Flow-injection Analysis Technique Used to Electrochemically Measure Nitrite through a Gold Working Electrode Modified with 1-2 Diaminobenzene (DAB)

Abstract

In this paper, it is presented nitrite analysis, electrochemically measured, using a Flow-injection Analysis (FIA) system. The importance of determining nitrite from water, food and blood is based on its toxicity for human health, even at low concentrations (<4mM). The presented electrochemical planar sensor uses silk-screen technology and has a working electrode covered with 1-2 Diaminobenzene (DAB) that allowed good selectivity, reproductively, stability and sensitivity at 0.75 VAg/AgCl Nafion® 117, 0.5 VAg/AgCl Nafion® 117 and 0.3 VAg/AgCl Nafion® 117. It was noteworthy that nitrite response adds to the response of the studied interfering elements (paracetamol, ascorbic acid and uric acid) and it is predominant for concentrations lower than 175 μmol L-1. Finally, the nitrite sensitivity was 11.2 mA mol-1 L mm-2 using the working electrode recovered with DAB at 0.5 VAg/AgCl Nafion®117.