Hach DR2400 - Page 455

Nitrite
Nitrite
Nitrite_PP_High_FES_Eng_Ody.fm Page 3 of 4
Accuracy Check
Standard Solution Method
Preparing nitrite standards is difficult. A standard should be prepared by a
trained chemist. Hach recommends using the standard preparation instructions
in Standard Methods for the Examination of Water and Wastewater. Prepare a
200-mg/L standard using Sodium Nitrite, ACS (Cat. No. 2452-01).
Method Performance
Precision
Standard: 200 mg/L NO
2
–
See Section 3.4.3 Precision on page 44 for more information, or if the standard
concentration did not fall within the specified range.
Sensitivity
See Section 3.4.5 Sensitivity on page 44 for more information.
Summary of Method
The method uses ferrous sulfate in an acidic medium to reduce nitrite to nitrous
oxide. Ferrous ions combine with the nitrous oxide to form a greenish-brown
complex in direct proportion to the nitrite present. Test results are measured at
585 nm.
Required Reagents
Quantity Required
Description Per Test Unit Cat. No.
NitriVer
®
2 Nitrite Reagent Powder Pillows ........................................1 pillow........... 100/pkg.............21075-69
Water, Deionized................................................................................................................. 4 liters ....................272-56
Required Apparatus
Sample Cells, 10-mL, w/cap...................................................................2 ....................... 6/pkg.................24276-06
Program 95% Confidence Limits of Distribution
373 193–207 mg/L NO
2
–
Portion of Curve ∆Abs ∆Concentration
Entire range 0.010 1.6 mg/L NO
2
–