Sensitive determination of amphetamine-type stimulants in human hair by electro-enhanced solid-phase microextraction coupled to gas chromatography with nitrogen-phosphorus detector

In the field of forensic sciences, the analysis of amphetamine-type stimulants in hair samples has become a fundamental tool for assessing long-term substance use. The persistent nature of amphetamine-type stimulants in hair provides a unique chronological record of drug intake, offering valuable insights for legal and clinical applications. Developing a simple, sensitive, and reliable method for the determination of these drugs in hair samples remains an important issue in forensic analysis. In this study, polydimethylsiloxane modified stainless steel fiber was firstly fabricated. By taking advantage of the affinity of the polydimethylsiloxane coating toward amphetamine-type stimulants and the excellent conductivity of stainless steel wire, an electro-enhanced solid-phase microextraction coupled with gas chromatography equipped with a nitrogen-phosphorus detector method was established to sensitively determine four common amphetamine-type stimulants in hair samples. The experimental results showed a linear range from 0.1 to 50 µg L⁻¹. The limits of detection and qualification respectively varied from 0.012 to 0.039 and 0.05 to 0.13 µg L⁻¹ (S/N = 3), and it exhibited good reproducibility (< 6.2%). Recoveries ranging from 79% to 106%, with a relative standard deviation of < 6.7%, were obtained for all analytes. Fiber-to-fiber reproducibility (RSD), obtained using three fibers, was < 8.8%. The developed strategy combined the affinity of the polydimethylsiloxane coating towards amphetamine-type stimulants with the electrical conductivity of the stainless steel wire, effectively improving the enrichment ability and detection sensitivity, and achieving simultaneous selective enrichment and detection of several analytes. This is a simple, efficient, and reliable method for the analysis of amphetamine-type stimulants from complex matrices.