Journal of Forensic Medicine ›› 2026, Vol. 42 ›› Issue (3): 261-268.DOI: 10.12116/j.issn.1004-5619.2025.350801

• Original Articles • Previous Articles     Next Articles

Enzyme Digestion LC-MS/MS Detection of Etomidate, Ketamine, Methamphe‑ tamine and Codeine in Hair

Mingjin YANG1(), Meiyun HE2, Weian DU3, Pengfei MEI1, Xuelian CHENG2, Xin LIU1, Yuesen SHI1, Hao JIN1, Yiling HU1, Meixin HE1, Ling CHEN2, Chao LIU1,4()   

  1. 1.Guangdong Provincial Key Laboratory of Psychoactive Substances Monitoring and Safety, Anti-Drug Technology Center of Guangdong Province, National Anti-Drug Laboratory Guangdong Regional Center, Guangzhou 510230, China
    2.School of Forensic Medicine, Southern Medical University, Guangzhou 510515, China
    3.Zhuhai Xiangzhen Biotechnology Co. , Ltd. , Zhuhai 519000, Guangdong Province, China
    4.State Key Laboratory of Bioactive Molecules and Druggability Assessment, Guangdong Provincial Basic Research Center of Excellence for Natural Bioactive Molecules and Discovery of Innovative Drugs, Jinan University, Guangzhou 510632, China
  • Received:2025-08-04 Online:2026-09-09 Published:2026-06-25
  • Contact: Chao LIU

Abstract:

Objective To establish a liquid chromatography-tandem mass spectrometry (LC-MS/MS)method based on enzymatic digestion for the rapid qualitative and quantitative detection of drugs in hair. Methods The enzymatic digestion parameters for etomidate, ketamine, methamphetamine, and codeine, including dithiothreitol (DTT) concentration, proteinase K concentration, incubation temperature and digestion time were optimized using controlled-variable experiments. After digestion, hair samples were filtered through a 0.22 μm membrane and separated on a C18 column with a gradient elution using 0.1% formic acid in water and 0.1% formic acid in acetonitrile and analyzed using electrospray ionization (ESI) in multiple reaction monitoring (MRM) mode. After validation, the method was applied to 155 drug-related hair samples and compared with the cryogenic wet-grinding method. Results Etomidate, ketamine, methamphetamine, and codeine in hair samples all showed good linearity with their respective linear ranges (R2>0.998 0), with limits of detection (LOD) of 0.005-0.010 ng/mg and limits of quantification (LOQ) of 0.02-0.04 ng/mg. Matrix effects ranged from -12.09% to 8.23%, while the relative standard deviations of intra-day precision and inter-day precision were 2.56%-10.37% and 5.50%-15.11%, respectively. Average recoveries (88.97%-104.05%) met analytical requirements. Results from drug-related hair samples suggested good consistency between enzymatic digestion and cryogenic grinding pretreatment method, while enzymatic digestion demonstrated higher extraction amounts for codeine than cryogenic grinding pretreatment method. Conclusion The established method is simple to operate, highly sensitive, and reproducible, making it suitable for high-throughput hair drug analysis, providing an efficient and reliable analytical method for forensic identification.

Key words: forensic medicine, toxicological analysis, hair analysis, enzymatic digestion method, LC-MS/MS, drugs

CLC Number: