field Strength CNTL D Inc Scatt Angle by 0 9 Deg CNTL F4 Dec Scatt Angle by 0 9 Deg CNTL F5 APD Power On CNTL F6 APD Power Off CNTL F _ _ _ _ _ __ _ ____ Close Zeta Potential Sample Analysis PSS ZLSM 042106 11 06 Page 5 3 J ZETA POTENTIAL SAMPLE ANALYSIS 11 Position the highlight bar over the Reference Beam OFF option and click once The motion of the shutter may be heard 12 Adjust the scattering intensity to approximately 75 150kHz by clicking on the Inc Scattering and Dec Scattering Intensity buttons 13 Click on Reference Beam ON after achieving a satisfactory scattering intensity and ensure that the reference scatter value is approximately 10 15 times of that achieved with reference beam off If this is not achieved the sample s concentration should be altered low scattering can mean either an over concentration
63. quency Hz gt Reference Zeta Potential Measurement EI Avg Sample Freg Reference Freg Avg Freg Shift Avg Mobility Avg Zeta Potential 0 00 Hz 0 00 Hz 0 00 Hz 0 00 M U 0 00 mV E Field 10 25 V CM Cell Current 0 00 mA Zeta Potential Software PSS ZLSM 042106 11 06 Page 4 24 ZETA POTENTIAL SOFTWARE E Mark Unmark Reference Freq A crosshair displays on the graph of the power spectrum The user is able to define a new position for the Reference Frequency by pressing the crosshair and then pressing Enter The Reference Frequency will display according to the value selected Abs Rel Power Spectrum Changes the x axis of the power spectrum graph between the reference peak being set to zero and it s absolute value Clear Data The correlator will be cleared of any accumulated data once the option is selected Set Zeta Pot l Min Max Allows the min and max of the x axis to be defined This is helpful when the graph does not show the distribution adequately For instance the peak value is 55 and the scale displayed is 50 0 The peak is off the scale The situation may be remedied by manually setting the x axis of the graph Set Zeta Pot l Maxim EI Maximum 30 Minimum Lon Cancel Zeta Potential Software PSS ZLSM 042106 11 06 Page 4 25 i i PKU v Wu ZETA POTENTIAL SOFTWARE Control Buttons Zeta Control Buttons Reference Beam ON ALT 4 Reference Beam OFF AL
64. r to place data in Printout ID allows a maximum of 80 characters to be entered as a description of the sample that will appear on all printouts Enter the number of runs in No of Runs field By choosing more than 1 run the same sample is used for multiple measurements Enter the Time Between Runs The user may choose to let tne sample rest between each run for a defined period oftime This can be useful in combating Joule heating that may begin to cause convection currents within the sample cell thereby moving particulate around and out of the inspection zone Indicate whether the Correlator should be cleared at the end of each cycle The user may choose to clear all past information from the correlator if performing multiple measurements or allow the information to accumulate This feature is useful when separating sections of data taken over time This will allow the user to take snapshots of what happens to the sample s zeta potential over time with no bias from the past measurements Enter the No of Cycles This number indicates the number of files saved to illustrate a measurement Enter the Time per Data Save The time of each cycle of saved data Example If the of cycles 2 and time per 30 sec or of cycles 1 and time per 60sec the total measurement time for both conditions will be 60 seconds In the first set of conditions there will be 2 files saved with increasing extension numbers each 30 seconds worth of data in
65. roduction PSS ZLSM 042106 11 06 Page 2 8 ZETA POTENTIAL THEORY M v The PMT photocurrent signal consisting of individual photopulses of average frequency 2 000 4 000 kHz is passed to a multichannel digital autocorrelator AC In the case of our NICOMP 380 ZLS instrument the AC uses four fast digital signal processors DSPs with 32 bit architecture operating with an adjustable number of channels and channel width Typical ELS measurements are made using either 256 or 512 channels with 500 us channel The desired frequency shift of the ELS wave relative to the LO wave is obtained by Fourier analysis of the autocorrelation function ACF of the PMT photopulse signal This is accomplished using a fast Fourier transform