Determination of Sulfite in Hair Waving Products Using Oxygen‐Incorporated Gold‐Modified Screen‐Printed Electrodes

An electrodeposition oxygen-incorporated gold-modified screen-printed carbon electrode (AuOSPE) was fabricated to determine the sulfite content in hair waving products. The AuOSPE showed an electrocatalytic current for sulfite at +0.4 V (vs. Ag/AgCl). Compared with a gold screen-printed electrode (AuSPE), the AuOSPE showed a higher electrocatalytic current. The increase in the electrocatalytic current was ascribed to the increase of the oxygen incorporated with gold atom on AuOSPE. The AuOSPE coupled with a flow injection analysis (FIA) system showed excellent oxidation current for sulfite in a 0.1 mol L−1 phosphate buffer solution (PBS), pH 6.0. The linear working range for determining the sulfite content was 0.05 to 1200 mg L−1 (0.625 µmol L−1 to 15.00 mmol L−1) with a calculated detection limit of 0.03 mg L−1 (0.375 µmol L−1) (DL, S/N=3). Relative standard deviations (RSD) of 3.03 %, 2.30 % and 4.26 % were calculated for consecutive injections (n=12) of 20, 300 and 900 mg L−1 sulfite, respectively. The amount of sulfite in two hair waving products was determined by the proposed method and a standard iodometric method. The recoveries ranged from 96.18 % to 105.61 %. The AuOSPE showed high sensitivity, selectivity, stability and reproducibility for sulfite.