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operating manual for the Wescore 5520 Osmometers

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1. Instrument Broken or DamagedO Thermocouple Is S D 2 0 less Check for LooseO TC Screws Yes ReplaceO ThermocoupleO Evaluate SampleD LoadingO Technique Head Verify That YouLl are Using 1000 Standards Is There Visible Contamination Yes No 59 SECTION 5 SOLVING PROBLEMS 5 1 Troubleshooting The following is a detailed presentation of material covered in the Troubleshooting Flowchart This material is indexed to further information found throughout the manual 60 Problem Display is blank There is a large shift in calibration Solution Check to see if power indicator is lit Check to see if power is on Check for power on mains Check fuses see Sections 1 5 and 2 8 Check the display and keyboard connections To avoid the risk of serious injury the display and keyboard connections should only be checked by qualified service personnel Reset instrument by turning off power for 3 seconds Then turn power back on If none of these steps resolves the problem contact your dealer or Wescor for assistance Check the Temperature Drift Scale on the display If the scale indicates that ambient temperature is outside acceptable levels take steps to stabilize the instrument See Section 2 SECTION 5 SOLVING PROBLEMS 5 1 Troubleshooting Problem Solution There is a large Check the freshness of the calibration standards
2. Problem Symptom s Thermocouple Contamination A shift in calibration Error message during calibration or Clean Test Deformed or Flattened Loss of high range readings or Thermocouple precision Broken Thermocouple ERROR message on display or wildly erratic behavior if the connection is intermittent Disconnected TC Head ERROR message on the display Connector Loose TC Head Screws Unstable calibration and erratic readings ERROR message during calibration or Clean Test 65 SECTION 5 SOLVING PROBLEMS 5 2 Common TC Head Problems Problems can often be solved by inspecting and cleaning the TC head 1 Follow the instructions in Section 4 to remove the TC head NOTE To improve temperature stability inside the osmometer leave the access cover in place while the TC head is out of the instrument Carefully inspect the TC head under a micro scope Check for any gross contamination on the thermocouple or thermocouple mount Contamination is a natural consequence of normal use of the osmometer It may also occur inadvertent ly during shipping or set up Contamination changes the linearity of the instrument response first detectable in the lower ranges of osmolality Contamination does not generally degrade precision but depending upon the nature of the contaminating substance this can occur See Section 4 for complete instructions to detect and remove contamination NOTE Contamination can be in
3. Purified Water Liquid Dropper Blow Clean Liquefied Propellant or Equivalent Pressure limited to 20 psig NOTE To remove significant contamination use the Wescor cleaning solution followed by numerous successive rins es with pure water Wescor s cleaning solution is approx imately 8 ammonium hydroxide Concentrated ammoni um hydroxide can be used to remove particularly stub born contamination as described in Section 4 6 Lint or dust particles can usually be removed by simply rinsing with water a number of times Place a waste container close by on the floor Use a cotton swab to remove residue from the surface of the mount surrounding the thermo couple CAUTION Do not contact the thermocouple with the swab With the dropper release cleaning solution onto the thermocouple mount Immerse the thermocouple and the entire sur face of the mount in cleaning solution Let stand at least 1 minute SECTION 4 PREVENTIVE MAINTENANCE 43 Cleaning the TC Head 4 Hold the TC head over the waste container 5 Quickly pull the TC head straight down and away from the droplet of liquid allowing liquid to fall into the waste container directly below 6 Immediately apply rinse water before evaporation can occur Use purified water with resistivity of 1 or higher for rinsing Water of lesser quality will contaminate the thermocouple CAUTION Do not contaminate the rinse wat
4. plunger NOTE Normally sample droplets will not cling to the outside of the tip If they do they can usually be removed simply by dragging the tip against the lip of the container as you remove it Occasionally a clinging droplet may have to be removed with a tissue but be very careful not to wick solu tion out of the tip 35 SECTION 3 OPERATING THE VAPRO OSMOMETER 3 2 Loading Samples 36 Touch Tip to Sample Disc Press Disc lat With the pipettor tip resting in the notch of the pipettor guide position the tip about 5 millimeters above the center of the sample disc Smoothly depress the micropipettor plunger to the stop The specimen may drop onto the sample disc Whether the sample droplet falls onto the disc or clings to the tip you must complete Step 6 CAUTION Never allow the micropipettor tip sample material or the wet disc to touch the outer surface of the sample holder If this occurs abort the measurement and wipe the sample holder clean before proceeding CAUTION Break any air bubbles on the sample disc before proceeding A bubble bursting inside the sample chamber will contaminate the thermocouple With the plunger still held against the stop lightly touch the micropipettor tip to the sample disc then lift it away The tip must briefly contact the sample disc to press it flat against the holder The paper disc should appear fully saturated with a slight liq uid menisc
5. 34 45 46 48 54 58 61 62 65 66 85 damage 55 59 62 63 65 66 70 85 deformed 62 63 65 66 68 restoring 69 70 junction bead 70 head access cover 12 13 15 46 52 Thermocouple cleaning 48 50 55 66 cleaning supplies 18 48 15 46 51 59 65 66 67 inspecting 66 oxidation 56 removing 45 46 47 66 reinstalling 51 67 screws 59 61 62 64 65 hygrometer 10 76 hygrometry 76 mount 10 65 70 sensor 65 temperature graph 78 79 Tissue Paper 82 Troubleshooting Flow Chart 58 59 U Unit of Measure 20 101 User s Manual 7 18 Vv Vapor Equilibration 31 Vapor Pressure determination 9 equilibration 10 method 9 Viscosity sample 9 81 Voltage 71 Voltage Selector 16 27 changing 27 Volumetric error 68 88 101
6. Aligns and steadies the pipette for precise application of the speci men onto the sample disc in the sample holder Sample Holder Standard sample holder for samples up to 10 microliters in volume Requires solute free paper discs provided for use Other sample holders are available for special applications see Appendix B and D Sample Slide Moves the sample holder from the loading position under the pipette guide to the sample chamber Power Indicator The green light indicates the instrument is on INSTRUMENT TOP TC Head Access Cover Provides access to thermocouple head for cleaning and mainte nance Press down on the right side of the cover to remove 13 Serial Data Port Signal Chime Model and Serial Sample Chamber Lever Numbers Shown in the Open Position Power Entry Module 14 SECTION 1 INTRODUCTION 1 5 Controls and Features INSTRUMENT RIGHT SIDE Sample Chamber Lever Opens and closes the sample chamber Closing the sample cham ber locks the sample holder within the chamber The chamber should remain closed except when loading or removing samples Closing the chamber initiates the measurement cycle or the Standby mode indicated by READY on the display screen if no sample is present INSTRUMENT INTERIOR The thermocouple TC head and thermocouple head connector are accessed by removing the chamber access cover from the top of the instrument INSTRUMENT REAR PANEL Signa
7. Clean Test reveals moderate levels of contamination will save time Cleaning is much more diffi cult if you wait until contamination interferes with normal calibration settings Cleaning the TC head requires removing it from the instrument Carefully follow directions to safeguard the thermocouple and ensure successful completion of the cleaning process 45 SECTION 4 PREVENTIVE MAINTENANCE 4 2 Removing the TC Head 1 Turn the power switch off Rotate the sample chamber lever to the open position Remove the TC head access cover from the top of the osmometer by pressing down on the right hand edge then lifting the raised edge up and away Remove the TC head connector by squeezing the locking tab and lifting 46 SECTION 4 PREVENTIVE MAINTENANCE 4 2 Removing the TC Head 5 Using the 9 64 inch hex driver completely loosen but do not remove from the TC head the attachment screws Grasp the top of the TC head with the attach ment screws and lift it straight up and out of the instrument Replace the access cover while the TC head is out of the instrument 7 Remove the attachment screws from the head CAUTION To avoid thermocouple damage invert the TC head with the thermocouple facing up before setting it down 47 SECTION 4 PREVENTIVE MAINTENANCE 4 3 Cleaning the TC Head 48 Materials needed to clean the TC head Wescor Cleaning Solution Cat SS 003
8. SECTION 3 OPERATING THE VAPRO OSMOMETER 3 1 Operation Overview 30 zmolalitu 2932 mmo1 kg zmolalitu nnorz ka Normal Mode Sample 3 Mean 5 0 1 21 High 291 Low 288 Average Mode The modes are described below Normal Mode For routine running of single samples Does not dis play any statistical data This mode is the default setting upon power up of the instrument Average Mode Will run single samples while maintaining statistical data on up to 32 samples These data include the number of samples run 1 to 32 mean standard deviation highest result and lowest result NOTE If a 33rd sample is run the result will displace the first sample a 34th sample will displace the second sample and so on The statistical evaluation will always be based upon the latest 32 samples if more than 32 samples are assayed Average Mode is useful when you need the best possible accuracy When the instrument is calibrated in Average Mode calibration is adjusted to the mean value of the assayed samples Calibration resets the operation mode to Normal Mode see Section 3 5 NOTE We recommend calibrating in Average Mode using 3 or 4 samples of each calibrating solution value To restart a new set of precision values bring up the Mode Menu the arrow should be pointing at Average Mode The next sample assayed will be sample 1 in the data group Or select the Mode Menu immediately af
9. Service MANUALS and INSTRUCTIONAL MATERIALS M2468 5520 Vapro Osmometer User s Manual M2469 5520 Vapro Osmometer Service Manual V 1003 Thermocouple Cleaning Video VHS Format specify NTSC PAL or SECAM 74 APPENDIX C Theory of Operation Osmolality is an expression of the total concentration of dissolved particles in a solution without regard for particle size density con figuration or electrical charge Indirect means for the measurement of osmolality are afforded by the fact that the addition of solute par ticles to a solvent changes the free energy of the solvent molecules This results in a modification of the cardinal properties of the sol vent i e vapor pressure freezing point and boiling point Compared with pure solvent the vapor pressure and freezing point of a solution are lowered while its boiling point is elevated provided that a single solvent is present in the solution Solutions containing more than one solvent generally behave in more complex ways In single solvent solutions the relative changes in solution proper ties are linearly related to the number of particles added to the sol vent although not necessarily linearly related to the weight of solute since solute molecules may dissociate into two or more ionic components Since these properties all change linearly in proportion to the concentration of solute particles they are known as colliga tive properties Osmotic pressure is also a co
