Selective Cosmetic Mercury Analysis Using a Silver Ink Screen‐Printed Electrode with Potassium Iodide Solution

A new method for selective determination of trace mercury has been demonstrated by linear scan voltammetry using silver ink screen printed electrode (AgSPE) in presence of potassium iodide (KI) dissolved 0.05 M H₂SO₄ solution. At AgSPE, iodide oxidation peak current signal found to be systematically decreased (inhibitory current anodic peak current signal, i ) with increase in the Hg concentrations, Hg]. This observation is further utilized for construction of new Hg electroanalytical assays in this work. On the AgSPE, Hg inhibitory detection potential found at 0 V vs. Ag/AgCl, which is 720 mV lower than that of unmodified SPE system. Under optimal experimental conditions, i signals were linearly increased against Hg] in the window of 500–4500 ppb (40 μM KI) with a correlation coefficient (r) of 0.9988. The limit of detection (LOD) and limit of quantification (LOQ) were 98 and 318 ppb, respectively. This approach was further utilized to analyze hidden Hg in the cosmetic samples. Real sample assays were consistent with that of result obtained from ICP‐OES, which confirm the applicability of the proposed method for practical applications.