Automated Liquid-Liquid Extraction and Determination of Abused OTC Compounds in Serum and Urine Samples

The forensic community has experienced an increasing emergence of New Psychoactive Substances (NPSs) in recent years. However, if these new psychoactive substances are unable to be obtained, users will attempt to achieve the same “high” by ingesting large doses of over-the-counter (OTC) medication. The most common of these abused drugs are dextrorphan, dextromethorphan, and diphenhydramine which are found in common cold medications. The automated extraction and determination of compounds of forensic interest using the GERSTEL MultiPurpose Sampler (MPS) roboticPRO have been previously developed and discussed. In this work, we show that the same robotic sampler can be used to automate the extraction and determination of abused OTC compounds in serum 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.