Nitrite-nitrogen – LaMotte DC1600 Colorimeter User Manual

Page 61

NITRITE-NITROGEN

DIAZOTIZATION METHOD

CODE 3650

QUANTITY

CONTENTS

CODE

2 x 60 mL

*Mixed Acid Reagent

*V-6278-H

5 g

*Color Developing Reagent

*V-6281-C

Spoon, 0.1 g, plastic

0699

Dispenser Cap

0692

*WARNING: Reagents marked with a * are considered hazardous substances. Material Safety Data Sheets (MSDS) are supplied for

these reagents. For your safety, read label and accompanying MSDS before using.

Nitrite represents an intermediate state in the nitrogen cycle, usually resulting from the bacterial decomposition of

compounds containing organic nitrogen. Under aerobic conditions bacteria oxidize ammonia to nitrites; and under

anaerobic conditions, bacteria reduce nitrates to nitrites. Nitrites are often used as preservatives when added to certain

foods.
The nitrite concentration of drinking water rarely exceeds 0.1 ppm (mg/L).

APPLICATION:

This method is applicable for the determination of nitrite in drinking, surface and saline

waters; domestic and industrial wastes.

RANGE:

0 – 0.7 ppm Nitrite-Nitrogen

METHOD:

Nitrite is determined by diazotization of sulfanilamide and nitrite followed by coupling with

N-(1 naphthyl)-ethylenediamine dihydrochloride to form a highly colored azo dye which is

measured colorimetrically.

SAMPLE HANDLING

& PRESERVATION:

Samples should be analyzed as soon as possible. They may be stored for 24 to 48 hours at 4°C.

INTERFERENCES:

Ion concentrations present at less than 1000 times the nitrite concentration do not interfere;

however, the presence of strong oxidants or reductants may readily affect nitrite

concentrations. High alkalinity (above 600 mg/L) will give low results due to a shift in pH.