Method 8038
Contents
1. Table 1 Interfering Substances and Levels continued Interfering Substance Interference Levels and Treatments Glycine various aliphatic and aromatic amines organic chloramines acetone aldehydes and alcohols May cause greenish or other off colors or turbidity Distill the sample if these compounds are present Sample Collection Storage and Preservation Collect samples in clean glass or plastic bottles If chlorine is present add one drop of 0 1 N Sodium Thiosulfate for each 0 3 mg L Cl in a 1 liter sample Preserve the sample by reducing the pH to 2 or less with sulfuric acid at least 2 mL Store at 4 C 39 F or less Preserved samples may be stored up to 28 days Warm samples to room temperature and neutralize with 5 N Sodium Hydroxide before analysis Correct the test result for volume additions Accuracy Check Standard Additions Method Sample Spike 1 2 After reading test results leave the sample cell unspiked sample in the instrument 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 the top row See the user manual for more information Snap the neck off a Nitrogen Ammonia Voluette Ampule Standard 50 mg L NH3 N2. Flask volumetric Class A 50 mL each 14574 41 Nitrogen Ammonia Standard Solution 1 mg L NH3 N 500 mL 1891 49 Nitrogen Ammonia Standard Solution 10 mL Voluette Ampule 50 mg L NH3 N 16 pkg 14791 10 Pipet TenSette 0 1 1 0 mL each 19700 01 Pipet Tips for TenSette Pipet 19700 01 50 pkg 21856 96 Pipet Tips for TenSette Pipet 19700 01 1000 pkg 21856 28 Pipet volumetric Class A 1 00 mL each 14515 35 Wastewater Effluent Inorganics for NH3 N NO3 N PO COD SO 4 TOC 500 mL 28332 49 Optional Reagents and Apparatus Description Cat No Distillation Apparatus General 22653 00 Heater and Support Apparatus 115 VAC 60 Hz 22744 00 Heater and Support Apparatus 230 VAC 50 Hz 22744 02 Mixing Cylinders 20886 40 Pour Thru Cell Kit LZV479 Sodium Thiosulfate 0 1 N 323 32 Sodium Hydroxide 5 N 2450 32 NitrogenAmm_8038_NES fm Nitrogen Ammonia Page 5 of 6 FOR TECHNICAL ASSISTANCE PRICE INFORMATION AND ORDERING HACH COMPANY In the U S A 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 1
3. If an alternate concentration is used press the number in the box to enter the actual concentration then press OK Press ADJUST Method Performance Precision Standard 1 00 mg L NH3 N Program 95 Confidence Limits of Distribution 380 0 99 1 01 mg L NH3 N Sensitivity Portion of Curve AAbs AConcentration Entire range 0 010 0 02 mg L NH3 N2 Distillation 1 Measure 250 mL of sample into a 250 mL graduated cylinder and pour into a 400 mL beaker Destroy chlorine if necessary by adding 2 drops of Sodium Arsenite Solution per mg L Clo 2 Add 25 mL of Borate Buffer Solution and mix Adjust the pH to about 9 5 with 1 N sodium hydroxide solution Use a pH meter 3 Set up the General Purpose Distillation Apparatus as shown in the Distillation Apparatus Manual Pour the solution into the distillation flask Add a stir bar 4 Use a graduated cylinder to measure 25 mL of deionized water into a 250 mL Erlenmeyer flask Add the contents of one Boric Acid Powder Pillow Mix thoroughly Set the flask under the still drip tube Elevate so the end of the tube is immersed in the solution 5 Turnon the heater power switch Set the stir control to 5 and the heat control to 10 Turn on the water and adjust to maintain a constant flow through the condenser 6 Turn off the heater after collecting 150 mL of distillate Immediately remove the collection flask to avoid sucking solution into the still Measu
4. Prepare three sample spikes Fill three mixing cylinders with 25 mL of sample Use the TenSette Pipet to add 0 1 mL 0 2 mL and 0 3 mL of the 50 mg L standard respectively to each sample and mix thoroughly Analyze each sample spike as described in the procedure above starting with the 0 1 mL sample spike Accept each standard additions reading by pressing READ 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 Standard Solutions Method 1 To check accuracy use a 1 0 mg L Nitrogen Ammonia Standard Solution Or prepare a 1 0 mg L ammonia nitrogen standard solution by pipetting 1 00 mL of Nitrogen Ammonia Voluette Ampule Standard 50 mg L into a 50 mL volumetric flask Dilute to the mark with deionized water Prepare this solution daily Perform the Nessler 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 See Optional Reagents and Apparatus on page 5 NitrogenAmm_8038_NES fm Nitrogen Ammonia Page 3 of 6 Nitrogen Ammonia 0 02 to 2 50 mg L NH3 N 3 Press ON Press ADJUST to accept the displayed concentration