10. a contaminant a gross contam ination or fiber on the thermocouple that is holding vapor If the displayed contamination level is greater than 10 you should perform the thermocouple cleaning procedures found in Section 4 SECTION 3 OPERATING THE VAPRO OSMOMETER 3 5 Calibrating For optimum operating accuracy the instrument must be correctly calibrated according to the instructions in this section Calibration accuracy depends upon three main factors e Standard solution accuracy e Thermocouple cleanliness e Loading technique repeatability NOTE Use Optimol glass encapsulated ampule standards for calibration Check calibration following the initial equilibration period after you first set up the instrument Thereafter we recommend that you check calibration before each session of use NOTE Calibration values are saved by the instrument when power is interrupted Instrument Response Characteristics Most clinical osmolality determinations range from 200 to 1000 mmol kg The inherent linearity of the vapor pressure method results in an extremely linear instrument response from 100 mmol kg to the upper limit of the osmometer s range 41 SECTION 3 OPERATING THE VAPRO OSMOMETER 3 5 Calibrating 42 zmolalitu 2932 nmol ks SELECT Osmolality 290 mmol kg 3Calibrate Clean Test Delete Result Meru Mode Initial or Routine Calibration 1 Run a 290 mmol kg standard I
11. and compensates for changing ambient temperatures that would otherwise result in calibration changes It also maintains a continuous balance in its thermocouple control circuitry to ensure convergence of the thermocouple to the pre cise dew point temperature during the measurement cycle These internal functions are necessary to maintain accurate performance That is why we recommend that the osmometer be left under power when not in use It is also why long measurement sessions should be interrupted periodically to allow the instru ment one full measurement cycle on a dry empty chamber NOTE Occasionally after a series of runs an osmolality reading appears on the screen after cycling on an empty cham ber This may be due to residual moisture on the sample holder If this occurs withdraw the sample slide and thor oughly clean the sample holder using lint free tissue Then return the slide to the measurement position and close the sample chamber 43 SECTION 3 OPERATING THE VAPRO OSMOMETER 3 7 Serial Data Output The 5520 serial port uses a DB9 connector on the instrument back panel This port is for asynchronous serial communication with a printer or computer It uses standard non return to zero NRZ format at RS 232 voltage levels The instrument senses when the RTS pin 7 is active When a sample is assayed while a device is con nected to the 5520 s RS 232 port the display status line will show EHTER
12. can be represented by a simple model i e water as solvent with nonvolatile solutes will have a linear uniform relationship among all of the colligative properties vapor pressure freezing point boiling point etc In addition most of these same solutions can be uniformly frozen with few artifacts arising from the freezing process Thus one can expect to obtain very similar results if not exact duplication between freezing point and vapor pressure measurements on the vast majority of clinical specimens Aside from this broad category of solutions there is a small but important class of solutions that may be encountered in clinical work where the colligative relationships do not necessarily hold These are solutions in which non physiological volatile solutes actually solvents are present In such cases the interactions among the various molecules cause the properties of such solutions to be more complex They generally do not follow linear relationships as in solutions having only a single solvent It must be remembered that osmometers for clinical applications whether based on freezing point or vapor pressure methodology determine the osmolality of solutions by indirect means When complex solutions are encoun tered the results obtained by either of these instruments may not faithfully represent the osmolality of the solution Each instrument will respond to the parameter it is designed to measure and the resultant indication
13. event you may as well make the attempt since a badly deformed thermocouple will not func tion Because of the delicate nature of the task you will need steady hands and a microscope preferably stereoscopic having magnification in the range of 30X to 60X 69 SECTION 5 SOLVING PROBLEMS 5 4 Deformed or Broken Thermocouple 1 Make a tool by cutting a thin sliver or wedge J from a sheet of ordinary paper 2 Work the pointed end of the paper sliver under the thermocouple wire 3 Use the paper sliver to lift and reshape the thermocouple The paper sliver is sufficiently flexible to avoid undue stress on the thermo couple wires Shape the thermocouple to a rounded arch that is perpendicular to the sur face of the TC mount as illustrated The junc tion bead should be at the high point of the arc 4 Thoroughly clean the thermocouple Section 4 before reinstalling the TC head Broken Thermocouple Usually a broken thermocouple is readily evident especially under a microscope On rare occasions the thermocouple may have an intermittent electrical connection that will cause highly erratic behavior in the osmometer A break at either of the thermocou ple connection points may require meticulous inspection to discover A broken thermocouple requires replacement of the TC head Contact your dealer or Wescor for assistance 70 APPENDIX A Instrument Specifications Sample Volume 10 pL nominal Larger sample
14. in depth information throughout this manual The suggestions listed here are intended to help you quickly solve routine problems For unusual problems which require more detailed information about the operation of the osmometer refer to the Vapro Service Manual If you have tried all these suggestions and still need help contact your dealer or Wescor for assistance Refer to Customer Service Section 1 2 57 SECTION 5 SOLVING PROBLEMS 5 1 Troubleshooting Large Shift inO Poor Linearity inO No Display Calibration Low Range Is PowerO Indicator Lit Is Temperature r Yes Stable No p Temperature toO Stabilize Yes Check if PowerO Switch is On Obtain Fresh O Standards Are CalibrationS StandardsO Fresh Yes Check Power Receptacle MESSAGEL Error Use OnlyO With 100 Run CleanO Test Using 1000 mmol kg Check Fuses ContaminationL level gt 10 Yes Clean Thermocouple Check DisplayO Connector RecalibrateO Instrument InstrumentO Repair Required Performed By Qualified Personnel Only 58 SECTION 5 SOLVING PROBLEMS 5 1 Troubleshooting MESSAGEO ERROR CheckO MESSAGEQO AbnormalOl Erratic Heading Calibration Error Display Thermocouple Run an Auto 0 Repeat usingO 1000 Check TCO Connector RestartO Verify Calibration 0 Standard
15. or immedi ately after running a prior sample but before opening the sample chamber After you select a mode all samples are processed in that mode until you select a different mode Functions are specific actions the osmometer can perform The Function Menu is not available until you have assayed a sample wexcar Chamber Oren Press SELECT to move the selection arrow on the 7 g 1 mmol kg display Press ENTER to activate the selected menu item If you continue to press SELECT the arrow will ahorn al Mose return to the top of the menu Auto Rereat Process Delay MODE MENU Mode Menu The Mode Menu appears upon opening the chamber while the instrument is in the standby mode the instrument has cycled on an empty chamber or Osmolality when you select Mode Menu from the Function 1 Menu when press SELECT while the Calibrate Clean Test When you activate the Mode Menu the arrow points Delete Result to the current mode When you close the chamber Mode Menu or press ENTER with the chamber open the instru ment executes the sample measurement in the selected mode You can change the mode at any time before the measurement cycle begins or on the last sample before the sample chamber is opened To activate the Mode Menu after a sample has been run either select Mode Menu from the Function Menu or open the chamber and press SELECT Function Menu 29
16. shift in calibration and replace if needed See Section 4 Run the Clean Test If the contamination level is greater than 10 clean the thermocouple If the contamination level is less than 10 recalibrate the instrument There is poor linearity Check the Temperature Drift Scale on the display to see in the low range below if temperature is stable If necessary allow the 200 mmol kg instrument to stabilize See Section 2 3 Verify that you are using fresh calibration standards See Section 4 Run the Clean Test Section 3 4 using the 100 standard If contamination is greater than 10 clean the thermocouple using the instructions in Section 4 If you run the Clean Test and the dis play shows ERROR Use only with 100 mmol kg standard this may indicate that ERROR you incorrectly used a 290 mmol kg or only with 1000 mmol kg standard for the test Run ise 100 ka the Clean Test again using the 100 mmol kg Standard standard If while using the100 mmol kg standard you see ERROR Use only with 100 mmol kg standard on the display check for loose TC head screws 61 SECTION 5 SOLVING PROBLEMS 5 1 Troubleshooting Problem Continued There is poor linearity in the low range below 200 mmol kg Scrambled or erratic reading on the display or poor repeatability The display shows 62 Solution If after taking the above steps the error message again appears after running the Clean Test che
17. the instrument into the outlet To change the voltage selector 1 Switch the power off and remove the power cord from the power entry module Use a screwdriver to open the fuse door from the switch left side Pull the voltage selector away from the mount ing slots Rotate the indicator until the correct voltage is facing directly outward then press it back into the slots W N Change the fuses to match the new voltage setting See Section 2 8 for fuse replacement instructions 6 Close the fuse access door and verify that the correct voltage now appears in the indicator window 115Vac 230Vac 27 SECTION 2 GETTING STARTED 2 8 Changing Fuses To access the main fuses 1 Turn power off and disconnect the power cord 2 Use a small screwdriver to open the fuse door For continued protection against fire hazard onlv use fuses of the correct type and rating Fuse Specifications 115 V Setting 1 8 ampere time delay type 1 4 x 1 1 4 2 required 230 or 240 V setting 1 16 ampere time delay type 1 4 x 1 1 4 2 required Refer to Specifications Appendix A 28 SECTION 3 OPERATING THE VAPRO OSMOMETER 3 1 Operation Overview Menu Selections Two main menus Mode and Function are used to select modes and functions of the osmometer Modes control how the osmometer processes sam ples and displays results Use the Mode Menu to select the mode before loading a sample
18. to Send To send data to the external device press ENTER The display will show Osmolality See Appendix F for more information 44 SECTION 4 PREVENTIVE MAINTENANCE 4 1 Preventive Maintenance Overview Cleaning the thermocouple TC head is the only routine mainte nance required by the Vapro osmometer This section will guide you through the necessary steps of removing cleaning and reinstalling the TC head Also included are methods for identifying and resolv ing more difficult thermocouple contamination situations During normal use dust or lint particles gradually accumulate in the sample chamber Reasonable care in loading and removing sample material from the sample holder usually makes it possible to run at least 100 assays before cleaning becomes necessary Gross contamination is usually a result of incorrect sample loading or incompletely removing sample material from the sample holder following an assay When correctly operated sample material will never contact internal chamber parts See Section 3 2 Under heavy use run the Clean Test when the osmometer has assayed 100 samples Record the results of this test When the Clean Test shows moderate contamination Clean Test reading of around 10 try rinsing the TC mount as explained in Section 4 3 If simple rinsing fails to correct the problem you will need to perform the full cleaning procedure as outlined in Section 4 3 Cleaning the TC mount as soon as the