FFT algorithm which yields the power spectrum PS of the heterodyne signal ELS LO Finally the electrode assembly can be removed from the disposable sample cuvet and the system used to determine the particle size distribution PSD by dynamic light scattering DLS It in possible to use a modified version of the heterodyne scheme discussed above for zeta potential analysis In this case the PZT modulator must be turned off so that the LO wave is no longer Doppler shifted in frequency However for technical reasons it is preferable to make the DLS measurement using the more conventional homodyne scattering approach in which the LO wave is turned off and only the light scattered from the diff
66. set to one 8 Click on the OK button to start printing Zeta Potential Software PSS ZLSM 042106 11 06 Page 4 6 gt g ZETA POTENTIAL SOFTWARE N Print Preview Allows the printout to be viewed prior to being sent to the printer Following is an example of the window that will display A data file must be accessed prior to using the Print Preview option Print will print the distribution that is being previewed Next Page will advance to the next page of the preview Two Pages will preview two pages of the same file side by side Zoom In provides the ability to zoom into the distribution to examine the fine details of the distribution Close will close this option and return to the CW388 Software Window ZPW388 Version 1 82 NICOMP Particle Sizing Systems Print Med Page Prev Psoe TwoPage Zoomin Zoom Gut Particle Sizing Systems ine Santa Barbara on USA It 0510055 Data File C Work in ProgessiNicomp ZLS Manuah020808 20ZLS Sis z 400 11 14 21 103112006 Zeta Pott mv ZETA POTENTIAL HISTORY Zeta Potential Software PSS ZLSM 042106 11 06 Page 4 7 ZETA POTENTIAL SOFTWARE Print Setup This option allows for the setup of the type of printer to be used the orientation of the printout and the size paper to be used Print Setup Printer Name KONICA MINOLTA C350 PCL5c EI Properties Status Re
67. t angle bringing into better view set screw A which fastens the fiber optic assembly onto the shaft of the stepper motor Move the arm back to 90 degrees approx The exact angle is UNIMPORTANT Using a 3 32 Allen wrench loosen set screw A SLIGHTLY so that the arm assembly is able to move up and down on the motor shaft but not too loosely Remove the sample cuvet from the cell holder Insert the same Allen wrench into the space normally occupied by the cuvet and secure it into the cap of Allen screw B Rotate the screw by approximately one 1 full turn COUNTER CLOCKWISE This will cause the screw to retract approx 0 25 from the end of the motor shaft Press firmly down on the Allen screw arm assembly so that the end of the retracted screw will come into firm contact with the end of the motor shaft Note If set screw A is still too tight the arm assembly may not be free to move downward with respect to the motor shaft Test for this by trying to turn screw B CLOCKWISE by a fraction of turn to determine whether the crew encounters resistance indicating that it is in contact with the end of the motor shaft If necessary set screw A should be loosened a bit more Reinsert the sample cuvet into the cell holder and note carefully the new scattering intensity The value should be lower than the value noted previously because of the substantial misalignment just effected The optical fiber should now be too low wit
68. ticle diameter For a 1000nm T 26 9 Hz at 6 90 but only 0 89 Hz at 0 14 8 For a 100nm the respective values are 269Hz and 8 9Hz while for a 10nm the corresponding values are 2690Hz and 89 3Hz INSTRUMENT DESIGN CAPABILITY FOR BOTH ELS AND DLS A simplified block diagram of our combined particle size and zeta potential analyzer the NICOMP 380 ZLS is shown in Figure 2 The instrument employs a novel design which permits both multi angle particle size analysis by DLS and low angle zeta potential analysis by ELS using a minimum number of optical components A single precision optical fiber collimator together with a high resolution stepper motor 0 9 step is used to implement both the ELS and DLS measurements This design offers scientific flexibility without sacrificing ease of use and reliability PMT Detector Optical Fiber Piezoelectric Mod ulator ato N Se d W N lt KN PA d i Autocorrelator FFT Digital Signal Processor v y Frequency Mode Ay 3 E Phase PALS Mode AQ At at Figure 2 Simplified schematic diagram of the NICOMP 380 ZLS Zeta Potential and Particle Size Analyzer based on ELS and DLS Zeta Potential Introduction PSS ZLSM 042106 11 06 Page 2 7 gt ZETA POTENTIAL THEORY In the ELS mode the optical fiber OF is rotated to an external angle of 19 8 which translates for water into a scattering angle of 14 8 Scattered
