Investigation of the performance of sol-gel methyltrimethoxysilane coated cotton: Miniaturized extraction of non-steroidal anti-inflammatory drugs

• Utilization of sol-gel MTMS coated cotton for urine sample preparation • Absolute extraction recoveries for NSAIDs ranged between 72 and 82% • Parallel sample handling of multiple samples in 8 min • Good practicality, analytical performance, innovation, and greenness In this work, sol-gel methyltrimethoxysilane (MTMS) coated cotton was used for the first time for the ultrasound-assisted extraction of four selected NSAIDs (i.e., ketoprofen, fenoprofen, flurbiprofen, and ibuprofen) from human urine samples prior to their separation and determination by high-performance liquid chromatography coupled to diode array detection. The extraction of the analytes was conducted in an ultrasonic bath, while for the elution step, the sol-gel MTMS coated cotton segment was firmly packed at the bottom of the syringe, to obtain a stable and permeable extraction platform during eluent aspiration and dispensation. The parameters that were expected to affect the performance of the sample preparation step were thoroughly optimized, the new material was extensively characterized, and the method was validated. The obtained absolute extraction recoveries were 72-82%, showing high sorbent affinity towards the target analytes. The limits of detection were 0.015 μg mL −1 for all analytes. Moreover, good method precision and trueness were demonstrated. The relative standard deviations were less than 11.1% for intra-day and less than 13.9% for inter-day study. The relative recoveries were between 86 and 114% in all cases. The practicality, analytical performance, innovation, and greenness of the new method were examined using appropriate metrics tools. Finally, the method was employed for the analysis of real samples obtained from a volunteer under regular ibuprofen treatment.