Manual - Hach DPD Indicator Powder
Contents
1. Chlorine Free DOC316 53 01026 DPD Rapid Liquid Method Method 10059 0 02 to 2 00 mg L Pour Thru Cell Scope and Application For treated water 1 Adapted from Standard Methods for the Examination of Water and Wastewater Test preparation How to use instrument specific information The nstrument specific information table displays requirements that may vary between instruments To use this table select an instrument then read across to find the corresponding information required to perform this test Table 98 Instrument specific information Instrument Pour thru Kit Cell orientation Adapter DR 6000 LQV175 99 20002 Arrow faces right DR 5000 LZV479 _ DR 3900 LQV157 99 10002 PEA oh arrows with arrows on cell 5940400 1 inch round path in line with the arrow on LZV585 B DR 3800 DR 2800 DR 2700 the adapter Before starting the test Analyze samples immediately Do not preserve for later analysis Refer to the instrument User Manual for Pour Thru cell and module assembly and installation Protect the Pour Thru Cell from contamination when not in use by inverting a small beaker over the top of the glass funnel The indicator reagent must be prepared in advance See Reagent preparation Make sure the pour thru cell is completely seated in the sample cell compartment Collect the following items Description Quantity DPD Indicator Powder varies Free Chlorine Indicato2. mL 16 pkg 1426810 OR Chlorine Standard Solution Pour Rite Ampule 50 75 mg L 2 mL 20 pkg 1426820 Voluette Ampule breaker 10 mL each 2196800 PourRite Ampule breaker 2 mL each 2484600 Water deionized 4L 27256 Optional standards and apparatus Description Unit Catalog number Pipet TenSette 0 1 1 0 mL each 1970001 Pipet Tips for TenSette Pipet 1970001 50 pkg 2185696 Pipet Tips for TenSette Pipet 19700011 1000 pkg 2185628 pH Paper 0 14 pH range 100 pkg 2601300 Potassium lodide 30 g L 100 mL 34332 Sodium Arsenite 5 g L 100 mL 104732 Sulfuric Acid 1 N 100 mL 127032 Sulfuric Acid 5 25 N 100 mL 244953 1 Other sizes are available FOR TECHNICAL ASSISTANCE PRICE INFORMATION AND ORDERING HACH COMPANY In the U S A Call toll free 800 227 4224 Outside the U S A Contact the HACH office or distributor serving you On the Worldwide Web www hach com E mail techhelp hach com Hach Company 2007 2010 2012 All rights reserved Printed in the U S A WORLD HEADQUARTERS Telephone 970 669 3050 FAX 970 669 2932 Edition 7
3. ll Chlorine Free Page 4 of 6 The Pour Thru Cell may accumulate a buildup of colored reaction products especially if the reacted solutions are allowed to remain in the cell for long periods after measurement Remove the buildup by rinsing the cell with 5 25 N Sulfuric Acid followed by several rinsings with deionized water Chlorine Free Accuracy check Required for accuracy check e Chlorine Voluette Ampule Standard Solution 50 to 75 mg L Clp e TenSette Pipet and tips Standard additions method sample spike 1 After reading test results leave the sample cell unspiked sample in the instrument 2 Select Options gt More gt Standard Additions from the instrument menu 3 Default values for standard concentration sample volume and spike volumes can be accepted or edited Enter the chlorine concentration from the ampule package After values are accepted the unspiked sample reading will appear in the top row See the user manual for more information 4 Open a Chlorine Voluette Ampule Standard Solution 50 to 75 mg L Clo 5 Prepare three sample spikes Use the TenSette Pipet to add 0 3 0 6 and 0 9 mL of standard to three 80 mL samples respectively Swirl gently to mix 6 Analyze each sample spike as described in the procedure above starting with the 0 3 mL sample spike Accept each standard additions value Each addition should reflect approximately 100 recovery 7 After completing the sequence press GRAPH to vie
4. lo Interferes at all levels See Required reagents Chlorine Free Page 3 of 6 Chlorine Free Table 99 Interfering substances continued Interfering substance Interference level 1 Adjust sample pH to 6 7 with 1 000 N Sulfuric Acid 2 Add 9 drops Potassium lodide 30 g L to an 80 mL sample Manganese oxidized Mn4 3 Mix and wait 1 minute Mn7 or Chromium oxidized 4 Add 9 drops Sodium Arsenite 2 5 g L and mix Cr 5 Analyze the treated sample as described in the procedure above 6 Subtract the result of this test from the original analysis to obtain the correct concentration Samples containing monochloramine will cause a gradual drift to higher chlorine readings Monochloramine NH2Cl When read within one minute of reagent addition 3 0 mg L monochloramine will cause an increase of less than 0 1 mg L in the free chlorine reading Ozone Interferes at all levels 1 See Optional standards and apparatus 2 Samples treated with sodium arsenite for interferences will be hazardous waste as regulated by the Federal RCRA for arsenic D004 Refer to the current MSDS for safe handling and disposal instructions Sampling and storage Samples must be analyzed immediately and cannot be preserved for later analysis A common testing error is introduced if the analyst does not obtain a representative sample If sampling from a tap let the water flow for at least five minutes to ens
