Evaluation of pulsed electromembrane extraction for the analysis of diclofenac and mefenamic acid in biological fluids

Abstract

In the present study, electromembrane extraction (EME) and pulsed electromembrane extraction (PEME) coupled with high-performance liquid chromatography (HPLC) were compared for the extraction of two acidic drugs including diclofenac (DIC) and mefenamic acid (MEF). The effect of fundamental parameters on the extraction efficiency of both EME and PEME was investigated. Under optimized conditions, preconcentration factors in the range of 166 to 178 and 227 to 243 were obtained using EME and PEME, respectively. The limits of detection for DIC and MEF were obtained as 5.0 ng mL⁻¹ using EME and 2.5 ng mL⁻¹ by PEME. The dynamic linear ranges (DLRs) of both acidic drugs by EME were in the range of 20–250 ng mL⁻¹ (R² > 0.9970), whereas these ranges were 10–350 ng mL⁻¹ (R² > 0.9989) using PEME. The intra- and inter-assay precisions of the analysis were less than 5.36 and 6.64% by EME and 3.75 and 4.41 using PEME, respectively. The results showed that in comparison with EME, PEME is a more effective microextraction method, providing high extraction efficiencies in a short period of time. Finally, PEME was successfully used for the extraction of DIC and MEF from urine and plasma samples. The calibration curves showed good linearity for urine and plasma samples with the coefficients of determination higher than 0.9965. The limits of detection were obtained as 10 ng mL⁻¹ for DIC in both urine and plasma and 10 ng mL⁻¹ in urine and 15 ng mL⁻¹ in plasma for MEF by PEME.