LaMotte SMART 2 Electronic Soil Lab - Manual (Page 71)

NITRITE-NITROGEN
DIAZOTIZATION METHOD CODE 3650-SC
QUANTITY CONTENTS CODE
2 x 60 mL *Mixed Acid Reagent *V-6278-H
5 g *Color Developing Reagent *V-6281-C
1 Spoon, 0.1g 0699
1 Dispenser cap 0692
*WARNING: Reagents marked with a * are considered to be potential health hazards. To view
or print a Material Safety Data Sheet (MSDS) for these reagents see MSDS CD or
www.lamotte.com. To obtain a printed copy, contact LaMotte by e-mail, phone or fax.
Nitrites are formed as an intermediate step in the production of nitrate. Soils
that are well drained and aerated contain only small amounts of nitrite
nitrogen. Excessive nitrites, which are toxic to plants, may result from soil
conditions unfavorable to the formation of nitrate, such as inadequate aeration.
High nitrite readings may also be encountered in soils with large amounts of
nitrates, where a portion of the nitrate nitrogen decomposes to form nitrites.
RANGE: 0.00-40.00 lb/acre Nitrate-Nitrogen
METHOD: The diazonium compound formed by diazotization of
sulfanilamide by nitrite in water under acid
conditions is coupled with
N-(1-naphthyl)-ethylenediamine to produce a
reddish-purple color which is read colorimetrically.
INTERFERENCES: There are few known interferences of substances at
concentrations less than 1000 times that of nitrite;
however, the presence of strong oxidants or
reductants may readily affect the nitrite
concentrations. High alkalinity (above 600 mg/L)
will give low results due to a shift in pH.
SMART2 SOIL MANUAL 1.07 71