Method 8033
Contents
1. Call toll free 800 227 4224 WORLD HEADQUARTERS Outside the U S A Contact the HACH office or distributor serving you Telephone 970 669 3050 On the Worldwide Web www hach com E mail techhelp hach com FAX 970 669 2932 Hach Company 2005 All rights reserved Printed in Germany Updated April 05 Edition 12. Eliminate interference from the metals in Table 1 by the following treatment beginning after Step 6 1 Measure about 5 mL of the DithiVer solution into the separatory funnel Stopper the funnel invert and open the stopcock to vent Close the stopcock and shake the solution vigorously for 15 seconds Allow the funnel to stand undisturbed until the layers separate about 30 seconds A yellow red or bronze color in the bottom chloroform layer confirms the presence of interfering metals Draw off and collect the bottom chloroform layer for proper disposal Lead Page 4 of 8 Lead_8033_Dithizone fm Lead 3 to 300 ug L Repeat extraction with fresh 5 mL portions of prepared dithizone solution collecting the bottom layer each time in appropriate waste collection vessel until the bottom layer shows a pure dark green color for three successive extracts Extractions can be repeated a number of times without appreciably affecting the amount of lead in the sample Extract the solution with several 2 or 3 mL portions of pure chloroform to remove any remaining dithizone again collecting the bottom layer each time for proper disposal Continue the procedure substituting 28 5 mL of prepared dithizone solution for the 30 mL in Step 7 DithiVer Solution Preparation Storage and Reagent Blank Store DithiVer Powder Pillows away from light and heat A convenient way to prepare this solution is to add the contents of 10 DithiVer Metals
3. 5 more drops of 5 0 N Sodium Hydroxide Standard Solution A pink color in the bottom chloroform layer at this point does not necessarily indicate lead is present Only after adding the potassium cyanide in the next step will the presence of lead be confirmed by a pink color 15 Blank Preparation Fill another 25 mL square sample cell with chloroform Stopper Lead 3 to 300 ug L 12 Add 2 heaping 1 0 g scoops of potassium cyanide to the funnel Stopper Shake vigorously until the potassium cyanide is all dissolved about 15 seconds 16 Insert the blank into the cell holder with the fill line facing the user Lead Page 3 of 8 Lead 3 to 300 ug L Zero 17 Press ZERO The display will show 0 ug L Pb2 Interferences 18 Insert the prepared sample into the cell holder with the fill line facing the user Results are in ug L Pb 2 Table 1 Interfering Substances and Levels Interfering Substance Interference Levels and Treatments ste ardor ples or All levels See procedure below Bismuth All levels See procedure below Copper All levels See procedure below Mercury All levels See procedure below Silver All levels See procedure below Tin All levels See procedure below Table 2 Substances That Do Not Interfere Aluminum Lead Antimony Magnesium Arsenic Manganese Calcium Nickel Chromium Tin Cobalt ion Zinc
4. Lead X Method 8033 Dithizone Method Powder Pillows 3 to 300 pg L Scope and Application For water and wastewater USEPA accepted for reporting for wastewater analysis digestion is required 2 1 Adapted from Snyder L J Analytical Chemistry 19 684 1947 2 Procedure is equivalent to Standard Method 3500 Pb D for wastewater analysis Before starting the test For more accurate results determine a reagent blank value for each new lot of reagent Follow the procedure using deionized water instead of the sample Clean all glassware with a 1 1 Nitric Acid Solution Rinse with deionized water Cloudy and turbid samples may require filtering before running the test Report results as pg L soluble lead Use glass membrane type filter to avoid loss of lead by adsorption onto the filter paper If samples cannot be analyzed immediately see Sample Collection Preservation and Storage on page 5 Adjust the pH of preserved samples before analysis For more accurate results adjust the sample to pH 11 0 11 5 using a pH meter in Step 10 Omit the five additional drops of Sodium Hydroxide Standard Solution in Step 11 The DithiVer powder will not completely dissolve in the chloroform For further notes see DithiVer Solution Preparation Storage and Reagent Blank on page 5 Read the MSDS before testing Spilled reagent will affect test accuracy and is hazardous to skin and other materials Collect the following items Quantit
