Hach DR2400 - Page 469

Nitrogen, Ammonia
Nitrogen, Ammonia
NitrogenAmm_None_Other_NES_Eng_Ody.fm Page 5 of 6
5. Turn on 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. Measure 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.
Required Reagents
Quantity Required
Description Per Test Unit Cat. No.
Ammonia Nitrogen Reagent Set....................................................................................................................24582-00
Includes:
Nessler Reagent..................................................................................2 mL ................ 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 .............. 4 liters....................272-56
Required Apparatus
Cylinder, graduated, mixing, 25-mL......................................................2 ....................... each....................21190-40
Pipet, serological, 1-mL............................................................................2 ....................... each......................9190-02
Pipet Filler, safety bulb ............................................................................1 ....................... each....................14651-00
Sample Cells, 10-mL, w/cap...................................................................2 ....................... 6/pkg.................24276-06
Required Standards
Nitrogen, Ammonia Standard Solution, 1-mg/L NH
3
–N............................................ 500 mL.................1891-49
Nitrogen, Ammonia Standard Sol., 10-mL Voluette
®
Ampule, 50-mg/L NH
3
–N ... 16/pkg...............14791-10
Distillation Reagents
Borate Buffer Solution........................................................................................................ 1000 mL.............14709-53
Boric Acid Powder Pillows ............................................................................................... 100/pkg.............14817-99
Sodium Arsenite Solution, 5.0-g/L.................................................................................. 100 mL MDB.......1047-32
Sodium Hydroxide Standard Solution, 1.0 N................................................................. 100 mL MDB.......1045-32