Determination of Hexavalent Chromium Residues in Different Matrix Cosmetics by High Performance Liquid Chromatography-Inductively Coupled Plasma Mass Spectrometry

A method for the determination of Cr(Ⅵ) in cosmetics by high performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS) has been established. The samples were extracted using a 0.5 mol/L sodium hydroxide-0.28 mol/L anhydrous sodium bicarbonate-phosphate buffer solution through vortex ultrasonication followed by centrifugation. The mobile phase was 56 mmol/L nitric acid-80 mmol/L ammonia (pH=9.4, adjusted by ammonia). The samples were separated on a Hamilton PRP-X100 (250 mm×4.1 mm, 10 µm) anionic column and determined by ICP-MS. Under the optimized conditions, Cr(Ⅵ) had a good linear relationship in the range of 0 ~ 50 μg/L, and the correlation coefficient was r≥0.999. The limit of detection (LOD) of Cr(Ⅵ) was 0.0065 mg/kg, the limit of quantitation (LOQ) was 0.021 mg/kg, the spiked recoveries of samples were 85.0% ~ 97.0%, and the relative standard deviations (RSD) were 0.9%~6.9%. Cr(Ⅵ) was detected in cosmetic samples with different matrices with good reproducibility and sensitivity. The extraction of Cr(Ⅵ) from the samples was more complete with the alkaline extraction solution, and the extraction of Cr(Ⅵ) was more stable with the assistance of magnesium chloride, so the method is suitable for the determination of Cr(Ⅵ) in cosmetics with different matrices.