A High‐Throughput Analytical Approach Using Polyaniline Doped With Oxalic Acid in Thin Film Solid‐Phase Microextraction for the Determination of Personal Care Products in Recreational Waters

ABSTRACT In this study, a high‐throughput analytical methodology was developed based on the thin film solid‐phase microextraction (TF‐SPME) technique, employing polyaniline (PAni) as the extractor phase for the determination of personal care products in recreational water samples. The compounds investigated included three parabens, methylparaben (MP), ethylparaben (EP), butylparaben (BP), the UV filter and benzophenone (BZP), with detection performed by high‐performance liquid chromatography with a diode‐array detector (HPLC‐DAD). Experimental conditions were optimized using univariate and multivariate approaches, evaluating the effects of the extractor phase, desorption solvent and time, sample pH, extraction time, and NaCl concentration. Optimal extraction conditions involved the use of PAni doped with oxalic acid, desorption in a mixture of ACN:MeOH (50:50) for 30 min, an extraction time of 150 min, sample pH adjusted to 7, and 20% NaCl. Calibration curves were performed in ultrapure water with determination coefficients greater than 0.9973. The limits of detection (LODs) and quantification (LOQs) were 1.5 and 5 µg L −1 , respectively, for all analytes. Intraday precision ranged from 2% to 19%, while inter‐day precision varied between 10% and 22%. Method accuracy was assessed through relative recovery experiments in a water sample from a swimming pool, with recoveries ranging from 74% to 109%. The developed method was applied to six recreational water samples. In three of them, the analyte concentrations were above the LOQ, while in the others, the analytes were not found or their concentrations were below the LOD.