19. 1 APPENDIX F Serial Data 93 APPENDIX G Setup Men 95 INDEX alba a ra puq acum 97 SECTION 1 INTRODUCTION 1 1 User s Manual Overview Thank you for purchasing the Vapro vapor pressure osmometer You will find it to be a valuable investment and an important partner in the laboratory The Vapro User s Manual is your key to efficiently operating this instrument We recommend that you become thoroughly familiar with the operation procedures and troubleshooting techniques described in this manual Information is presented in a step by step format to demonstrate the operation and care of the instrument from a first time user s point of view Once you become familiar with the operation of the Vapro osmometer the manual will help you maintain the instrument in a high state of precision and reliability SPECIFICATION OF SAFE USE Using this instrument in a manner not specified by Wescor may impair the safety protection designed into the equipment and may lead to injury SAFE USE ENVIRONMENT This equipment is designed to be safely operated at 5 to 35 C max imum relative humidity 8096 FUSE All fuses in this equipment are time lag Type T EXPLANATION OF SYMBOLS FOUND ON EQUIPMENT 7 Alternating Current AC Power On O Power off JN International Attention Symbol Calls attention to important informat
20. Added kg Osmolality Osmolality Osmolality mmol kg pL mg mmol mmol kg mmol kg mmol kg 289 2500 1953 42 331 340 287 289 5000 3905 85 374 392 285 289 10000 7810 170 459 501 282 289 25000 19525 424 713 798 277 289 50000 39050 849 1138 1400 250 out of cal 1 Instruments gave identical results on serum alone 2 Assuming 100 ethanol with a relative gravity of 0 78 90 APPENDIX E Osmolality Standards STANDARD INTERNATIONAL SI UNITS OF OSMOLALITY Osmolality by definition is an expression of the total number of solute particles dissolved in one kilogram of solvent without regard for particle size density configuration or electrical charge Traditionally osmolality has been expressed as milliosmols per kilo gram with various abbreviations such as mOs kg mOsm kg and mOsmol kg The letters Os signify that osmolality is defined as the concentration expressed on a molal basis of the osmotically active particles in true solution Thus one mole 1000 mmol of sodium chloride dissolved in a kilogram of water has an ideal osmolality of 2000 mOsm kg since a molecule of sodium chloride dissociates in solution to produce two ions that is two osmotically active particles In fact a molal solution of sodium chloride has an osmolality value slightly less than the ideal because the residual mutual attraction of the hydrated ions reduces their mutual independence due to the osmotic coefficient Since this coefficie
21. Clean Test using the instruc tions in Section 3 4 39 SECTION 3 OPERATING THE VAPRO OSMOMETER 3 4 Running the Clean Test 40 zmolalitu 100 Calibrate Clear Test Delete Result Mode Menu SELECT d nnolzks Contamination Z The Clean Test is a diagnostic feature that compares two consecutive sample assays and uses the differ ence to determine the contamination level of the thermocouple When To Run the Clean Test We recommend running the Clean Test before each session of osmometer use after calibration or any time you notice a significant 10 mmol kg or more shift in the 100 mmol kg calibration Check thermo couple cleanliness before assaying samples that require good linearity and accuracy in the low range After cleaning the thermocouple use the Clean Test to verify the effectiveness of the cleaning Instructions 1 Run a 100 mmol kg standard sample in Normal Mode Observe the reading Press CALIBRATE 2 Before opening the sample chamber press SELECT to reveal the Function Menu Press SELECT again to point the selection arrow at CLEAN TEST 3 Press ENTER The instrument performs a sec ond assay of the loaded sample and displays the difference between the first and second assay in approximately 2 to 3 minutes NOTE If the thermocouple fails to dry within 4 minutes the instrument will report Check Thermocouple Head This indicates the presence of
22. VAPRO VAPOR PRESSURE OSMOMETER MODEL 5520 USER S MANUAL M2468 4 1995 1998 2000 2002 Wescor Inc All rights reserved Printed in the United States of America Wescor Vapro Optimol Osmocoll and Blow Clean are trademarks of Wescor Inc Other trade names used in this manual may be trademarks of their respective owners used here for information only The information in this manual may change without prior notice TABLE CONTENTS SECTION INTRODUCTION 1 1 User s Manual Overview 7 1 2 Customer 8 1 3 Vapro System 9 1 4 How the Vapro Works 10 1 5 Controls and 12 SECTION GETTING STARTED 2 1 Instrument Setup 17 2 2 Accessories 18 2 3 Setting Up the 19 2 4 Micropipettor Information 22 2 5 Using Optimol Osmolality Standards 24 2 6 Using Osmocoll Serum Control 26 2 7 Changing Voltage 27 2 8 Changing FUSES 28 SECTION OPERATING THE VAPRO OSMOMETER 3 1 Operation Overview 29 3 2 Loa
23. ample disc or does not spread out over the whole disc naturally it may be preferable to eliminate the sample disc and use the pipettor tip to apply the material as uniformly as possible over the central depres sion of the sample holder In other situations materials can be sampled successfully by immersing the paper sample disc which is held in the forceps into the specimen to be tested then carefully transferring the wet disc to the central depression of the sample holder Caution must be exer cised when using this disc immersion technique to avoid any con tact of the wet sample disc with the outer portion of the sample holder since this would result in solute material being transferred to the thermocouple mount and would rapidly contaminate the sample chamber In any event when working with unusual specimens make certain the sample occupies the full diameter of the central depression in the sample holder as it would if saturated into a paper sample disc The thickness of the specimen should be as small as possible 88 APPENDIX D Special Application Notes OSMOMETRY WITH MULTI SOLVENT SOLUTIONS Biological solutions in general are aqueous in nature Most speci mens submitted to the clinical laboratory for testing both pathologic and normal will exhibit characteristic properties that are essentially attributable to the cardinal properties of water as modified by the dissolved solute particles Such solutions which
24. ceive Data output 3 TXD Transmit Data input oe eeo 4 N C No Connection 5 GND Signal Ground passive 6 7 8 9 6 DSR Data Set Ready output 7 RTS Request to Send input 8 CTS Clear to Send output 9 N C No Connection DSR is tied true whenever the instrument power is on DCD and CTS are internally tied together The serial port is configured as Data Communications Equipment DCE This enables the osmometer to be connected directly to most computers and printers which are usually configured as Data Terminal Equipment DTE Use a STANDARD PC AT type 9 pin to 25 pin serial cable Do not use a null modem cable unless your device is configured as DCE Data output is in ASCII characters Upon power up the osmometer will output the characters READY at the serial port At the comple tion of a sample assay the instrument looks for RTS to be true If this line is high ENTER to send is displayed on the top line of the display Press ENTER at this time to output the data on the serial port The data format is as follows 20 hex space Reading mmol kg OA hex line feed OD hex carriage return 94 APPENDIX G Setup Menu The Setup Menu allows you to select available lan guages English French or German and available measurement units mmol kg or kilopascals at 25 C 2 5 x mmol kg It also allows you go run a Self Test on the instrument to check basic input and out put functions Language and Units of Measurm
25. ck the TC mount for gross visible contamination A grossly contaminated TC mount requires extensive cleaning and may require replacement See Sections 5 2 5 3 and 5 4 If these procedures fail to resolve the problem contact your dealer or Wescor for assistance Section 1 2 Run a 1000 mmol kg standard in Auto Repeat Mode then check the standard deviation shown on the display If less than 2 0 assess your sample loading technique for possible loading errors See Section 3 2 If standard deviation is greater than 2 0 check for loose TC head screws See Section 5 2 If this is not the problem check the TC mount for gross contamination If these steps fail to resolve the problem contact your dealer or Wescor for assistance Check the TC connector for incomplete contact Check for loose TC head screws Remove the TC head and inspect the TC mount under a microscope for bent damaged or broken thermocouple If thermocouple is undamaged check for gross or visible cont amination If contamination is evident clean the thermocou ple according to instructions in Section 5 2 If these mea sures fail to work contact your dealer or Wescor for assis tance Section 1 2 Problem Calibration deteriorates after cleaning the TC mount Abnormal display or sample reading on an empty chamber or one of following Error messages ERROR IT ERROR CLE ERROR SECTION 5 SOLVING PROBLEMS 5 1 Troubleshooting Solut
26. d solution from ampules to other containers e Always follow the instructions in Section 3 5 to calibrate your Vapro osmometer and always verify calibration prior to running any unknowns See Appendix E for more information 25 SECTION 2 GETTING STARTED 2 6 Using Osmocoll II Serum Control Osmocoll II is processed stabilized bovine serum control which is useful in a quality assurance program for the Vapro osmometer For optimum results always adhere to the following guidelines Upon arrival in your laboratory refrigerate Osmocoll Il Under refrigeration the serum will remain stable until the labeled expiration date Once opened the product has a maximum stable life of 5 days if kept refrigerated and tightly capped Instructions CAUTION Never calibrate the Vapro osmometer using Osmocoll Il control solution 1 Run a sample of Osmocoll II control 2 If the measured osmolality falls outside of the range listed on the package labeling each Osmocoll lot is assayed for osmo lality you should suspect the calibration of the instrument Recalibrate the instrument using freshly opened Optimol ampule standards See Section 3 5 for instructions 26 SECTION 2 GETTING STARTED 2 7 Changing Voltage Selector The voltage selector is set at the factory If the volt age shown does not match your power outlet see Appendix A for nominal voltage ranges you must change the voltage selector before plugging
27. ding Samples 34 3 3 Cleaning the Sample 39 3 4 Running the Clean 40 3 5 Calibrating eie ease aa RR 41 3 6 Standby or Waiting Periods 43 3 7 Serial Data 44 TABLE CONTENTS SECTION 4 PREVENTIVE MAINTENANCE 4 1 Preventive Maintenance Overview 45 4 2 Removing the TC 46 4 3 Cleaning the TC 48 4 4 Reinstalling the TC Head 51 4 5 Equilibration After Cleaning 53 4 6 Severe or Stubborn 54 SECTION 5 1 Troubleshooting RR x 57 5 2 Common Head 65 5 3 External Factors Affecting Precision 68 5 4 Deformed or Broken Thermocouple 69 APPENDIX A Instrument Specifications 71 APPENDIX B Accessories Supplies and Replacement Parts 73 APPENDIX Theory of 75 APPENDIX D Special Application 81 5 APPENDIX E Osmolality Standards 9
28. e each osmometer use session This will allow you to monitor the condition of the thermo couple sensor and the rate at which contamination builds up in the sample chamber See Section 3 4 for instructions SECTION 3 OPERATING THE VAPRO OSMOMETER 3 1 Operation Overview Delete Result Deletes the last result from the data group You can delete multiple results using this function This function can only be used while operating in Average Mode Returning to Mode Menu Press ENTER while the arrow points at MODE MENU to exit the Function Menu and return to the Mode Menu NOTE Calibration is a critical element of instrument accuracy While it is not nec essary to calibrate the osmometer while familiarizing yourself with it you should check calibration before you assay sample material see instruc tions in Section 3 5 33 SECTION 3 OPERATING THE VAPRO OSMOMETER 3 2 Loading Samples When first using the Vapro system practice the loading procedure using the micropipettor and the 290 mmol kg standard Record the value dis played at the end of the cycle when the In Process display goes out and the chime sounds Practice this procedure until you can obtain sequential results with a spread of less than 6 mmol kg Consistent tim ing during loading is important for optimum repeatability This will come naturally after a few samples NOTE While you practice do not be concerned if the instrument readings do not agree with t