69. tinue until a smooth polish is achieved DISPOSABLE CUVETS The supplier for the disposable cuvets is Fischer Scientific The part number is 14 386 21 Maintenance PSS ZLSM 042106 11 06 Page 7 1 APPENDIX A DETAIL Particle Sizing Systems Inc Santa Barbara Calif USA lot 0510051 Data File C Work in Progress Nicomp ZLS Manual 030806 380ZLS test499 400 13 7 9 11 2 2006 E Field 14 0 V cm Cell Current 0 00 mA Freg Shift Hz Rel Intensity Mobility M U Zeta Pot l mV 20 53 1 54 2 92 39 21 18 31 1 75 2 61 34 97 16 09 2 00 2 29 30 73 13 87 2 31 1 97 26 50 11 66 2 70 1 66 22 26 9 44 3 20 1 34 18 02 7 22 3 85 1 03 13 78 5 00 4 71 0 71 9 54 2 78 5 88 0 40 5 31 0 56 7 55 0 08 1 07 1 66 10 00 0 24 3 17 3 88 13 79 0 55 7 41 6 10 20 00 0 87 11 65 8 32 30 77 1 18 15 88 10 54 50 00 1 50 20 12 12 76 80 00 1 81 24 36 14 98 100 00 2 13 28 60 17 20 80 00 2 45 32 84 19 41 50 00 2 76 37 07 21 63 30 77 3 08 41 31 23 85 20 00 3 39 45 55 26 07 13 79 3 71 49 79 28 29 10 00 4 02 54 03 30 51 7 55 4 34 58 26 32 73 5 88 4 66 62 50 34 95 4 71 4 97 66 74 37 12 3 85 5 29 70 98 39 39 3 20 5 60 75 22 41 61 2 70 5 92 79 45 43 83 2 31 6 23 83 69 46 05 2 00 6 55 87 93 48 27 1 75 6 87 92 17 Appendix A PSS ZLSM 042106 11 06 Page A 1 A APPENDIX A SUMMARY RESULT PHASE MODE ONLY Appendix A PSS ZLSM 042106 11 06 Page A 2 at E JA APPEN
70. tions No Runs L Time between run fi 0 sec Clear correlator on the end of each cycle No Cycles 1 Time per Data Save 60 sec Iw Store Data on Disk Overwrite Old File Print Result Printout Option Cancel Data Directory Data should never be stored to the root C directory From within the Browse function you can create a new folder to place data in The File name will also display once defined using the Browse option Caution If the directory has many levels it may cause the program to fail upon saving Go no more than 3 levels deep in data directories when allocating a data directory Printout ID Allows a maximum of 80 characters to be entered as a description This description will appear on all printouts for the sample run Auto Operation Options Allow the user to automate data taking Each task can be done manually using the tool bar icons as well Zeta Potential Software PSS ZLSM 042106 11 06 Page 4 20 ZETA POTENTIAL SOFTWARE LE No of Runs By selecting more than 1 run the user can use the same sample for multiple measurements Time between run The user may choose to let the sample rest between each run for a chosen amount of time This can be useful in combating and Joule heating that may begin to cause convection currents within the sample cell thereby moving particulate around and out of the inspection zone Clear Correlator on the end of each cycle The user may choose to cle
71. tory as ZW380 EXE when one exits from the program The firmware should then run through the initialization procedure automatically as indicated above The initialization procedure can always be initiated manually by pressing ALT CTRL I simultaneously Note that the intensity which arises from the test sample It should be very low since the ND filter is positioned for nearly maximum light beam attenuation The filter must therefore be rotated so that the desired light scattering intensity for sizing is achieved typically 300 400 kHz is recommended for a sample that scatters adequately Click on the Particle Sizing menu and choose Control Buttons The following window displays Control Buttons EI Inc Scattering Intensity ALT 2 Dec Scattering Intensity ALT 1 Inc Scatt Angle by 0 9Deg CNTL F4 Dec Scatt Angle by 0 9 Deg CNTL F5 APD Power On CNTL F6 APD Power Off CNTL F8 The ND filter can then be rotated in the desired direction by clicking repeatedly on Increase or Decrease Scattering Intensity until the desired intensity value of 120 kHz is reached This particular position of the ND filter will then be stored by the system so that whenever the unit is returned to the Particle Sizing mode of operation the ND filter wheel will return to that position Note The preceding discussion presumes that there was no significant change in the vertical alignment of the moveable arm optical fiber during shippin
