Mercury Extraction from Multivitamin Mixtures Followed by Determination Using FI-CV-ICP-MS

Abstract

This study deals with a method for Hg determination in multivitamin supplements. Mercury was extracted with L-cysteine prior to its determination using flow injection-cold vapor generationinductively coupled plasma-mass spectrometry. A miniaturized flow injection system was employed for Hg vapor generation and its introduction in the plasma whereas 1% (v v-1) HCl and 0.005% (m v-1) NaBH4 were used for that purpose. Mercury extraction was carried out using 6 mL of 1% m v-1 L-cysteine and 50 mg of sample. Accuracy was proved by comparing the Hg concentration found using L-cysteine with the Hg concentration found in the sample decomposed using microwave-assisted digestion, and analysis of certified soil. The limits of detection and quantification of the proposed method were 2 and 6 ng g-1 of Hg, respectively. The relative standard deviation was < 10% (n = 5). Five samples of multivitamin supplements were analyzed and, in any sample, the tolerable amount of Hg (4.0 µg kg-1 body weight) recommended by the World Health Organization was exceeded. The proposed method for Hg determination meets the current legislation and is feasible for Hg monitoring in multivitamin supplements.