Voltammetric estimation of residual nitroxynil in food products using carbon paste electrode

A simple and sensitive voltammetric method was developed and validated for the recognition of the veterinary drug nitroxynil (NTX). The method is based on studying its voltammetric behavior at a carbon paste electrode. Square wave voltammetry (SWV) was successfully applied in this study. The anodic peak current obtained was a linear function of NTX concentration in Britton Robinson buffer of pH 3 over the range of 3.9 × 10(–6)–1.0 × 10(−4) M with lower detection and quantitation limits of 3.1 × 10(–7) and 9.4 × 10(–7) M, respectively. The proposed method was first applied to the assessment of the drug in commercial vials. The method was further used to monitor the residual amounts of the drug in bovine meat, kidney, fat, and milk samples. The results obtained were favourably compared with those given by reference method. The interference likely to be introduced by co-administered drugs was evaluated. The electrode reaction was elucidated, and electron transfer kinetics were studied.