5. Reagent Powder Pillows to a 500 mL bottle of chloroform and invert several times until well mixed carrier powder may not dissolve Store dithizone solution in an amber glass bottle This solution is stable for 24 hours A reagent blank using deionized water should be carried out through the entire method to obtain the most accurate results Sample Collection Preservation and Storage Collect samples in an acid washed glass or plastic containers Adjust the pH to 2 or less with nitric acid about 2 mL per liter Store preserved samples up to six months at room temperature Adjust the pH to 2 5 with 5 0 N sodium hydroxide before analysis Correct the test result for volume additions Accuracy Check Lead_8033_Dithizone fm 1 Leave the unspiked sample in the sample cell compartment Verify that the units displayed are in ug L Press OPTIONS gt MORE Press STANDARD ADDITIONS A summary of the standard additions procedure will appear Press OK to accept the default values for standard concentration sample volume and spike volumes Press EDIT to change these values After values are accepted the unspiked sample reading will appear in top row See the user manual for more information Snap the neck off a Lead Voluette Ampule Standard 50 mg L Pb Use the TenSette Pipet do not use a glass pipet to add 0 1 mL 0 2 mL and 0 3 mL of standard respectively to three 250 mL samples and mix each thoroughly Analyze each standard addi
6. graduated 250 mL 1 each 508 46 Cylinder graduated mixing 50 mL 1 each 1896 41 Funnel separatory 500 mL 1 each 520 49 pH Meter sension 1 portable with electrode 1 each 51700 10 Sample Cell 1 inch square 25 mL with cap 2 2 pkg 26126 02 Spoon measuring 1 g 1 each 510 00 Support Ring 4 1 each 580 01 Support Ring Stand 5 x 8 base 1 each 563 00 Recommended Standards Description Unit Cat No Lead Standard Solution 100 mg L Pb 100 mL 12617 42 Lead Standard Solution 10 mL Voluette Ampules 50 mg L Pb 16 pkg 14262 10 Optional Reagents and Apparatus Description Unit Cat No Ampule Breaker Kit each 21968 00 Chloroform ACS 500 mL 14458 49 Filter Discs glass 47 mm 100 pkg 2530 00 Filter Holder glass for 47 mm filter each 2340 00 Flask Erlenmeyer 500 mL each 505 49 Flask filtering 500 mL each 546 49 Flask volumetric Class A 100 mL each 14574 42 Nitric Acid Solution 1 1 500 mL 2540 49 Nitric Acid ACS 500 mL 152 49 pH Paper pH 1 0 to 11 0 5 rolls pkg 391 33 Pipet serological 2 mL each 532 36 Pipet TenSette 0 1 to 1 0 mL each 19700 01 Pipet Tips for TenSette Pipet 19700 01 50 pkg 21856 96 Pipet volumetric 5 00 mL Class A each 14515 37 Pipet volumetric 10 00 mL Class A each 14515 38 Pipet Filler safety bulb each 14651 00 Sulfuric Acid 5 25 N 100 mL MDB 2449 32 Water deionized 4 liters 272 56 Lead Page 7 of 8 FOR TECHNICAL ASSISTANCE PRICE INFORMATION AND ORDERING HACH COMPANY In the U S A
7. n Standard 150 ug L Pb Program 95 Confidence Limits of Distribution 280 140 160 pg L Pb Sensitivity Portion of Curve AAbs AConcentration Entire Range 0 010 2 3 g L Summary of Method The dithizone method is designed for the determination of lead in water and wastewater The DithiVer Metals Reagent is a stable powder form of dithizone Lead ions in basic solution react with dithizone to form a pink to red lead dithizonate complex which is extracted with chloroform Test results are measured at 515 nm Consumables and Replacement Items Required Reagents Description Quantity Test Unit Cat No Lead Reagent Set 100 Tests 22431 00 Includes 1 14202 99 2 14458 17 1 12616 99 2 767 14 1 2450 53 2 2450 26 Buffer Powder Pillows citrate 1 100 pkg 14202 99 Chloroform ACS 30 mL 4L 14458 17 DithiVer Metals Reagent Powder Pillows 1 100 pkg 12616 99 Potassium Cyanide 0 1g 125g 767 14 Sodium Hydroxide Solution 5 0 N 5mL 1000 mL 2450 53 Sodium Hydroxide Standard Solution 5 0 N varies 59 mL DB 2450 26 Lead Page 6 of 8 Lead_8033_Dithizone fm Required Apparatus Lead 3 to 300 ug L Lead_8033_Dithizone fm Description Quantity Test Unit Cat No Clippers for opening powder pillows 1 each 968 00 Cotton Balls absorbent 1 100 pkg 2572 01 Cylinder graduated 5 mL 1 each 508 37 Cylinder graduated 50 mL 1 each 508 41 Cylinder
