Electrochemically enhanced solid-phase microextraction of amphetamines using loose multilayer...

A novel loose-multilayer polydimethylsiloxane/reduced graphene oxide composite (lmPDMS/rGO) was synthesized and immobilized onto a stainless steel wire to fabricate a solid-phase microextraction (SPME) fiber. The fiber exhibited a uniform multilayer structure, high thermal stability, mechanical robustness, and excellent electrical conductivity. It also demonstrated outstanding durability, remaining effective for up to 150 uses. Moreover, the fiber showed remarkable extraction efficiency for amphetamine-type stimulants (ATSs) in urine samples under an applied electric field. Analyte separation and quantification were performed using gas chromatography with a nitrogen phosphorus detector. Key extraction parameters (applied voltage, extraction time, stirring speed, and pH) were systematically optimized. Under the optimized conditions, calibration curves (5-500 ng L^-1) showed coefficients of determination >0.990, with relative recoveries of 82 %-105 %. Limits of detection (S/N = 3) and quantification (S/N = 10) ranged from 0.5 to 2.7 ng L^-1 and 1.8-9.1 ng L^-1, respectively. Intra- and inter-fiber RSDs were 3.9 %-6.2 % and 4.2 %-10.7 %, respectively. This study offers a promising strategy for designing functional PDMS-based composites with well-defined structure-performance relationships for enhanced SPME applications.