A Simple Approach Based on Extraction Induced by Emulsion Breaking for Determination of Ca, Cu, Fe, Mg, Mn and Zn in Multivitamin and Mineral Supplements by Flame Atomic Absorption Spectrometry

A method based on extraction induced by emulsion breaking was developed for the determination of Ca, Cu, Fe, Mg, Mn, and Zn in oil-based multivitamin and mineral dietary supplements by flame atomic absorption spectrometry. Under optimized conditions, 0.1 g of sample was emulsified with 4 mL of extractant solution containing 2.5% (w/v) Triton X-100 and 10% (v/v) HNO3. Emulsion breaking was achieved by heating at 90 °C for 10 min and centrifugation at 4000 rpm for 10 min. Limits of detection were 1.0, 1.0, 2.4, 0.022, 1.1, and 0.39 mg kg−1 for Ca, Cu, Fe, Mg, Mn, and Zn, respectively. The relative standard deviation (n = 3) was below 15% for all analytes. Measured concentrations were generally consistent with labeled values, with minor deviations observed in a few samples for Cu (77–79%), Fe (78–79%), and Mn (72%). Results were also compared with those obtained by inductively coupled plasma optical emission spectrometry after acid digestion, with extraction yields ranging from 82 to 109% for the tested elements.