5. cell holder with the fill line facing the user Press ZERO The display will show 0 00 mg L NH3 N 11 Wipe the prepared sample and insert it into the cell holder with the fill line facing the user Results are in mg L NH3 N Table 1 Interfering Substances and Levels Interfering Substance Interference Levels and Treatments Remove residual chlorine by adding 2 drops of sodium arsenite for each mg L chlorine Clo Chlorine from a 250 mL sample Sodium thiosulfate can be used instead of sodium arsenite See Sample Collection Storage and Preservation A solution containing a mixture of 500 mg L CaCO and 500 mg L Mg as CaCO does not Hardness interfere If the hardness concentration exceeds these concentrations add extra Mineral Stabilizer Iron Interferes at all levels by causing turbidity with Nessler Reagent May be analyzed by adding of 1 0 mL 27 drops of Mineral Stabilizer to the sample before analysis This complexes the high magnesium concentrations found in sea water but the Seawater sensitivity of the test is reduced by 30 percent due to the high chloride concentration For best results perform a calibration using standards spiked to the equivalent chloride concentration or distill the sample as described below Sulfide Interferes at all levels by causing turbidity with Nessler Reagent Nitrogen Ammonia Page 2 of 6 NitrogenAmm_8038_NES fm Nitrogen Ammonia 0 02 to 2 50 mg L NH3 N
6. Nitrogen Ammonia Method 8038 Nessler Method 0 02 to 2 50 mg L NH3 N Scope and Application For water wastewater and seawater distillation is required for wastewater and seawater USEPA accepted for wastewater analysis distillation required see Distillation on page 4 of this procedure 1 Adapted from Standard Methods for the Examination of Water and Wastewater 4500 NH3 B amp C 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 Subtract the reagent blank value from the final results or perform a reagent blank adjust See the user manual for more information Nessler Reagent contains mercuric iodide Both the sample and the blank will contain mercury D009 at a concentration regulated as a hazardous waste by the Federal RCRA Do not pour these solutions down the drain Refer to a current MSDS for safe disposal and handling instructions If using the Pour Thru Cell periodically clean the cells by pouring a few sodium thiosulfate pentahydrate crystals into the cell funnel Flush with enough deionized water to dissolve Rinse the cell thoroughly Collect the following items Quantity Ammonia Nitrogen Reagent set 1 Deionized Water 25 mL Graduated Mixing Cylinders 2 Sample Cells 1 inch square 10 mL 2 Serological Pipet 1 mL 2 Note Reorder information for consumables and replacement i
7. re the distillate to ensure 150 mL was collected total volume 175 mL 7 Adjust the pH of the distillate to about 7 with 1 N sodium hydroxide Use a pH meter 8 Pour the distillate into a 250 mL volumetric flask rinse the Erlenmeyer with deionized water Add the rinsings to the volumetric flask Dilute to the mark Stopper Mix thoroughly Analyze as described above Summary of Method The Mineral Stabilizer complexes hardness in the sample The Polyvinyl Alcohol Dispersing Agent aids the color formation in the reaction of Nessler Reagent with ammonium ions A yellow color is formed proportional to the ammonia concentration Test results are measured at 425 nm Nitrogen Ammonia Page 4 of 6 NitrogenAmm_8038_NES fm Nitrogen Ammonia 0 02 to 2 50 mg L NH3 N Consumables and Replacement Items Required Reagents Description Quantity Test Unit Cat No Ammonia Nitrogen Reagent Set includes 24582 00 Nessler Reagent 2mL 500 mL 21194 49 Mineral Stabilizer 6 drops 50 mL SCDB 23766 26 Polyvinyl Alcohol Dispersing Agent 6 drops 50 mL SCDB 23765 26 Water deionized 25 mL 4L 272 56 Required Apparatus Description Quantity Test Unit Cat No Cylinder graduated mixing 25 mL 2 each 20886 40 Pipet serological 1 mL 2 each 9190 02 Pipet Filler safety bulb 1 each 14651 00 Sample Cells 1 inch square 10 mL matched pair 2 2 pkg 24954 02 Recommended Standards and Apparatus Description Unit Cat No
8. tems is on page 5 Note Nessler Reagent is toxic and corrosive Pipet carefully using a pipet filler When dispensing reagent from a dropper bottle hold the bottle vertically Do not hold the bottle at an angle Note A yellow color will develop if ammonia is present The reagent will cause a faint yellow color in the blank Stored Programs 380 N Ammonia Ness Start 1 Select the test 2 Insert the Multi cell 3 Prepared Sample 4 Blank Preparation Gama en Adapter with the 1 inch Fill a 25 mL mixing Fill a 25 mL mixing square cell holder facing graduated cylinder to the graduated cylinder to the the user 25 mL mark with sample 25 mL mark with deionized water Nitrogen Ammonia NitrogenAmm_8038_NES fm Page 1 of 6 Nitrogen Ammonia 0 02 to 2 50 mg L NH3 N 5 Add three drops of Mineral Stabilizer to each cylinder Stopper and invert several times to mix au ane 10 mL 10 mL 9 Pour 10 mL of each solution into a square sample cell Interferences oe OK 01 00 8 Press TIMER gt OK EY 7 Pipet 1 0 mL of Nessler Reagent into each cylinder Stopper and invert several times to mix 6 Add three drops of Polyvinyl Alcohol Dispersing Agent to each cylinder Stopper and invert several times to mix A one minute reaction period will begin 10 When the timer expires insert the blank into the
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