Micro-solid phase extraction coupled with high-performance liquid chromatography–tandem mass spectrometry for the determination of stimulants, hallucinogens, ketamine and phencyclidine in oral fluids

A confirmatory method for the determination of illicit drugs based on micro-solid phase extraction with modified tips, made of a functionalized fiberglass with apolar chains of octadecylsilane into monolithic structure, has been developed in this study. Drugs belonging to different chemical classes, such as amphetamine, methamphetamine, methylenedioxyamphetamine, methylenedioxyethylamphetamine, methylenedioxymethylamphetamine, cocaine, benzoylecgonine, ketamine, mescaline, phencyclidine and psilocybine were analyzed. The quantitation was performed by liquid chromatography–tandem mass spectrometry and the analytes were detected in positive ionization by means of an electrospray source. The limits of quantification ranged between 0.3 ng mL−1 for cocaine and 4.9 ng mL−1 for psilocybine, with coefficients of determination (r2) >0.99 for all the analytes as recommended in the guidelines of Society of Forensic Toxicologists-American Association Forensic Sciences.