Development and validation of a simple chromatographic method to screen oral fluid samples for drugs in DUID investigations.

A simple and rapid qualitative chromatographic method with a unique extraction approach was developed and validated to screen oral fluid samples for 31 compounds in driving under the influence of drugs investigations. The scope and sensitivity of the method meets or exceeds Tier I recommendations established by the National Safety Council's Alcohol, Drugs and Impairment Division. Since this is a targeted chromatographic screen (rather than an immunoassay), cutoffs were set to match the confirmation levels in the recommendations. Sample preparation involved a single-step liquid-liquid extraction procedure, using a mixture of methyl tert-butyl ether, isopropanol, and hexane and was applied to samples collected with the Quantisal™ device. Instrument analysis was conducted by liquid chromatography-tandem mass spectrometry, using a Restek Raptor™ biphenyl column for chromatographic separations and a total run time of 8 min. Validation results met all requirements of ANSI/ASB Standard 036 (1st edition)-Standard Practices for Method Validation in Forensic Toxicology.