Analytical Methodology for Determination of Nonsteroidal Anti‐Inflammatory Drugs in Water Samples Using Polyaniline‐Silica Doped With Hydrochloric Acid as a Novel Extractor Phase in Thin Film Solid Phase Microextraction

ABSTRACT A novel analytical methodology was developed in this study for the determination of four nonsteroidal anti‐inflammatory drugs, including aspirin, naproxen, ibuprofen, and mefenamic acid in water samples using high‐performance liquid chromatography‐diode array detection. The thin film solid‐phase microextraction technique was employed, coupled with a 96‐well plate sampling system, and polyaniline‐silica doped with hydrochloric acid was used as the extractor phase. The optimized conditions were obtained through univariate and multivariate approaches, and the optimum extraction conditions were 1.5 mL of sample, pH 3, without salt addition, and 300 μL of acetonitrile. Calibration curves were obtained using spiked ultrapure water; the linear ranges were from 15 to 500 μg L −1 , and the determination coefficients were higher than 0.9957. Detection and quantification limits were 4.55 and 15 μg L −1 , respectively. The relative recoveries varied from 81% to 117% in a river water sample at three different concentration levels for each analyte. The intraday ( n  = 3) and interday ( n  = 9) precision values obtained were ≤ 8% and ≤ 15%, respectively.