Optimization and Validation of Ionic Liquid‐Assisted Extraction Coupled With Ultra‐High‐Performance Liquid Chromatography‐Tandem Mass Spectrometry for Enhanced Morphine Detection in Hair Samples

ABSTRACT Morphine detection in hair is critical for forensic and clinical toxicology, yet traditional methods face challenges in sensitivity and reliability. This study optimized and validated an ionic liquid (IL)‐assisted extraction method for enhanced morphine detection in hair samples, coupled with ultra‐high‐performance liquid chromatography‐tandem mass spectrometry. The types, dosages of ILs, and external extraction factors (temperature, pH, and extraction time) were systematically investigated. Among the four ILs tested, 1‐hexyl‐3‐methylimidazolium chloride at a concentration of 20 mg/mL exhibited superior extraction efficiency by disrupting the hydrogen bonds of hair keratin. The optimal external extraction conditions were determined as 30°C, pH 10, and an extraction time of 4 min. Under the optimized conditions, the method showed good linearity in the concentration range of 0.5–1000 ng/mL with a coefficient of determination greater than 0.99. The limit of detection, calculated at a signal‐to‐noise ratio of 3, was 0.11 ng/mg, and the relative standard deviation was 1.56%. Meanwhile, an average extraction recovery of 96.92% was achieved. Compared with traditional extraction methods, the IL‐assisted extraction method improved the detection efficiency of morphine by 26.85%–28.57% in hair samples from heroin users. This approach provides a robust, sensitive, and eco‐friendly analytical alternative for forensic and clinical toxicological applications.