Drug Abuse Tests Mouth Off
Thu, 11/04/2010 - 5:36am
by Eric Chi and Jason Cole, Thermo Fisher Scientific, Austin, TX
The marijuana plant contains a pharmacologically active compound—?9-tetrahydrocannabinol (THC)—known to have mind-altering properties. Since marijuana is one of the most commonly used illegal drugs, THC analysis in oral fluid is becoming increasingly important, however this type of analysis can be particularly challenging due to the low concentration of THC typically found in oral fluid, as well as the low volumes of oral fluid that are generally available for analysis. Like many biological fluids, the chemical background from the oral fluid matrix can limit the low detection levels required for this analysis.
The use of gas chromatography coupled with a triple quadrupole mass spectrometer overcomes many of these challenges. To demonstrate the capabilities of this technique, a method for the detection of THC in an oral fluid matrix was fully validated for linearity, precision and carryover. A Thermo Scientific TSQ Quantum GC analyzer was selected over a single quadrupole due to its ability to detect analytes to very low quantitation limits in complex matrices. Thermo Scientific ToxLabs Forms 2.5.1 software was used for sample analysis and quantitation, as well as method validation.
Table 1. The sequence noted in this table summarizes the sample preparation, extraction, and derivatization steps used prior to loading the sample onto an autosampler for GCMS analysis. Click to enlarge.