Quantitative assessment of phosphate food additive in frozen and chilled chicken using spectrophotometric approach combined with graphitic digestion

Abstract

A new method based on spectrophotometry combined with graphitic digestion was developed for quantitative assessment of phosphate in frozen and chilled chicken meat. Digestion reagents comprising HNO₃ (conc.) & H₂SO₄ (conc.) and HNO₃ (5 M) & H₂SO₄ (conc.) were found to have optimal composition, affording similar recovery values of 100% and 99%, respectively, with excellent linearity (R² > 0.999) and good limit of detection (LOD = 0.032 mg/L) and limit of quantification (LOQ = 0.10 mg/L), whereas other reagents offered lower recoveries (0-1.73%). Phosphate was found in concentrations of 3.38-5.90 g/kg and 3.96-26.94 g/kg in frozen and chilled chicken, respectively. Chilled chicken contained higher amounts of phosphate (>20 g/kg) than recommended by the European Commission (EC, 5 g/kg), either alone or in a mixture of processed meat products. This method is simple, cost-effective, and can be used as an alternative for analyzing phosphate in various samples comprising a similar matrix.

Keywords: Chicken; Colorimetric; Graphitic digestion; Nitric acid; Phosphate; Spectrophotometer; Sulfuric acid.