Hach DR2400 - Page 463

Nitrite
Nitrite
Nitrite_UniCell_Low_DAZ_Eng_Ody.fm Page 3 of 4
Accuracy Check
Standard Solution Method
Prepare a 0.25-mg/L NO
2
–
–N standard solution by pipetting 1.00 mL of
250-mg/L NO
2
–
–N standard into a 1000-mL volumetric flask. Dilute to the mark
with deionized water. Stopper and invert to mix. Prepare this solution daily.
Perform the nitrite procedure as described.
Method Performance
Precision
Standard: 0.300 mg/L NO
2
–
–N
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
Nitrites react with primary aromatic amines in an acidic solution to form
diazonium salts. These salts combine with aromatic compounds that contain an
amino group or a hydroxyl group to form intensely colored azo dyes. Test results
are measured at 515 nm.
Required Reagents
Description Unit Cat. No.
Nitrite - (NO
2
–
–N), UniCell™ HCT 116
*
......................................................................... 23/pkg.............. HCT 116
Required Apparatus
Adapter, 16-mm Cell .......................................................................................................... each....................59457-00
Optional Apparatus
Flask, volumetric, 50-mL ................................................................................................... each....................14574-41
Flask, volumetric, 100-mL ................................................................................................. each....................14574-42
Flask, volumetric, 1000-mL ............................................................................................... each....................14574-53
Graduated cylinder, mixing, 100-mL............................................................................... each....................20886-42
Optional Standards
Nitrite Standard Solution, 250-mg/L .............................................................................. 500 mL...............23402-49
Program 95% Confidence Limits of Distribution
807 0.230–0.370 mg/L NO
2
–
–N
Program Portion of Curve ∆Abs ∆Concentration
807 Entire range 0.010 0.1 mg/L NO
2
–
–N
* Available in Europe only