An Efficient, Robust Method for the Determination of Cannabinoids in Whole Blood by LC-MS-MS.
Due to the high prevalence of cannabinoids in forensic toxicology casework, it is desirable to have an efficient method that uses a small volume of blood and requires a minimal sample preparation. Although many methods have been reported, they are often labor intensive, require special sample preparation materials, use 1 mL or more of specimen or are difficult to replicate. The liquid chromatography with tandem mass spectrometry (LC-MS-MS) method presented herein employs a rapid and simple liquid-liquid extraction, has been successfully applied in two different laboratories, uses 0.5 mL of specimen and was extensively validated. The validated limit of detection and limit of quantitation were 1 ngmL for delta-9-tetrahydrocannabinol (THC) and 11-hydroxy-delta-9-tetrahydrocannabinol (OH-THC) and 5 ngmL for 11-nor-9-carboxy-delta-9-tetrahydrocannabinol (THCA). Each analyte demonstrated a zero-order linear range (r