Electrochemical determination of 8-hydroxyquinoline in a cosmetic product on a glassy carbon electrode modified with 1-amino-2-naphthol-4-sulphonic acid

A new voltammetric method was developed for the simple, rapid and inexpensive determination of 8-hydroxyquinoline (8HQ) on a modified electrode obtained by the electrodeposition of 1-amino-2-naphthol-4-sulfonic acid (ANSA) on the surface of a glassy carbon (GC) electrode. The electrode interfacial properties were investigated by electrochemical impedance spectroscopy (EIS). The electrochemical response of the ANSA-GC electrode toward 8-hydroxyquinoline was investigated by the use of square wave voltammetry. The ANSA-GC modified electrode showed two linear plots with 8-hydroxyquinoline concentrations from 5 × 10−7 to 1.4 × 10−5 mol dm−3 (R2 of 0.9984) and from 1.4 × 10−5 to 4.25 × 10−4 mol dm−3 with a correlation coefficient R2 equal to 0.9967. The limit of detection was 1.6 × 10−7 mol dm−3. The ANSA-GC modified electrode also showed excellent stability and reproducibility for up to two weeks. The analytical application of the ANSA-GC modified electrode was investigated for the determination of 8-hydroxyquinoline in a blush cosmetic product. The results in good agreement to those obtained by spectrophotometry as a standard method.