29. e of the Wescor micropipettor 22 SECTION 2 GETTING STARTED 2 4 Micropipettor Information Sample Volume Considerations The Vapro osmometer does not demand a high degree of volumet ric accuracy at the 10 yL sample level Sample volume variations of 10 percent will not noticeably affect the final result Gross volu metric errors such as might arise from incorrect pipetting technique or poorly maintained micropipettors or micropipettors not approved by Wescor can cause significant measurement errors 23 SECTION 2 STARTED 2 5 Using Optimol Osmolality Standards Wescor s Optimol ampule osmolality standards are accurate enough to satisfy the most stringent quality assurance requirements Calibration integrity is assured because ampules provide fresh solution for each use Having the accuracy of reference stan dards Optimol standards are ideal for routine osmometer calibration Optimol standards are manu factured under strict quality control and have a minimum storage life of 36 months Refer to Appendices B and E for more information NOTE Ampule standards are intended for one time use for no more than a few hours When you have finished calibra tion discard any remaining solution Instructions Each ampule contains 0 4 mL of solution This vol ume is sufficient to prevent measurable evaporative concentration for a few hours after the ampule is opened 1 Flip the stem of the ampule w
30. e per formed without the necessity for a change in the physical state of the specimen It is thus a passive technique of measurement that is free from measurement artifacts that often occur when the speci men to be tested must be altered physically This fundamental dif ference in methodology gives rise to the many advantages of the vapor pressure osmometer over the older method In the Vapro vapor pressure osmometer a 10 microliter sample of the solution to be tested is pipetted onto a small solute free paper disc which is then inserted into a sample chamber and sealed A thermocouple hygrometer is incorporated integrally within the cham ber This sensitive temperature sensor operates on the basis of a unique thermal energy balancing principle to measure the dew point temperature depression within the chamber This parameter in itself a colligative property of the solution is an explicit function of solu tion vapor pressure PROGRAM STEP 1 EQUILIBRATION AND ZERO SET The sample is introduced into the chamber and the chamber is closed Simultaneously Process a countdown by seconds is displayed This remains until the end of sequence at Program Step 4 At this point there will generally be some difference between the temperature of the specimen and the temperature of the sample chamber Temperature equilibrium occurs within a few seconds The vapor pressure may also reach equilibrium during this interval The microv
31. e the contami nant simply by applying a droplet of purified water to the thermocouple and allowing it to stand for 30 to 60 minutes Causes of Unusual Contamination While there are many potential causes of unusual contamination the following are the most common A severely contaminated thermocouple with visi ble accumulations of organic matter or salt deposits is evidence of incorrect or careless loading procedures Careless loading of greasy waxy specimens Q Failure to clean fingerprints or other deposits from the sample holder Oily residue from compressed air lines when an air jet is used to blow water droplets from the thermocouple after cleaning Improper use of Blow Clean Liquid discharged from the can onto the thermocouple mount leaves an oily deposit that is difficult to remove 54 SECTION 4 PREVENTIVE MAINTENANCE 4 6 Severe or Stubborn Contamination Removing Difficult Contamination Many contaminants can be detected and removed under microscopic examination If cleaning fails to produce an acceptable clean test examine the ther mocouple head under a microscope at 30X to 60X power Gross contamination can usually be removed by repeated cleanings although mechanical scrubbing as described below may expedite the process NOTE Concentrated ammonium hydroxide from local stores can be used to remove stubborn contaminants but it may not be effective on oily greasy or waxy ma
32. ea To Start Cucle surement can be repeated without opening the chamber and to avoid vapor loss See Appendix D for more information Process Delay Mode 31 SECTION 3 OPERATING THE VAPRO OSMOMETER 3 1 Operation Overview 32 zmolalitu 100 Calibrate Clear Test Delete Result Mode Menu Function Menu jj nnolz ks Contamination Z FUNCTION MENU To display this menu press SELECT after a sample has been assayed and before opening the sample chamber The osmometer performs the function indi cated by the arrow when you press ENTER Calibrate Function Use this function to calibrate the instrument using the 290 1000 and 100 mmol kg calibration stan dard Always begin with the 290 set point then fol low with the 1000 and 100 mmol kg See Section 3 5 for details Clean Test The Clean Test consists of two consecutive sample assays on a 100 mmol kg standard solution The dif ference between the first and second assay indi cates the degree of contamination in the sample chamber Run this test if you notice significant changes in the 100 mmol kg calibration level Always use the Clean Test to check thermocouple cleanliness before assaying samples which require good linearity and accuracy in the low range After thermocouple cleaning use the Clean Test to verify the effectiveness of the cleaning We recommend that you perform this test on a rou tine basis befor
33. en each screw progressively with the 9 64 inch hex driver until all four are firmly tightened 4 Reinstall the head connector 51 SECTION 4 PREVENTIVE MAINTENANCE 4 4 Reinstalling the TC Head 5 Replace the access cover 6 Close the sample chamber 7 Turn on the power Allow the instrument to complete the initial ization sequence and reach equilibrium see Section 4 5 8 Perform the Clean Test If the test indicates a clean thermo couple head you should calibrate the osmometer before pro ceeding to run samples If the Clean Test reveals contamination refer to Section 4 6 and if necessary Section 5 1 52 SECTION 4 PREVENTIVE MAINTENANCE 45 Equilibration After Cleaning Cleaning the thermocouple mount changes the thermal equilibrium of the instrument and causes a temporary shift in calibration after the TC head is reinstalled After reinstalling the thermocouple head allow the instrument to regain thermal equilibrium The Temperature Drift indicator will be near center when the osmometer temperature is stable See Section 2 3 53 SECTION 4 PREVENTIVE MAINTENANCE 4 6 Severe or Stubborn Contamination If the Clean Test indicates residual contamination in spite of a clean appearance 1 Repeat the cleaning procedure and run a sec ond Clean Test If there is significant improve ment contamination can likely be removed by repeated cleanings 2 You can often successfully remov
34. ent are initially des ignated at the factory and stored in non volitile mem ory They become default settings on power up of the osmometer and are displayed briefly at that time To change these settings 1 Turn off power Wait aproximetely 10 seconds 2 While pressing both the SELECT and ENTER keys turn the on power Wait several seconds while the display shows the Wescor logo default selections and finally the Setup Menu Select desired language or unit of measure 3 ment using the SELECT button to move the point er to your choice Press ENTER to add selection to memory 4 Once you have selected your preferences you can exit the setup menu The instrument defaults to these settings until they are changed 95 Accuracy of standards 24 25 of reported osmolality 25 Ambient Temperature 10 43 60 82 Ammonium Hydroxide 48 55 56 Ampule organizer 18 24 standards see Optimol ASCII Characters 94 Average Mode 30 42 Auto Repeat Mode 31 59 62 68 B Blow Clean 18 50 74 C Calibrate Function 32 Calibration accuracy 25 51 63 adjusted to mean value 30 effects of temperature changes on 21 error 59 64 for maximum accuracy 42 for very large samples 86 for very small samples 84 in Average Mode 30 acceptable limits 42 procedure 41 routine 42 52 shift 38 53 58 60 61 62 standards 24 42 58 61 64 68 verifying 25 32 33 59 71 Carry over Error 88 Chime signal 14 37 77 warning 20 38 Cla
35. er by touching the tip of the water dropper or the water drop to the water stand ing on the mount Dilute any remaining droplets of cleaning solu tion with pure water 8 Repeat Steps 4 5 and 6 49 SECTION 4 PREVENTIVE MAINTENANCE 4 3 Cleaning the TC Head Repeat this procedure at least ten times using enough water to cover the central depression and thermocouple ESS CAUTION Shaking or tipping the can of Blow Clean will severely contaminate the thermocouple The can must remain flat on the bench 10 Place the Blow Clean upright and level on the bench Clear the nozzle with a short burst of gas Hold the TC mount about 2 inches from the nozzle then aim the nozzle directly at the thermocouple and release a very short burst no more than 1 second to blow away any remaining droplets 1 1 Inspect the TC mount for any residual conta mination If foreign material cannot be removed using this procedure refer to Section 4 6 NOTE Some contamination is invisible even under the micro scope Inspection can reveal many types of contamina tion but cannot replace the Clean Test 50 SECTION 4 PREVENTIVE MAINTENANCE 44 Reinstalling the TC Head Verify that the sample chamber lever is in the open position 2 CAUTION The instrument will not hold calibration if the chamber screws are loose Start each screw into the threads then tight
36. f the osmometer reads within 3 mmol kg of the standard 287 to 293 it is within accept able calibration limits In that case skip to Step 4 If calibration is needed proceed to Step 2 With the chamber still closed press SELECT to reveal the Function Menu The selector arrow should be pointing at Calibrate Press ENTER The instrument calibrates to the standard 4 Repeat this sequence using the 1000 mmol kg and 100 mmol kg standards to establish base line calibration for these standards If the read ing is not within 3 of the standard value per form steps 2 and 3 Calibration Method for Maximum Calibration Accuracy When you need maximum accuracy run the following calibration sequence 1 Select Average from the Mode Menu Run three consecutive assays using 290 mmol kg standard 3 Select CALIBRATE and press ENTER The instrument calibrates on the average of the three samples This method can also be used for 100 and 1000 mmol kg standards Chamber Emrtu READY gt E B Tenrerature Drift SECTION 3 OPERATING THE VAPRO OSMOMETER 3 6 Standby or Waiting Periods When the instrument is not in use leave the cleaned sample holder empty and locked in the measure ment position If the chamber is left open for longer than 2 minutes a warning chime sounds When in the standby mode the Vapro osmometer is not idle It continuously monitors its internal operat ing temperature
37. he specified concentration of the solution When you feel comfort able with the procedure and are able to obtain repeatable results calibrate the instrument using the instructions in Section 3 5 then run the Clean Test Section 3 4 Sample Volume The optimum sample volume 10 microliters should fully saturate one of the SS 033 sample discs The osmometer accommodates varia tions in sample volume as great as 10 percent 9 microliters to 11 microliters without noticeable variation in indicated osmolality CAUTION Samples greater than 11 microliters can contaminate the thermocouple 34 SECTION 3 OPERATING THE VAPRO OSMOMETER 3 2 Loading Samples Sample Loading Procedure 1 Rotate the sample chamber lever upward and pull the sample slide out from the instrument until it comes to a stop bringing the sample holder direct ly under the pipettor guide 2 Use the forceps supplied with the instrument to place a single sample disc in the central depres sion of the sample holder Make sure you have picked up only a single disc If necessary use the forceps and a teasing needle to separate discs If two discs stick together the reading will be slightly elevated Reject imperfect discs or any that do not lie flat 3 With a clean tip installed aspirate a sample into the micropipettor by depressing the plunger to the Place Sample Disc in Sample Holder stop immersing the tip and gently releasing the
