Simultaneous determination of lead, arsenic, and mercury in cosmetics using a plastic based disposable electrochemical sensor

Inspection of heavy metals, such as lead (Pb), arsenic (As), and mercury (Hg), in cosmetic is routinely conducted because of their enhancement in skin treatment. This paper describes an electrochemical method for simultaneous determination of Pb, As, and Hg in cosmetics based on the cost-effective gold-sputtered plastic electrodes. The parameters for electrode fabrication and differential pulse stripping voltammetry (DPSV), including duration of sputtering, deposition potential and deposition time, were optimized. Cosmetic samples were treated via microwave digestion coupled with addition of Na2SO3 to convert all target metal elements to certain ions, namely, Pb(II), As(III) and Hg(II). Under optimized conditions, detection limits (S/N = 3) of 2 μg L−1, 5 μg L−1 and 0.5 μg L−1 could be obtained for Pb(II), As(III) and Hg(II), respectively. We also investigated mutual interferences among three target metal ions. The proposed approach was applied for simultaneous determination of three target metal ions in cosmetic certified reference materials and real cosmetic samples with satisfactory results. This approach may serve as an attractive alternative to conventional methods in routine analysis of heavy metal ions in cosmetics.