5. r Solution 1 mL Free Chlorine Buffer Solution 1 mL Cylinder glass mixing 100 mL 1 Dispenser Adjustable Volume 2 Pour Thru Cell Module and Cell see nstrument specific information 1 See Consumables and replacement items for reorder information Chlorine Free Page 1 of 6 Chlorine Free Free Chlorine rapid liquid method Stored Programs 82 Chlorine F amp T RL Start 1 Select the test See Instrument specific information 5 Add 1 0 mL of Free Chlorine Buffer Solution to a clean dry 100 mL glass mixing cylinder using the Dispenser Chlorine Free Page 2 of 6 2 Install the Pour Thru 3 Pour approximately 4 When the flow stops Cell module and cell See 50 mL of sample into the press ZERO The display Instrument specific Pour Thru Cell will show 0 00 mg L Clo information for adapter and cell orientation rw 6 Add 1 0 mL of 7 Carefully fill the mixing 8 Stopper the cylinder prepared Free Chlorine cylinder to the 80 mL mark and gently invert it twice to Indicator Solution to the with sample mix Proceed to step 8 same mixing cylinder immediately using the dispenser Swirl to mix the reagents Proceed to step 7 immediately Chlorine Free Free Chlorine rapid liquid method continued oo Read 9 Fill the funnel of the 10 After the flow stops Pour Thru Cell with the press READ Results will reacted sample from the appear in mg L Clo mixing cylinder It is not neces
6. sary to pour the entire sample into the Pour Thru Cell approximately half of the sample may be discarded Reagent preparation 11 Flush the Pour Thru Cell with at least 50 mL of deionized water immediately after use The Free Chlorine Indicator Solution must be prepared before use Using a powder funnel add the contents of one 24 g bottle of DPD Powder to one 473 mL bottle of Free Chlorine Indicator Solution Invert several times and swirl until the powder is completely dissolved A pale pink color may develop but should not affect results This solution will give accurate results for at least one month after mixing when stored at 20 25 C 68 77 C Write the date of preparation on the Indicator Solution Bottle Discard any remaining solution after one month Use of this reagent after one month may result in high reagent blanks and low values at high concentration Do not combine fresh reagent with previously mixed reagent Interferences Table 99 Interfering substances Interfering substance Interference level Greater than 400 mg L CaCO3 May not develop full color or color may fade instantly Alkalinity Neutralize to pH 6 7 with 1 N Sulfuric Acid Determine amount to be added on separate sample aliquot then add the same amount to the sample being tested Correct for volume addition Bromine Bro Interferes at all levels Hardness Levels below 1000 mg L as CaCO4 will not interfere lodine
7. ure a representative sample Let the container overflow with the sample several times then cap the sample container so there is no headspace air above the sample Perform the chlorine analysis immediately Avoid plastic containers since these may have a chlorine demand Pre treat glass sample containers to remove any chlorine demand by soaking in a dilute bleach solution 1 mL commercial bleach to 1 liter of deionized water for at least 1 hour Rinse thoroughly with deionized water If sample containers are rinsed thoroughly with deionized water after use only occasional pretreatment is necessary A pre treated glass BOD bottle with a ground glass stopper makes an ideal sample container for chlorine collection Treating analysis labware Glassware used in this test must be chlorine demand free Fill the 100 mL mixing cylinder and sample container with a dilute solution of chlorine bleach prepared by adding 1 mL of commercial bleach to 1 liter of water Soak in this solution at least one hour After soaking rinse thoroughly with deionized water and allow to dry before use If the mixing cylinder is thoroughly rinsed with deionized water and allowed to dry after each use only occasional pretreatment is necessary Do not use the same mixing cylinder for Free and Total Chlorine analysis Treat the Pour Thru Cell similarly with dilute bleach and let stand for several minutes Rinse several times with deionized water Cleaning the Pour Thru Ce
8. w the best fit line through the standard additions data points accounting for the matrix interferences Press IDEAL LINE to view the relationship between the sample spikes and the Ideal Line of 100 recovery Method performance Precision Sensitivity Program Standard 95 Confidence Limits of Concentration change Distribution per 0 010 Abs change 82 1 18 mg L Clo 1 17 1 19 mg L Clo 0 02 mg L Clo Summary of method Chlorine in the sample as hypochlorous acid or hypochlorite ion free chlorine or free available chlorine immediately reacts with DPD N N diethyl p phenylenediamine indicator to form a pink color which is proportional to the chlorine concentration Test results are measured at 530 nm Consumables and replacement items Required reagents Description Quantity Test Unit Catalog number Free Chlorine Reagent Set includes 2556900 DPD Indicator Powder varies 24g 2297255 Free Chlorine Indicator Solution 1 mL 473 mL 2314011 Free Chlorine Buffer Solution 1 mL 473 mL 2314111 Chlorine Free Page 5 of 6 Chlorine Free Required apparatus Description Quantity Unit Catalog number Cylinder mixing graduated 100 mL glass 1 each 2636342 Dispenser adjustable volume 1 0 5 0 mL 2 each 2563137 Powder Funnel 1 each 2264467 Recommended standards Description Unit Catalog number Chlorine Standard Solution Voluette Ampule 50 75 mg L 10
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