Accurate concentration determination of anions nitrate, nitrite and chloride in minced meat using a voltammetric electronic tongue
Abstract A method for predicting levels of chloride, nitrite and nitrate in minced meat by using an electronic tongue based on pulse voltammetry is proposed here. The electronic tongue consists of a set of noble (Au, Pt, Rh, Ir, Ag) and non-noble (Ni, Co, Cu) electrodes that were housed inside a stainless steel cylinder used at the same time as both the body of the electronic tongue system and the counter/reference electrode. An electrochemical study of the response of the anions Cl − , NO 3 − and NO 2 − using the different noble and non-noble electrodes was carried out in water in order to design a set of pulses for the electronic tongue. The determination of the concentration of chloride, nitrate and nitrite with the voltammetric tongue was carried out on both saline solutions (brines) and minced meat. The addition of the salts was performed following an experimental design in which a system of three compounds/three levels was established. Multivariate analysis including cross validation and partial least square (PLS) techniques were applied for data management and prediction models building. A very good prediction of the concentration of the anions chloride, nitrate and nitrite was achieved in brines. In minced meat, PLS models showed reduction in the prediction capabilities caused by a matrix effect, nevertheless the system still shows good accuracy and precision in the determination of concentration levels of these anions.