New sol–gel hybrid material in solid phase extraction combined with liquid chromatography for the determination of non-steroidal anti-inflammatory drugs in water samples

Abstract

A new sol–gel hybrid methyltrimethoxysilane–mercaptopropyltrimethoxysilane (MTMOS–MPTMS) was synthesized, characterized and applied as sorbent for solid phase extraction (SPE) of selected non-steroidal anti-inflammatory drugs (NSAIDs) as target analytes. Analysis was performed using high performance liquid chromatography with UV detection at 234 nm. Under the optimum extraction conditions (100 mg sorbent, 20 mL sample loading volume and 7 mL acetonitrile as desorption eluent), the method using the sol–gel organic–inorganic hybrid MTMOS–MPTMS as SPE sorbent showed good linearity in the range of 1–550 μg L−1, good repeatability (RSD 1.4–6.0 %, n = 3), low limits of detection at S/N = 3 (0.10–0.29 μg L−1) and limit of quantification (0.33–0.89 μg L−1, S/N = 10). The developed MTMOS–MPTMS SPE method was successfully applied to real sample analysis of the selected NSAIDs from several water samples. In-house MTMOS–MPTMS sol–gel hybrid material was able to extract the selected NSAIDs (diclofenac sodium, ketoprofen, mefenamic acid) in water samples comparable to commercial cyano sorbent. Excellent relative recoveries (RR) and RSDs of the NSAIDs were obtained from the various water samples (RR: 85.8–104.2 %, RSDs 1.2–6.0 %, n = 3) using the MTMOS–MPTMS SPE sorbent. The sol–gel hybrid MTMOS–MPTMS SPE sorbent demonstrates promising potential as an alternative inexpensive extraction sorbent for NSAIDs from water samples and with higher selectivity.