Determination of widely used non-steroidal anti-inflammatory drugs in biological fluids using simultaneous derivatization and air-assisted liquid–liquid microextraction followed by gas chromatography–flame ionization detection

Abstract

A sensitive and reliable method for the extraction, preconcentration, and determination of non-steroidal acidic anti-inflammatory drugs (ibuprofen, naproxen, and diclofenac) from biological samples has been developed using simultaneous derivatization and air-assisted liquid–liquid microextraction followed by gas chromatography–flame ionization detection. In this method, a mixture of an extraction solvent (chloroform) and a derivatizing agent (butyl chloroformate) is added into a glass test tube containing an aqueous sample of the analytes and picoline (catalyst). The mixture is dispersed by repeatedly aspirating and dispensing via a syringe. By this action, derivatization and extraction of the selected analytes is performed simultaneously. Under the optimal conditions, enrichment factors and extraction recoveries were obtained in the ranges 364–412 and 72–82 %, respectively. The linear ranges were broad with correlation coefficients higher than 0.995. Limits of detection were obtained in the ranges 0.06–3.30 and 0.24–13 ng mL⁻¹ in urine and plasma samples, respectively. Limits of quantification were 0.21–9.2 ng mL⁻¹ in urine and 0.84–37 ng mL⁻¹ for plasma sample. Relative standard deviations were lower than 5.2 % for six repeated determinations at a concentration of 25 ng mL⁻¹ of each analyte. Finally, the developed method was successfully applied to determine the selected analytes in urine and plasma samples.