Extractive spectrophotometric determination of trace amounts of nitrogen dioxide, nitrite, and nitrate

Abstract

Abstract.A sensitive extractive spectrophotometric method for the determination of nitrogen dioxide in air and nitrite and nitrate in water, soil and blood serum is described. Nitrogen dioxide in air is fixed as nitrite in a suitable trapping solution. The method is based on the diazo coupling reaction between pnitroaniline and N-(1-naphthyl)ethylenediamine dihydrochloride [NEDA]. The azo dye formed under aqueous conditions is extracted with isobutyl methyl ketone [IBMK]. The system obeys Beer's law over the range 0-3 Ixg of nitrite at 545 nm and the colour is stable for 3 h. The molar absorptivity of the colour system is 5.7 x 10 4 L mol-lcm-1. The relative standard deviation is 1.3% for ten determinations at 2 gg of nitrite. Nitrate is determined as nitrite after reduction on a cadmium column. Negative interferences from SO2, HzS , Cu 2 + and Cr a § and positive interference from Fe 2 § and Fe 3 § can be simply masked.

Simultaneous Spectrophotometric Determination of Nitrate and Nitrite in Water and Some Vegetable Samples by Column Preconcentration

“…From the calibration curve, determine the nitrite content in some vegetable samples and calculate the nitrite content. The results given in Table 4 agree reasonably with results from an alternative method (16). The alternative procedure is as follows: Transfer an aliquot (up to 10 ml) of sample solution containing not more than 3 mg of nitrite into a 30-ml beaker and then to it add 1.0 ml of 0.05% p-nitroaniline solution and 4.0 ml of water.…”

Determination of nitrogen dioxide, sulfur dioxide, ozone, and ammonia in ambient air using the passive sampling method associated with ion chromatographic and potentiometric analyses

“…A poorly sensitive spectrophotometric method for determining NO 2 in air based on converting NO 2 into nitrite ions which was subsequently coupled with azodyes was reported (Pandurangappa and Balasubranian 1996 ). Chemiluminescence sensitive methods based on catalytic reduction of NO 2 to NO which was subsequently reacted with ozone or luminal were also reported (Robinson et al 1999 ; Mikuska and Vecera 2000 ).…”

Diaminobenzene as a Novel Reagent for Nitrite Assay in Environmental Samples: Evidence for Its Mechanistic Aspects

“…However, large amounts of this species may be toxic and cause eutrophication (Moore and Moore 1976;MAFF 1992). The toxicity of nitrite is primarily due to the result of its reaction with secondary or tertiary amines present in human body to form nitrosamines, which are known to be carcinogenic, teratogenic, and mutagenic (Henery and Heinke 1996;Masuda et al 2000;Pandurangappa and Balasubramanian 1996;Wu and Ruzicka 2001). Nitrate was reduced to nitrite by a copperized cadmium reductor column, and the nitrite and nitrate content can therefore be determined by measuring the difference between the responses with and without reduction (APHA 1995).…”