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

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 mu g g(-1)- for Cl and 0.2 mu g 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 mu g g(-1)- and from 13 to 1328 mu g g(-1), respectively.

Automated summary

A new method for the direct analysis of Cl and S in flour was proposed, utilizing an elemental analyzer. Operational conditions were optimized and calibrated using standard solutions, resulting in accurate results with low detection limits. Various types of flour were analyzed, showing a wide range of concentrations for Cl and S.