Automated Liquid-Liquid Extraction and Determination of Xylazine and Medetomidine in Plasma and Urine Samples

Xylazine and medetomidine are crucial to forensic scientists due to their roles as potent sedatives and analgesics commonly used in veterinary medicine but increasingly implicated in forensic investigations. Xylazine, often found in illicit drug mixtures, complicates toxicological analyses and poses serious health risks, including fatal overdoses when combined with opioids like fentanyl. Medetomidine, a selective α2-adrenergic agonist, is used in veterinary anesthesia and can be relevant in cases of accidental or intentional poisoning. The automated extraction and determination of compounds of forensic interest using the GERSTEL MultiPurpose Sampler (MPS) roboticPRO have been previously developed and discussed. This work shows that the same robotic sampler can be used to automate the extraction and determination of xylazine and medetomidine in plasma and urine samples.

The entire liquid-liquid extraction and subsequent analysis by LC-MS/MS is automated, providing critically needed high-throughput analysis for the abused drug compounds in either sample type. Using the GERSTEL MPS roboticPRO sampler, syringe transfer of all liquids involved in the liquid-liquid extraction and the controlled mixing, centrifugation, and evaporation of the samples for defined periods are performed. The resulting extracts are introduced into the Agilent Ultivo LC-MS/MS instrument for detection and quantification.