Determination of Pb and Cr in sunscreen samples by high-resolution continuum source graphite furnace atomic absorption spectrometry and direct analysis

A method has been developed for the determination of Cr and Pb in sunscreen samples by high-resolution continuum source graphite furnace atomic absorption spectrometry and direct analysis (HR-CS DS-GF AAS). Eleven commercial samples of different brands and different factors of sun protection sunscreen were analysed. For optimisation of the furnace temperature programme, pyrolysis and atomisation curves with M1 sunscreen sample were performed using a chemical modifier (0.05% Pd + 0.03% Mg + 0.05% Triton X-100) for Pb and without a modifier for Cr. The figures of merit obtained were: characteristic mass of 10 pg and 2.5 pg and limit of detection (LOD) of 3.0 mu g kg(-1) and 1.0 mu g kg(-1) for Pb and Cr, respectively, based on a sample mass of 4.5 mg. Relative standard deviation (RSD) values were lower than 9%, which are acceptable for direct analysis. For assessment of the accuracy of the method, sunscreen samples were digested. The results, obtained with direct determination of Pb and Cr in sunscreen samples and with acid digestion were statistically accordant, using the calibration with aqueous standards, showing that this calibration method is suitable for this application. The method developed for the analysis of sunscreen samples is accurate, simple, fast and suitable for routine application. (C) 2016 Elsevier B.V. All rights reserved.