Flow-Injection Analysis Method for the Determination of Nitrite and Nitrate in Natural Water Samples Using a Chemiluminescence NOx Monitor

• Published in: Analytical Sciences Vol. 19; no. 5; pp. 695 - 699
• Main Authors: KANDA, Yukio, TAIRA, Masafumi
• Format: Journal Article
• Language: English
• Published: Tokyo The Japan Society for Analytical Chemistry 01.05.2003; Japan Society for Analytical Chemistry; Japan Science and Technology Agency
• Subjects: Analytical chemistry; Applied sciences; Chemistry; Exact sciences and technology; Natural water pollution; Pollution; Rainwaters, run off water and others; Spectrometric and optical methods; Water treatment and pollution; Trace analysis; Chemical analysis; Nitrites; Chemiluminescence; Nitrates; Environmental control; Chemical pollution; Multicomponent analysis; Inorganic anion; Rain water; Luminescence spectrometry; Water pollution; Hydrazine; Quantitative analysis; Flow injection
• ISSN: 0910-6340; 1348-2246
• DOI: 10.2116/analsci.19.695

A flow-injection analysis method for the determination of nitrite and nitrate in natural water samples has been developed that consists of two systems based on their reduction to NO with hydrazine and/or ascorbic acid, followed by chemiluminescence detection. The procedure of sweeping the generated NO into an NOx monitor, by means of a gas-liquid separating coil consisting of microporous polytetrafluoroethylene (PTFE) tubing, offers practical advantages. The adjustment of the carrier gas-flow rates could yield the same calibration graphs for the two measurement systems, and the accumulation sweeping mode provides a higher sensitivity. Chemiluminescence detection allows a wide linear calibration range of 5 × 10-8 to 5 × 10-5 M. The detection limits for nitrate and nitrite, defined as three-times the standard deviation of measurement blanks, are 2 × 10-8 M and 1 × 10-8 M, respectively, and the average precision was 3.2% at ambient natural concentration levels. Recovery tests were between 94% and 106% for a variety of natural water samples. The method is relatively free from interferences from the substances normally found in natural water, and only ferric ion has an effect for the nitrite determination.