Comparison of the analytical capabilities of an amperometric and an optical sensor for the determination of nitrate in river and well water

✍ Scribed by Margaret A. Stanley; Joe Maxwell; Mairead Forrestal; Andrew P. Doherty; Brian D. MacCraith; Dermot Diamond; Johannes G. Vos

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 992 KB
• Volume: 299
• Category: Article
• ISSN: 0003-2670
• DOI: 10.1016/0003-2670(94)00328-9

✦ Synopsis

The analysis of nitrate in water has been studied using novel amperometric and optical sensors. A flow-injection analysis system with amperometric detection has been developed in which nitrate is determined as nitrite after reduction in a cadmium column. The working electrode is glassy carbon modified with a crosslinked redox polymer. The linear range is 0.1 to 190 mg/ 1 NC&-N (r> 0.999) and the limit of detection (LOD) is 50 pg/l N03-N. A fibre optic sensor based on a dual wavelength absorption approach has also been developed. A signal at 210 nm where nitrate absorbs was referenced against a signal at 275 nm where nitrate does not absorb. Its linear range is from 0.4 to 30 mg/l N03-N and its LOD is 400 pg/l N03-N. These diverse methods have been applied to the analysis of the same river water samples and good correlations have been observed between the two measurement techniques and a standard ion chromatography method.