38. he time required to achieve temperature stability depends on the initial instrument temperature typically 10 to 30 minutes but may be longer if inital temperature varies more than 5 degrees from room temperature NOTE Under normal circumstances leave power on to keep the instrument in a ready state and to maintain stability See Section 3 6 21 SECTION 2 STARTED 2 4 Micropipettor Information The micropipettor furnished with the Vapro osmometer uses a two step aspirate expel mechanism that dispenses 10 microliters of liq uid for osmolality assay This no maintenance micropipettor works with a wide range of biological solutions and laboratory reagents Disposable plastic tips eliminate carry over error from sample to sample Use the provided micropipettor to assure uniform results among different operators We do not recommend three step pipetting aspirate expel blowout for loading the osmometer The blowout step tends to create bub bles in the specimen that can lead to thermocouple contamination Positive Displacement Pipettors A positive displacement pipetting device or alternative loading meth ods may be more suitable for extremely viscous fluids or complex specimens CAUTION Do not use positive displacement pipetting devices for routine operation Refer to Appendix D for additional information regarding special applica tions The sample loading procedure in this manual presumes the us
39. hen the initialization cycle is complete the display screen will appear as shown on the left NOTE Even though the screen at this point indicates the instru ment is ready calibration will not be stable until the instrument reaches thermal equilibration see below Temperature Drift Scale Osmolality determination involves the measurement of extremely small temperature differentials The osmometer is thus sensitive to ambient temperature changes which induce internal temperature changes 20 SECTION 2 GETTING STARTED 2 3 Setting Up the Osmometer While the instrument compensates for small chang es that occur over time moving the instrument to a different area or exposing it to too much air circula tion will shift the osmometer s reading and calibra Chamber Empet tion points The Temperature Drift scale allows you R E D Y s to determine when internal temperature has stabi lized m mmu Tenrerature Drift The Temperature Drift scale appears on the screen whenever the instrument is in the standby mode and it has completed two cycles The instrument is considered stable and ready to operate unless the indicator is against the or marks on the scale indicating a changing internal temperature that can affect instrument calibration See Note below NOTE It is normal for the osmometer to undergo a significant temperature drift during the first few minutes of equilibra tion T
40. holder Push the sample hold er into the chamber and close the chamber Solid or some viscous samples require extended periods to reach equilibration inside the chamber On such samples you may want to make repeated measurements without opening the chamber to determine the time required to achieve equilibrium Osmolality val ues will trend downward until they stabilize If you know the required time simply defer the measurement for that period 86 APPENDIX D Special Application Notes 5 Press ENTER to make a measurement Osmolality is dis played when the measurement is complete 6 For repeat measurements leave the chamber closed and press ENTER Readings should be lower with each successive assay until equilibrium is reached 87 APPENDIX D Special Application Notes SAMPLING VISCOUS AND OR NONHOMOGENEOUS SPECIMENS The broad range of specimen materials amenable to testing in the vapor pressure osmometer may require you to adapt your sampling technique to suit the physical characteristics of unusual samples Using the micropipettor will assure the application of uniform vol umes of both test specimen and calibrating solutions but if the vis cosity of the sample is extremely high a positive displacement micropipettor may be preferable for sampling These devices are not recommended for routine use however due to their propensity toward carry over error If the sample material does not readily saturate the paper s
41. ion Check for deformed or broken thermocouple Reset instrument by turning the power off for at least 15 seconds then turn power back on Be sure the sample holder is thoroughly clean and dry before closing the sample chamber see Section 3 6 If this fails to resolve the problem contact your dealer or Wescor for assistance 63 SECTION 5 SOLVING PROBLEMS 5 1 Troubleshooting 64 Problem The following error message appears on the screen Calibration ERR E Value not within range Solution Be sure that you are using the correct calibration standard Check the TC head connector for faulty connection Check the thermocouple for gross contamination Check for loose TC head screws If these steps fail to solve the problem contact your dealer or Wescor for assistance SECTION 5 SOLVING PROBLEMS 5 2 Common TC Head Problems Many years of field experience have shown that the majority of problems encountered with the osmometer are with the thermocou ple sensor It is suspended from the thermocouple mount which forms the upper half of the sample chamber The thermocouple mount is part of the thermocouple head assembly referred to simply as the TC head Common thermocouple problems affect instrument performance in distinctive ways providing significant clues that will be evident in the behavior of the instrument These are summarized below in order of most likely occurrence COMMON TC HEAD PROBLEMS
42. ion and instructions in the instruction manual SECTION 1 INTRODUCTION 1 2 Customer Service Wescor is ready to help resolve any difficulty with the operation or per formance of your Vapro osmometer If you cannot solve a problem using the procedures in this manual please contact us Customers within the United States are encouraged to contact us by telephone Outside the U S many of our authorized dealers offer complete customer service and support Contact Wescor by mail telephone or fax at the address and numbers listed below WESCOR INC 459 South Main Street Logan Utah 84321 USA TELEPHONE 435 752 6011 Extension 0 Operator 171 Orders 172 Service TOLL FREE U S and Canada 800 453 2725 Extension 0 Operator 171 Orders 172 Service FAX 435 752 4127 E MAIL service wescor com WEB SITE WWW Wescor com SECTION 1 INTRODUCTION 1 3 Vapro System Description The Vapro osmometer is an advanced electronic adaptation of the hygrometric method of vapor pressure determination The sensitive thermocouple and sophisticated electronics provide the means to measure the dew point temperature depression of a specimen with resolution to 0 00031 C Vapor pressure and freezing point are among the colligative proper ties of a solution Compared with pure solvent these properties are altered in proportion to the number of solute particles dissolved in each kilogram of solvent water in the case of biologica
43. is can cause unwanted calibration shifts See Section 3 6 9 Remove the specimen from the sample chamber immediately after a measurement using the instructions in Section 3 3 If the sample is left in the chamber for longer than 4 minutes a warn ing chime will sound CAUTION You can severely contaminate the chamber or the thermocouple in a single loading if you improperly load the sample or if you fail to thoroughly clean the sample holder Severe contamination can make it impossible to calibrate the osmometer 38 SECTION 3 OPERATING THE VAPRO OSMOMETER 3 8 Cleaning the Sample Holder To clean the sample holder and prepare for another sample Smoothly rotate the chamber lever to the open position then withdraw the sample slide Using a lint free tissue not facial tissue or a cotton swab carefully remove the wet disc and any traces of residual liquid from the sample holder CAUTION Remove Sample and Clean Sample Holder Never use metal forceps to remove wet discs this can damage the surface of the sample holder 3 Leave no visible residue on the holder surface If needed use a tissue or swab moistened with deionized water Always clean the sample hold er with a fresh tissue or swab to avoid contami nation Avoid touching the sample holder with bare fingers The sample holder should appear bright shiny and perfectly dry before loading the next specimen NOTE Regularly perform the
44. ith the required equilibration time for a partic ular type of sample you can simply leave the chamber closed for the required time and then press ENTER to begin the osmolality measurement The standard sample holder has a diameter of 7 mm and a depth of 1 25 mm Two optional sample holders are available from Wescor for measuring samples which are too large for the standard sample holder e AC 064 sample holder is 7 mm dia x 2 5 mm deep e AC 065 sample holder is 9 5 mm dia x 4 5 mm deep 85 APPENDIX D Special Application Notes Instructions For best precision use the smallest holder that can accommo date the sample volume without danger of contaminating the thermocouple CAUTION Never load any sample that extends above the lip of the sample holder Solid sample material extending above the lip of the sample holder can severely contaminate or even break the thermocouple 2 Calibrate the instrument Use the same size sample holder as will be used for the assayed sample Match the volume and shape of the subject sample and the calibration solution as closely as possible Several filter paper discs saturated with standard solution should be used for calibration to dampen the motion of the solution and to approximate the size and shape of the sample material 3 Select Process Delay Mode This allows you to delay the mea surement cycle after closing the chamber until you press ENTER 4 Place the sample in the sample
45. ith your finger or tap the ampule lightly against a hard surface to dislodge any solution held by capillary action in the stem of the ampule 2 Place the ampule in the breaker position of the Ampule Organizer Hold the organizer firmly down against the work surface 3 Slide the provided flexible protection sleeve over the stem of the ampule 4 Grasp the sleeved stem firmly and snap the neck of the ampule 24 SECTION 2 STARTED 2 5 Using Optimol Osmolality Standards Sample directly from the ampule using a fresh micropipettor tip each time to avoid contamination of the solution Discard any solution that remains after finishing your calibration procedures Optimol standards are packaged in 60 ampule cartons designed for convenient shipment and storage See Appendix B for ordering information Assuring Accurate Measurements The accuracy of reported osmolality is directly linked to the accuracy of the calibrating standard solutions While these solutions have exact specified osmolality at the time they are opened osmolality inevitably increases as water evaporates Always adhere to the following guidelines when using Optimol ampule standards e Since the specified value of osmolality is certain only at the time the ampule is opened do not rely on any opened ampule if you are uncertain of how long its contents have been exposed to evaporation e Sample directly from the ampule do not transfer standar
46. ity assay by older macro methods especially since other analytical parameters are very often simultane ously requested on such specimens An equally important advantage is that the vapor pressure osmometer does not physically change the sample Where biological specimens or medications are multiphasic or highly viscous vapor pressure osmome try becomes the only reliable method of measurement For example feces sputum and gastrointestinal aspirate specimens usually contain variable amounts of mucous material that interferes with or prevents freezing point depression measurements but does not affect vapor pres sure osmometry Neither does the presence of finely suspended insolu ble material a feature of radio opaque media which are often examined to detect grossly high osmolality values likely to produce rapid dehydra tion when given to small infants In general research the potential applications are too numerous 10 list However the vapor pressure osmometer is of value to a wide range of biologists and microbiologists concerned with fluid and electrolyte bal ance in all forms of life especially where specimens are necessarily very limited in size and may exhibit unusual viscosity The instrument is capable of vapor pressure determinations expressed as osmolality even on complex specimens such as tis sue sections Such specimens should be cut to approximately the diameter and thickness of the paper sample disc if possible F
