Comparison of Chromatographic and Electrochemical Methods for Detecting and Quantifying Sunscreen Agents and Their Degradation Products in Water Matrices

Comparing electroanalysis and chromatography, this study highlights that electroanalysis, specifically using a glassy carbon sensor (GCS), is the most appropriate choice for quantifying recalcitrant organic compounds. Octocrylene (OC), an organic compound commonly found in sunscreens, is of particular concern in swimming pool water monitoring, as its presence above legal limits poses health risks. OC quantification was performed using both high performance liquid chromatography (HPLC) and electroanalysis in sunscreen formulations and water matrices. The limits of detection (LODs) and quantification (LOQ) for OC were approximately 0.11 ± 0.01 mg L−1 and 0.86 ± 0.04 mg L−1 by electroanalysis, and 0.35 ± 0.02 mg L−1 and 2.86 ± 0.12 mg L−1 by HPLC. Electroanalysis successfully quantified OC in real sunscreen samples, and the results were comparable to those obtained by HPLC. The matrices tested—swimming pool water and distilled water (containing 0.002 M Cl−) contaminated with 0.4 ± 0.2 g L−1 of sunscreen (based on a maximum concentration in sunscreen and cosmetic formulations of 10%)—showed OC concentrations below 10% in the formulation, with no significant differences observed between the two techniques. GCS was further utilized to monitor OC degradation via anodic oxidation at current densities of 5 and 10 mA cm−2, using a boron-doped diamond (BDD) anode. The combined approach demonstrated high efficacy in both detecting and eliminating OC from various water matrices, making it a reliable and efficient alternative for environmental and water quality monitoring.