8. on with a second graduated cylinder and add to the separatory funnel Stopper and invert to mix Open stopcock to vent Close the stopcock 4 Transfer the sample into 500 mL separatory funnel 8 Add5mLof5 0N Sodium Hydroxide Standard Solution Lead Page 2 of 8 Lead_8033_Dithizone fm 9 Stopper Invert Open stopcock to vent Close the stopcock and shake the funnel once or twice and vent again Note Add a few drops of 5 25 N Sulfuric Acid Standard Solution if the solution turns orange on shaking The blue green color will reappear To avoid higher blanks repeat procedure on new sample and use less sodium hydroxide in step 8 HRS MIN SEC 13 Wait one minute for the layers to separate The bottom chloroform layer will be pink if lead is present Lead_8033_Dithizone fm 10 Continue adding 5 0 N Sodium Hydroxide Standard Solution dropwise and shaking the funnel after every few drops until the color of the solution being shaken changes from blue green to orange Large amounts of zinc cause the color transition at the end point to be indistinct a 14 Prepared Sample Insert a cotton plug the size of a pea into the delivery tube of the funnel and slowly drain the bottom chloroform layer into a dry 25 mL square sample cell Stopper The lead dithizone complex is stable for at least thirty minutes if the sample cell is kept tightly capped and out of direct sunlight 11 Add
9. tion sample as described above Accept the standard additions reading by pressing the soft key under READ each time Each addition should reflect approximately 100 recovery After completing the sequence press GRAPH to view 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 Lead Page 5 of 8 Lead 3 to 300 ug L Standard Solution Method 1 Prepare a 10 mg L lead standard solution by pipetting 10 00 mL of Lead Standard Solution 100 mg L into a 100 mL volumetric flask Add 0 2 mL of concentrated nitric acid using a TenSette Pipet to prevent the adsorption of lead onto the container walls Dilute to the mark with deionized water and mix thoroughly To make a 200 yg L standard pipet 5 00 mL of the 10 0 mg L standard into 245 mL of deionized water in the 500 mL separatory funnel in Step 4 of the Dithizone procedure Prepare these solutions daily Perform the lead procedure as described above To adjust the calibration curve using the reading obtained with the standard solution press OPTIONS gt MORE on the current program menu Press STANDARD ADJUST Press ON Press ADJUST to accept the displayed concentration If an alternate concentration is used press the number in the box to enter the actual concentration then press OK Press ADJUST Method Performance Precisio
10. y Citrate Buffer Powder Pillows 1 Chloroform 500 mL DithiVer Metals Reagent Powder Pillows 1 Lead Reagent Set 1 Potassium Cyanide 2g Sodium Hydroxide solution 5 0 N 5 mL Sodium Hydroxide Standard Solution 5 0 N varies Cotton Balls 1 Clippers 1 Cylinder 50 mL graduated mixing 1 Cylinder 5 mL graduated 1 Cylinder 50 mL graduated 1 Cylinder 250 mL graduated 1 Funnel 500 mL separatory 1 Sample Cells 1 inch square 25 mL 2 Spoon measuring 1 0 g 1 Support Ring 4 inch and Stand 5 x 8 inch base 1 Note Reorder information for consumables and replacement items is on page 6 Lead Lead_8033_Dithizone fm Page 1 of 8 Lead 3 to 300 ug L DANGER Cyanide is a deadly poison Use a fume hood Maintain cyanide solutions at pH 11 or greater to prevent formation of cyanide gas Stored Programs 280 Lead Dithizone Start 1 Select the test 5 Add the contents of one Buffer Powder Pillow for heavy metals citrate type Stopper the funnel and shake to dissolve 2 Insert the Multi cell Adapter with the 1 inch square cell holder facing the user a q 6 DithiVer Solution Preparation Add 50 mL of chloroform to a 50 mL mixing graduated cylinder Add the contents of one DithiVer Metals Reagent Powder Pillow Stopper the cylinder Invert several times to mix I 3 Fill a 250 mL graduated cylinder to the 250 mL mark with sample oy 7 Measure 30 mL of the prepared dithizone soluti
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