47. l Application Notes SPECIAL LOW VOLUME PROCEDURE Preparing Paper Discs 1 Use a Mieth or equivalent 1 8 inch diameter punch to create a supply of paper discs Punch only one thickness of paper stock at a time to prevent paper discs from sticking together That along with static electricity will make it difficult to pick up a sin gle disc with the tweezers 2 After punching remove paper discs from the retainer of the punch Store discs in a clean static free container As stated before very low volume tests require careful and consis tent technique to achieve reliable results The following are impor tant for you to consider when running samples with very low vol umes e Use only single sample discs Because of their small size you must be careful not to load more than one e Discs must be punched cleanly no ragged edges e The sample holder must be kept very clean e Do not exceed 4 uL of sample in the special sample holder Using too much sample fluid can severely contaminate the thermocouple e The paper disc must be completely saturated by sample fluid If not fully saturated the disc may appear patchy In this condition data will be inconsistent and repeatability will be poor NOTE Very small samples of less than 2 microliters can be successfully mea sured using lighter paper for the discs You should experiment with various papers Be cautious that some papers contain electrolytes that make them unsuitable S
48. l Chime Sounds a short chime at the conclusion of each measurement cycle and a long chime when certain fault conditions exist Turn the shut ter wheel to adjust volume Serial Data Port For asynchronous serial communication with a printer or computer The serial port uses a DB9 connector at RS 232 voltage levels See Appendix F for more information 15 SECTION 1 INTRODUCTION 1 5 Controls and Features 16 Power Entry Module Fuse Door Power Switch 1 on 0 off Voltage Selector INSTRUMENT REAR PANEL Continued POWER ENTRY MODULE Accepts standard IEC 320 type power cord Fuse Door Provides access for fuse replacement See Section 2 8 for instructions Power Switch Switches power on 1 or off 0 Voltage Selector This selector is set at the factory If necessary you can set the selector to match your local power source see Section 2 7 Fuses must match the voltage selection To change fuses see Section 2 8 and Appendix A Using this equipment in a manner not specified by Wescor may impair the provided safety protection SECTION 2 STARTED 2 1 Instrument Setup Sequence We recommend that you follow this sequence if you are using this instrument for the first time Details about these operations are found in the following sections i Inspect accessories and supplies 2 Place the instrument on a suitable work surface in an area free from drafts 3 Plug in the powe
49. l solutions Thus measuring either property is an indirect means of determining solution concentration or osmolality The chief advantage of the vapor pressure method is that it does not require alteration of the physical state of the specimen Concomitant benefits include e 10 microliter sample size e Routine operation on micro samples of any biological solution including whole blood serum plasma urine and sweat as well as complex specimens such as tissue samples e None of the measurement artifacts that arise in freezing point depression measurements due to elevated viscosity particulate matter inhomogeneities or other physical characteristics of the sample e Superior reliability because the measurement involves minimal mechanical complexity NOTE Vapro displays in Standard International SI units mmol kg See Appendix E SECTION 1 INTRODUCTION 1 4 How the Vapro Works A 10 microliter specimen is aspirated into a micropipettor tip The specimen is then inoculated into a solute free paper disc in the sample holder whereupon the sample holder is pushed into the instrument and the sample chamber is locked Locking initiates the automatic measurement sequence The sensing element is a fine wire thermocouple hygrometer This is suspended in a unique all metal mount which when joined with the sample holder forms a small chamber enclosing the specimen As vapor pressure equilibrates in the chamber airspace
50. lality AC 062 Sample Holder 7 mm dia x 1 25 mm deep supplied with instrument AC 063 Sample Holder 4 25 mm dia x 1 2 mm deep low sample volume SPECIAL PURPOSE SAMPLE HOLDERS gross samples AC 064 Sample Holder 7 mm dia x 2 5 mm deep AC 065 Sample Holder 9 5 mm dia x 4 5 mm deep AC 078 Sample Holder for Kwikdisk models 5520 5500 5100C OSMOMETRY STANDARDS CONTROLS OPTIMOL AMPULE STANDARDS 0 4 mL vial package of 60 OA 010 Optimol Osmolality Standard Solution 100 mmol kg OA 029 Optimol Osmolality Standard Solution 290 mmol kg OA 100 Optimol Osmolality Standard Solution 1000 mmol kg OSMOLALITY CONTROLS 55 025 Osmocoll I Standard Control 1 mL vial package of 6 73 APPENDIX B Accessories Supplies and Replacement Parts SUPPLIES SS 003 Cleaning Solution for manual cleaning 2 oz dropper bottle SS 006 Deionized Water 2 oz dropper bottle SS 026 Blow Clean SS 028 Kwikdisk aluminum paper disks package of 200 requires AC 078 SS 033 Sample Discs vial of 5000 SS 036 Micropipettor Disposable Tips for AC 037 package of 1000 REPLACEMENT PARTS CIRCUIT MODULES and ASSEMBLIES RP 170 Front Panel Keyboard Assembly 310300 Display Assembly 310354 Chamber Switch Assembly 330915 Power Supply Board Assembly 330915X Power Supply Board Assembly with exchange 340454 Main Board Assembly 340454X Main Board Assembly with exchange 310346 Head Cable Assembly FACTORY SERVICE FS 255 Thermocouple Clean and Check
51. le AMBIENT TEMPERATURE AT DEW POINT TEMPERATURELI DEPRESSION WET BULB TEMPERATURE DEW POINT TEMPERATURE 4 PRE CONVERGENCE TEMPERATURE Typical curve for closed chamber ie 0 Um DE 6 a E H n fa 1 2 i3 4 EQUILIBRATION COOLING CONVERGENCE READOUT SAMPLE HOLD i i HJ gt n n TIME SECONDS 0 n 56 69 CHAMBER CLOSED APPENDIX Theory of Operation THERMOCOUPLE TEMPERATURE VERSUS OSMOLALITY The graph on the left is a plot of thermocouple temperature versus time as the instrument cycles through the program beginning with chamber closure time 0 The graph depicts the excursion of thermocouple temperature that typically occurs during each of the program steps outlined above T is the ambient temperature in the chamber Tp is the dew point temperature and AT is the dew point temperature depression The output is proportional to AT Assuming that the chamber remains closed while the osmometer displays the final reading at Step 4 the thermocouple temperature returns to T after holding at the wet bulb depression temperature until all of the water has evaporated from the thermocouple If the chamber is opened the water will evaporate almost instantly and the thermocouple temperature will quickly return to ambient The relationship between sample osmolality and the reading obtained by the osmometer is governed by fundamental considera ti
52. lligative property of a solution but unlike the other three it is not a cardinal property of the solvent Solution osmotic pressure can be measured directly using a semi permeable membrane apparatus but only with respect to those solute particles that are impermeable since smaller solute particles freely transude the membrane and do not directly contribute to osmotic pressure Such a measurement is referred to as colloid osmotic pressure or oncotic pressure It is expressed in terms of pressure in mmHg or kPa Total osmotic pressure i e that which can be calculated on the basis of total solute concentration is a the oretical concept only The measurement of total solution concentration or osmolality can only be made indirectly by comparing one of the solution colligative properties with the corresponding cardinal property of the pure sol vent The first practical laboratory instruments developed for routine measurement of osmolality were based upon depression of the freezing point and until recent years all osmometers for large scale testing were based upon this methodology 75 APPENDIX C Theory of Operation The Vapro osmometer embodies newer technology It is based upon a measurement of vapor pressure depression made possible by thermocouple hygrometry The vapor pressure method enjoys a sig nificant intrinsic advantage over the measurement of either freezing point depression or boiling point elevation in that it can b
53. mometer on a suitable work sur face NOTE Avoid locations where instrument precision will be altered by thermal gradients or rapid temperature changes caused by heavy foot traffic air vents blow ers heaters or windows 2 Connect the power cord to an electrical outlet that matches the voltage selected on the rear panel Avoid power circuits that are shared by centrifuges air conditioners or other power equipment We recommend that you use a power line surge protector to isolate the osmometer from spikes and surges 3 Verify that the sample holder is in the measure ment position sample slide is pushed com pletely into the instrument until it stops Verify that the sample chamber lever is in the closed position TURN PAGE TO CONTINUE INSTRUCTIONS 19 SECTION 2 GETTING STARTED 2 3 Setting Up the Osmometer Turn the osmometer on I The POWER indica tor on the front panel shows green when power is on The display screen will briefly show the Wescor logo language and unit selection and the resident software version This will be followed by the word initialization with a countdown timer To change the diplayed language or units of mea sure see Appendix G Setup Menu Chamber Empty NOTE If you open the chamber lever before the end of the ini R F A gt tialization cycle the warning chime sounds The initialization cycle establishes the reference point for the instrument W
54. nt varies with the solute con centration the relation between osmolality and concentration of solute is not linear For this reason measurements of osmolality made on laboratory diluted specimens with subsequent multiplica tion by the dilution factor to calculate the original solution osmolality will not give valid results 91 APPENDIX E Osmolality Standards With complex solutions such as biological fluids analytical vari ables are universally expressed as the concentration of specific ions and of undissociated solute particles It follows that a molal solution of NaCl can be analytically expressed as a combination of a molal solution of sodium ions and a molal solution of chloride ions The total concentration of solute particles the osmolality is therefore 2000 millimolal Osmolality can best be expressed simply as 2000 mmol kg without the necessity of introducing the osmole concept The commission on Clinical Chemistry of the International Union of Pure and Applied Chemistry IUPAC and the International Federation of Clinical Chemistry IFCC have recommended that the unit of osmolality be mmol kg and this has been adopted by the American Journal Clinical Chemistry as part of its general accep tance of Standard International units Wescor led the industry as the first osmometer manufacturer to adopt Standard International SI units for osmolality QUALITY ASSURANCE Wescor calibration solutions are manufactured using
