Large-Scale Forensic Surveillance of Seized E-Liquids Reveals an Emerging Etomidate-Analog-Centered Vaping Trend in Eastern Taiwan.

The growing use of e-cigarettes as vehicles for illicit drug delivery has created an urgent challenge for forensic surveillance and public health in East Asia. This study analyzed 496 e-liquid samples seized by law-enforcement agencies in Eastern Taiwan (January-July 2025) using a full-scan GC-MS workflow validated in accordance with ANSI/ASB forensic toxicology standards. Overall, 80.8% of samples (n = 401) tested positive for psychoactive substances, with 35.4% (n = 142) containing polydrug mixtures. Etomidate dominated detections (87.0% of positive cases), followed by isopropoxate (25.4%), ketamine (9.7%), metomidate (8.5%), propoxate (7.2%), and methamphetamine (7.2%); cannabinoids (Δ9-THC and Δ8-THC) were comparatively rare (2.0% each). Predominant polydrug profiles included sedative-analog, sedative-dissociative, and sedative-stimulant combinations of acute toxicological concern. The present Eastern Taiwan dataset revealed a distinct etomidate-analog-centered adulterant profile, in marked contrast to the cannabinoid-dominated patterns reported in published seizure datasets from North America, Europe, and the Middle East. To our knowledge, seized-e-liquid surveillance data of this scale have not previously been reported for Eastern Taiwan. These findings highlight the value of seized-material toxicology as an early-warning component of forensic surveillance and support adaptive, class-level regulatory responses to the rapidly evolving landscape of designer-anesthetic vaping.