Evaluation of phenolic assays for the detection of nitrite

A series of generic nitrite assay systems based on the single step nitrosation of phenol derivatives are presented. The chemical reactivity offered by the C-nitroso compounds provides an opportunity to pursue a number of analytical strategies of which three spectroscopic (UV/Vis) and two electrochemical options (linear sweep voltammetry/differential pulse voltammetry) were evaluated. The capacity for multiple detection options from a single analyte species without significant sample manipulation is a major advantage with each assay system providing sub ppm detection limits with linear ranges up to milli-molar concentrations of nitrite. The influence of common interferents such as nitrate, ascorbate and paracetamol was investigated. The applicability of the assay procedures to the analysis of authentic biological samples (saliva and urine samples) was assessed with the analytical accuracy independently corroborated with a standard Griess protocol. In addition, a brief comparison with alternative nitrite detection strategies is also presented. (C) 1999 Elsevier Science B.V. All rights reserved.