55. oltmeter reads the amplifier voltage to establish the reference for the measurement 76 APPENDIX Theory of Operation PROGRAM STEP 2 COOLING An electrical current is passed through the thermocouple cooling it by means of the Peltier Effect to a temperature below the dew point Water condenses from the air in the chamber to form microscopic droplets upon the surface of the thermocouple PROGRAM STEP 3 DEW POINT CONVERGENCE Electronic circuitry pumps thermal energy from the thermocouple via Peltier cooling in such a way as to cancel out heat influx to the thermocouple by conduction convection and radiation Given this the temperature of the thermocouple is controlled exclusively by the water condensing upon its surface Thermocouple temperature depressed below the dew point in Step 2 rises asymptotically toward the dew point as water continues to condense When the temperature of the thermocouple reaches the dew point condensa tion ceases causing the thermocouple temperature to stabilize PROGRAM STEP 4 END OF SEQUENCE AND READOUT The reading on the display is proportional to the vapor pressure of the solution When this final reading is reached a chime sounds and the In Process changes to Osmolality The result is displayed in SI units of osmolality mmol kg 77 APPENDIX C Theory of Operation 78 THERMOCOUPLE TEMPERATURE THERMOCOUPLE TEMPERATURE VS TIME with 290 mmol kg samp
56. ons Vapor pressure depression a linear function of osmolality has been identified as one of the colligative properties of a solution The relationship between vapor pressure depression and dew point tem perature depression is given by AT Ae S where AT is the dew point temperature depression in degrees Celsius Ae is the difference between saturation and chamber vapor pressure and S is the slope of the vapor pressure temperature func tion at ambient temperature The Claussius Clapeyron equation gives S as a function of temperature T saturation vapor pressure and latent heat of vaporization A S Eo RT where R is the universal gas constant The dew point temperature depression AT is measured as a volt age signal from the thermocouple This voltage is equal to AT mul tiplied by the thermocouple responsivity which is approximately 62 microvolts per degree Celsius After voltage amplification by a pre amplifier the signal is processed by the microprocessor to provide calibrate and compensate functions and display the reading 79 APPENDIX D Special Application Notes Clinical and General Research The Vapro osmometer has unique advantages in many aspects of clini cal chemistry due to its very small sample requirement This is particu larly true in pediatric practice For example the amount of sample col lected for sweat fecal sputum duodenal and gastric analysis is fre quently too small to allow osmolal
57. or experimental purposes large volume sample holders are available These sample holders will accommodate gross specimens that are not amenable to testing with the standard shallow sample holder Contact Wescor for more information 81 APPENDIX D Special Application Notes PROCEDURE FOR VERY SMALL SAMPLES You can measure samples with very low volumes under 4 uL using the following procedures Sample discs must be hand made from high grade filter paper Whatman 1 or equivalent using a high precision 1 8 inch diame ter paper punch to produce discs with a very clean edge Required Equipment e Wescor low volume sample holder AC 063 e High quality round hole paper punch 1 8 diameter Mieth or equivalent e High quality 2 pL pipette which will deliver precisely 2 microliters or less e Pipette tips short e Tweezers e Teasing needle e Whatman 1 Filter Paper or equivalent e Lint free tissue paper e Cotton tipped applicators NOTE Maintain a stable ambient temperature Heat cold air currents and temper ature fluctuations which vary more than approximately 0 3 C within a 10 to 15 minute time frame generally will result in poor quality data You should monitor the Temp Drift Scale for ambient temperature fluctuations which will interfere with instrument accuracy Technique including timing is vitally important to obtaining good data while conducting very low volume tests 82 APPENDIX D Specia
58. possible sources of thermal disturbance as outlined in Section 2 3 Use AUTO REPEAT to evaluate the precision of the osmometer Run the instrument with 1000 mmol kg standard in AUTO REPEAT to determine if instrument can repeat well If it does consider the possibility of loading errors causing poor repeatability SECTION 5 SOLVING PROBLEMS 5 4 Deformed or Broken Thermocouple The thermocouple is well protected while the TC head is in the instrument Cleaning procedures detailed in this manual should not harm the thermo couple but it can be deformed or broken if contact ed by any object while it is out of the instrument e f the thermocouple is only slightly deformed the instrument will automatically adjust for the deformed thermocouple and function normally e Abadly deformed thermocouple will still function but will show a noticeable loss of measurement precision e Adeformed or flattened thermocouple with its bead lying close to or touching the surface of the mount will not cool to normal temperature depression during the measurement cycle Appendix C As a result the instrument may display a meaningless value Restoring a Deformed Thermocouple You can usually salvage even a severely deformed thermocouple by carefully lifting it into normal posi tion Although the thermocouple wires are only 0 025 mm in diameter they are quite malleable and are generally amenable to straightening and reshaping In any
59. r cord and switch power on Allow for temperature equilibration observe Temperature Drift Scale 5 Practice loading samples 6 Perform a Clean Test and clean the thermocouple if necessary 7 Check instrument calibration and recalibrate if necessary 8 Assay samples 50050 oo LIL I SECTION 2 GETTING STARTED 2 2 Vapro Accessories The following accessories and supplies are furnished with the Vapro osmometer Vapro User s Manual Micropipettor Micropipettor Disposable Tips Forceps Paper Sample Discs Optimol Osmolality Ampule Standards Osmocoll Osmolality Serum Control Ampule Organizer 9 64 inch Hex Driver Thermocouple Head Cleaning Supplies consisting of Cleaning Solution Deionized Water Blow Clean U S 48 states only In addition to the above you need a supply of lint free tissue paper or cotton swabs for cleaning the sample holder between specimens CAUTION Never use facial or other soft tissue to clean the sample holder Such tissues produce excessive lint residue that will contaminate the thermo couple sensor Compressed or liquefied pure gas suitable for blowing dust from delicate surfaces or precision mechanisms Available under various trade names 18 SECTION 2 STARTED 2 3 Setting Up Osmometer Carefully unpack the instrument and compare the contents with the packing list to be certain that everything needed for operation is at hand 1 Place the os
60. reference data on the concentrative properties of sodium chloride in water from the Handbook of Physics and Chemistry CRC Press For quality assur ance each lot is compared by replicate osmolality measurements to reference solutions prepared from dried high purity sodium chloride obtained from the National Institute of Standards and Technology NIST Wescor guarantees the accuracy of its calibration solutions within the combined overall accuracy of the reference solution formula tions and the control measurements 100 2 mmol kg 290 3 mmol kg 1 000 5 mmol kg 92 APPENDIX F Serial Data Output The 5520 serial port uses a DB9 connector on the instru ment back panel This port is for asynchronous serial com munication with a printer or computer It uses standard non return to zero NRZ format at RS 232 voltage levels The 5520 checks to see if the RTS pin 7 is active When a sample is assayed while a device is connected to the 5520 s RS 232 port the display status line will show ENTER to Send To send data to the external device press ENTER The display will show Osmolalitu SERIAL OUTPUT TECHNICAL DATA Output voltage level Nominal 9 volts Maximum 15 volts Minimum 5 volts Data protocol 1200 bps 1 Start bit 8 Data bits No parity 1 Stop bit 93 APPENDIX F Serial Data Output Pin Diagram Pin Mnemonic Description f 1 DCD Data Carrier Detect output Pint 2 3 4 5 2 RXD Re
61. rom Wescor if needed Refer to Section 1 2 67 SECTION 5 SOLVING PROBLEMS 5 3 External Factors Affecting Precision 68 Problems with instrument precision have a number of possible sources Often poor reproducibility is caused by external factors that are entirely independent of the instrument itself The following are some of these factors e Incorrect Use of Calibration Standards Instrument accuracy and linearity depend upon the correct use of osmolality calibration standards Refer to Section 2 5 2 6 and Appendix E for further information Sampling Error Sampling error tends to be amplified when dealing with specimens of 10 microliters or less You can prevent errors by using consistent technique and appropriate methods of transfer ring samples See Section 3 2 for details Micropipettor Caused Errors Unlike the maintenance free micropipettor supplied by Wescor many micropipetting devices require routine maintenance Without proper maintenance micropipetting devices can exhibit significant volumetric error in excess of 50 and cause corresponding variations in indicated osmolality Positive displacement micropipettors are not recommended as an alternative to the Wescor micropipettor except when dealing with samples of very high viscosity e Poor Precision Determine whether the problem is with the instrument or is caused by external factors such as the micropipettor Check the location of the osmometer for
62. s 9 cycle 10 15 20 31 43 errors 21 position 19 range 71 reference point 10 repeatability 71 resolution 71 sequence 10 time 71 86 units 20 101 Menu Function 29 31 Mode 29 30 42 selection 29 Micropipetting technique 23 35 36 errors 68 Micropipettor 18 21 positive displacement 21 88 three step 21 two step 21 tip 10 18 21 35 36 Mode s Auto Repeat 31 Average 30 Menu 29 changing 29 selecting 29 Normal 30 Process Delay 31 Standby 15 21 29 38 43 Multi solvent Solutions measuring 89 N Nonhomogeneous Samples 88 O Optimol Osmolality Standards 18 24 58 59 evaporation 25 opening 24 Osmocoll 1 Osmolality Control Reference 18 26 control value 26 refrigerating 26 Osmolality 75 display 37 58 59 93 on empty chamber 43 range 26 readout 71 standards 18 24 25 58 59 64 68 92 Osmometry boiling point 76 77 89 freezing point 75 77 89 90 vapor pressure 75 77 89 90 Osmotic pressure 75 p Packing List 19 P Paper punch 82 Paper Sample Disc s 10 18 35 36 39 75 for special applications 82 83 84 86 measuring without 88 Pipette guide 12 13 36 tip 10 35 special purpose 82 Particles solute 75 Power connecting 19 60 consumption 71 cord 16 19 indicator 12 13 19 58 60 Entry Module 14 16 switch 16 46 52 58 Surge Protector 19 Preventive Maintenance 45 Process Delay Mode 31 85 Properties cardinal 75 Protection Sleeve 24 R Radio opaque media 81 Replacemen
63. s must be interpreted accordingly 89 APPENDIX D Special Application Notes You must be aware of this phenomenon if you are to correctly inter pret results By way of illustration the table below depicts the results of solution osmolality measurements made by both vapor pressure and freezing point osmometers for varying amounts of ethanol in human blood serum Note that in the vapor pressure instrument concentrations of ethanol anywhere within the clinically significant range do not appreciably affect the indication of osmolali ty This is because the vapor pressure of a water ethanol solution does not change measurably with small concentrations of ethanol On the other hand the freezing point osmometer tends to overesti mate the actual number of ethanol particles in the solution as the freezing point falls disproportionately with increasing amounts of ethanol Thus neither instrument faithfully reports osmolality in the case of water ethanol mixtures In clinical practice the unique response of the vapor pressure osmometer is usually an advantage inasmuch as it allows the clinician or attending physician to monitor the patient s serum metabolites other than alcohol independently of the patient s blood alcohol level TABLE ETHANOL IN HUMAN BLOOD SERUM VAPOR PRESSURE VERSUS FREEZING POINT OSMOLALITY DETERMINATION 1 2 2 2 Calculated Measured Measured Serum Ethanol Ethanol Ethanol Total V P Osmolality Added kg
