A solid sampling approach for direct determination of Cl and S in flour by an elemental analyzer

Abstract

Direct analysis of flour was proposed for the determination of Cl and S by an elemental analyzer for the first time. The main operational conditions of the direct solid sampling elemental analysis (DSS-EA) were optimized and calibrated by standard solutions, rather than by certified reference material (CRM). Accuracy was evaluated by the analysis of CRM of rice flour and by comparison with analyte determination by independent techniques, i.e., ion chromatography and inductively coupled plasma optical emission spectrometry; both were carried out after microwave-induced combustion. Sample mass from 0.5 to 260 mg was used and limits of quantification of 1.2 µg g−1 for Cl and 0.2 µg g−1 for S were achieved. Wheat, whole wheat, potato and corn flour were analyzed by DSS-EA. Concentrations of Cl and S ranged from 4.8 to 685 µg g−1 and from 13 to 1328 µg g−1, respectively.