72. ue It can be implemented immediately following production of colloidal particles as a means of estimating their stability against subsequent aggregation Zeta potential analysis by ELS requires no special expertise it can be performed as effectively in demanding process environments as in traditional laboratory settings Fortunately zeta potential analysis by ELS dovetails nicely in a technological sense with that of particle size analysis by dynamic light scattering DLS Given the ability of an ELS instrument to determine the zeta potential of colloidal particles in a simple and fast way one is no longer limited to predicting the future stability of a colloidal system simply from its particle size distribution PSD The latter provides at best only a single snapshot of the present state of aggregation of the system Such an isolated measurement of the PSD is unable to reliably predict the future rate of aggregation of the particles For this purpose a measurement of the zeta potential is invaluable ELECTROSTATIC REPULSIONS AND COLLOIDAL STABILITY The physical mechanism that is used to stabilize most aqueous colloidal systems is electrostatic repulsion The colloidal particles of interest are charged resulting in their mutual repulsion at extended distances Ideally the repulsive forces are sufficiently strong to prevent the particles from diffusing close to each other where short range Van der Waals attractive forces dominate and lead
73. using particles is detected In the ideal case of uniform size particles the ACF is a simple decaying exponential function with decay time t where I t 2T and T is given by Eg n 7 The particle diameter a is then obtained from Eq n 8 For non trivial distributions including simple log normals and more complex bimodals or skewed unimodals the PSD can be estimated from the ACF using either cumulants analysis or a more sophisticated Laplace transform algorithm The multiangle capability shown in Figure 2 is invaluable for broad PSDs at larger diameters a gt 200nm when there is significant angular dependence of the scattering intensity due to intraparticle Mie scattering Zeta Potential Introduction PSS ZLSM 042106 11 06 Page 2 9 ZETA POTENTIAL THEORY REPRESENTATIVE ELS RESULTS REL POWER SPECTRUM Run Time hr min sec 0 0 34 Ch 1 Data X1 000 22343 Count Rate 1000 1607 E Field 15 00 VICM 200 100 0 100 200 Frequency Hz gt Sample Reference Figure 3 ELS power spectrum obtained for 262 nm polystyrene latex spheres E 10 V cm Figure 3 shows the ELS power spectrum PS obtained for a dilute agueous suspension 5000 1 of 10 stock of polystyrene latex spheres of diameter 262nm with 0 2 added surfactant SDS to ensure full charging of the spheres The peak at the center is the reference PS with zero applied E field the left most ELS peak was obtained with an appl
74. x A PSS ZLSM 042106 11 06 Page A 6 APPENDIXA ED at E ZETA POTENTIAL DISTRIBUTION lot 0510051 REI 80 60 40 20 o 200 Zeta Potential mV gt Sample Sample Freguency Reference Freguency Cell Current Freguency Shift Avg Mobility Half Width Mobility Dist Avg Zeta Potential Half Width Zeta Pot Dist Sample Temperature Liquid Viscosity Index of Refraction Dielectric Constant Laser Wavelength Scattering Angle E Field Strength Channel Width Run Time Particle Sizing Systems Inc Santa Barbara Calif USA Data File C Work in Progress Nicomp ZLS Manual 030806 38021L8 test499 400 13 7 9 11 2 2006 ZETA POTENTIAL DISTRIBUTION 100 o 23 C 0 933 cPoise 1 333 78 500 639 0 nm 14 1 deg 14 00 V CM 500 0 uSec 00 01 35 100 200 Appendix A PSS ZLSM 042106 11 06 Page A 7 APPENDIX A PH vs ZETA POTENTIAL DISTRIBUTION Particle Sizing Systems Inc Santa Barbara Calif USA lot 0510051 Data File C Work in Progress Nicomp ZLS Manual 030806 3802L8 test499 400 13 7 9 11 2 2006 1811 1 91 1 41 1 5 Zeta Potential pH vs Zeta Potential 30 20 20 40 60 20 1 7 10 15 pH gt Sample Reference Sample Frequency 275 26 Hz Reference Frequency 260 28 Hz Cell Current 0 00 mA Frequency Shift 14 98 Hz Avg Mobility 213 MU Half Width Mobility Dist un Avg Zeta Potential 28 6

zeta potential manual

Contents

Download Pdf Manuals

Related Search

Related Contents