64. s or samples as small as 2 pL can be measured reliably with special procedures Measurement Range Typically 0 to 3200 mmol kg 25 C ambient Measurement Time 80 seconds Resolution 1 mmol kg Repeatability Standard deviation lt 2 mmol kg Linearity 2 of reading from 100 to 2000 mmol kg Readout 10 X 6 8 cm LCD Operating Temperature 15 to 37 C ambient instrument should be at stable temperature before calibrating Calibration Automatic using Optimol osmolality standards Serial Output RS 232 ASCII format Electrical Line Voltage 100 to 120 V or 220 to 240 V nominal set at factory user selectable with fuse change 50 to 60 Hz Power Less than 5 watts Fuses 1 8 ampere 1 4 x 1 1 4 time delay type for 100 to 120 volts 2 required 1 16 ampere 1 4 x 1 1 4 time delay type for 220 to 240 volts 2 required Size Height 17 cm 6 6 Width 29 cm 11 5 Depth 34 cm 13 5 Weight 3 6 kg 8 Ibs mmol kg is the Standard International SI unit of osmolality Refer to Appendix E 71 APPENDIX B Accessories Supplies and Replacement Parts ACCESSORIES AC 037 Micropipettor 10 microliter AC 061 Ampule Organizer AC 066 Thermocouple Head Assembly model 5520 0 to 3200 mmol kg AC 067 Thermocouple Head Assembly model 5520 above 3200 mmol kg OM 275 Hex Driver 9 64 screwdriver handle OM 300 Forceps 5 inch stainless steel STANDARD SAMPLE HOLDERS for solution osmo
65. t Parts 67 73 Reproducibility 68 RS 232 15 93 S Sample s Chamber 10 52 76 lever 14 35 37 39 51 99 5 Sample s complex 31 81 89 holder 10 12 35 36 45 cleaning 39 45 63 84 special purpose 81 82 leaf disc 85 loading 34 35 59 82 84 mutiphasic 81 nonhomogeneous 88 physical characteristics 9 81 89 slide 12 13 19 solid s 85 tissue 81 85 very small 82 very large 85 viscosity 9 81 volume 23 71 large 85 87 very small 83 4 variations in 34 Sampling Error 68 Screen see display screen SELECT Keypad 12 13 32 40 42 Sensing Element 10 Serial Data output 44 93 94 pin diagram 94 Port 14 15 44 93 94 voltage data 93 Signal Chime 14 37 77 shutter wheel 15 Software resident version 20 Solute Particles 9 Solution colligative properties of 9 76 concentration 9 75 see also osmolality 100 Special Applications 81 90 Clinical and General Research 81 Specimen feces 81 gastrointestinal aspirate 81 physical state 9 removing 38 sputum 81 sweat 81 Standard Deviation 30 59 62 Standard International Units 9 38 71 77 91 Swab Stick 55 T Teasing needle 82 Temperature ambient 10 20 21 43 71 considerations during setup 19 dew point 10 Drift Scale 20 21 53 60 61 82 stability 58 67 82 Thermal Equilibration 20 21 52 53 60 67 76 85 Theory of Operation 75 79 Thermocouple TC cleaning 40 45 50 55 56 cooling 77 control circuitry 43 contamination 18 21 31
66. ter running a sample before opening the chamber Select Average Mode and press ENTER The last sample assayed will be 1 in the data group SECTION 3 5 3 1 Operation Overview Auto Repeat Mode Checks the repeatability of the osmometer on the Sensor Dpuaind same sample The instrument will automatically run 999 Lk 10 consecutive measurements on the sample usu nma 3 ally a 1000 mmol kg Optimol sample and display the statistical data Since the chamber is not opened between measurements as in other modes a short delay occurs between each measurement while water evaporates from the thermocouple During this time the display screen shows Sensor Drying Low osmolality samples below 200 mmol kg may show a difference between the first any subse quent readings if the chamber is contaminated see 998 mmaol ks Section 3 4 Sample 3 Mean The Auto Repeat sequence can be interrupted at pun any point simply by opening the sample chamber Auto Repeat Mode Process Delay Mode Complex samples such as leaf and other samples from which water may not readily evaporate require long periods to reach vapor equilibrium Process Process Delay Delay Mode delays the measurement cycle after you 1 mmol ka close the chamber until you press ENTER In research applications this lets you delay measure Press ENTER ment until vapor equilibrium is achieved The m
67. terials For these more difficult situations try cleaning agents such as acetone or a laboratory detergent such as Alconox To remove deposits 1 Apply cleaning agents using the methods described in Section 4 3 2 Cut a wooden swab stick on a sharp angle to form a fine point 3 Scrub the surface of the mount with the swab stick and rinse Performed under the microscope this procedure is unlikely to damage to the thermocouple itself With patience and repeated use of cleaning agents even the most severely contaminated thermocouple can be cleaned 55 SECTION 4 PREVENTIVE MAINTENANCE 4 6 Severe or Stubborn Contamination To clean dark or corroded copper connection points 1 Apply a droplet of concentrated ammonium hydroxide NH4OH 28 to 30 to the TC mount Soaking with this solution for a few minutes will reduce oxidation and restore the bright copper color 2 Rinse the thermocouple with pure water 56 SECTION 5 SOLVING PROBLEMS 5 1 Troubleshooting This section describes problems you might encounter in using the Vapro osmometer with suggested solutions The first part is a flow chart to help you identify problems by symptom Beginning with the apparent symptom trace through the flow chart to identify possible causes and solutions for the difficulty Each set of symptoms and solutions is repeated and discussed in greater detail in the following pages of Section 5 1 The solutions are indexed to more
68. the thermo couple senses the ambient temperature of the air thus establishing the reference point for the measurement Under electronic control the thermocouple then seeks the dew point temperature within the enclosed space giving an output proportional to the differential tem perature The difference between the ambient temperature and the dew point temperature is the dew point temperature depression an explicit function of solution vapor pressure Dew point temperature depression is measured with a resolution of 0 00031 C The microprocessor controlled measurement cycle requires 80 seconds Appendix C contains the theory of operation of the vapor pressure osmometer 10 Head Thermocouple and TC Mount Connector Thermocouple Head and Sample Chamber Assembly 11 Sample Slide Sample Holder Head Access Cover Press to Remove Cover Pipette Guide Display Screen Gazer Power Indicator SELECT Keypad ENTER Keypad 12 SECTION 1 INTRODUCTION 1 5 Controls and Features INSTRUMENT FRONT PANEL Display Screen 10 x 7 cm LCD Displays menu selections osmolality readings countdown of measurement time in seconds operating status fault conditions and other information SELECT Keypad Press to call up menus and to select operation mode ENTER Keypad Press to engage a selected menu item or operation mode Pipette Guide
69. uccessful results have been achieved using standard labora tory lint free tissue 83 APPENDIX D Special Application Notes Instructions 1 Calibrate the instrument using 2 pL of standard 2 Load a single paper disc into the center of the special sample holder You may need to use the teasing needle and the tweezers to separate discs that stuck together 3 Place sample into the center of paper disc Be sure to touch the pipette onto the disc as in regular procedure Be sure the disc is completely saturated 4 Close the sample chamber to begin the measurement cycle 5 When the measurement is complete open the sample cham ber and retract the sample slide 6 Thoroughly clean the sample holder of all sample material using lint free tissue and a cotton tipped applicator 84 APPENDIX D Special Application Notes MEASURING LARGE SAMPLES Measuring large samples requires consideration of the nature and size of the sample You should experiment with these procedures to find the best approach for your particular application Samples such as leaf discs tissues and other solids often require considerable time to reach equilibrium The Process Delay Mode allows you to delay the measurement indefinitely or to take succes sive readings without opening the chamber The time required to achieve equilibration can be determined by taking measurements until the readings no longer decrease Once you become familiar w
70. us on its surface SECTION 3 OPERATING THE VAPRO OSMOMETER 3 2 Loading Samples Gently push the sample slide into the instru ment until it stops Never close the chamber unless the sample holder is in this position 8 Grasping the sample chamber lever between thumb and forefinger rotate it smoothly to the closed position NOTE Since the sample may concentrate slightly before the chamber is sealed steps 5 through 8 should be performed with consistent timing A warning chime sounds If the chamber is left open longer than 2 minutes Closing the lever starts the measurement cycle The display screen shows In Process and counts down the remaining time in Process seconds When the measurement is completed the chime sounds The display screen shows the osmolality of the specimen zmolalitu 227 nnolzka 37 SECTION 3 OPERATING THE VAPRO OSMOMETER 3 2 Loading Samples The display shows this final reading until the cham ber is opened and closed once again NOTE Vapro reports osmolality measurements in Standard International SI units mmol kg CAUTION During long uninterrupted measurement periods occasionally allow the instrument to return to the standby mode by initiating an operating cycle on an empty chamber This is necessary for the instrument to readjust itself to any temperature change that may have occurred during the interval Failure to do th
71. ussius Clapeyron equation 79 Clean Test 32 34 39 40 45 50 52 54 58 61 Colligative properties 9 75 89 Contamination see Thermocouple Customer Service 8 D Delete Result Function 33 Dew Point Convergence 77 Dew Point Temperature 10 Dew Point Temperature Depression 10 79 Display abnormal 63 blank 60 language 20 101 screen 9 12 20 34 36 37 40 42 58 61 64 77 93 94 units 20 101 E Electronic Malfunction 67 70 ENTER Keypad 12 13 40 42 44 85 86 93 94 Equilibration see thermal equilibration Erratic Readings 59 70 Error Message s 58 59 61 63 64 Ethanol in Human Blood Serum 90 F Facial Tissue 18 Feces 81 Filter Paper 82 85 Forceps 18 97 Function Calibrate 32 33 41 42 Clean Test 32 Delete Result 33 Menu 29 32 42 Fuse s 16 changing 28 door 16 28 specifications 28 71 H Hex Driver 18 47 Human Blood Serum 90 Hygrometric Method 9 I Initialization cycle 20 Inhomogeneities 9 In Process Display 37 Instrument dimensions 71 front panel 13 interior 15 moving 21 precision 65 68 rear panel 16 response characteristics 41 right side 14 15 setup 17 specifications 71 weight 71 International Attention Symbol 9 93 K Keypad s ENTER 12 13 29 31 32 42 44 86 87 93 94 SELECT 12 13 29 32 42 98 L Language changing 20 95 display 20 95 Linearity in low range 61 62 66 Line Voltage 71 M Malfunction see Electronic Measurement artifact
72. visible to the eye even if the thermocouple appears to be clean it may not give an acceptable clean test Section 3 4 In this case follow the instructions in Section 4 6 3 Check if the thermocouple has been deformed or broken Refer to Section 5 4 for information on identifying thermocouple deformation and how to restore it to normal shape 4 Inspect the TC head connector and the mating pins for distortion or misalignment 66 SECTION 5 SOLVING PROBLEMS 5 2 Common TC Head Problems NOTE Always switch power off before connecting or disconnecting the TC head If the connector is damaged electrical connection may be compro mised or fail altogether A failed connection produces an ERROR message on the display as with a broken thermocouple A poor connection can cause erratic performance If the source of difficulty is still unknown at least the most frequently occurring problems will have been eliminated Testing Osmometer Performance 1 Reinstall the TC head to continue troubleshooting 2 Set the instrument up using the procedure outlined in Section 3 3 Allow 30 minutes for thermal equilibrium 4 If you have a problem performing any of the steps of the setup procedure a malfunctioning electronic module is likely Contact Wescor or your dealer for assistance Replacement parts are available for user installation or the entire instrument can be returned to Wescor for repair Loan instruments are available f

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