Thermo Fisher Scientific Achieves Superior Precision and Linearity in High-Throughput, Trace Level Analyses of THC in Oral Fluid Using the TSQ Quantum GC Analyzer

Oral fluid analysis is becoming an increasingly popular alternative to blood and urine testing for the detection of drugs, such as marijuana. Oral fluid can be collected and monitored without embarrassment, pain, or the extensive training required to draw blood. Since ?9-tetrahydrocannabinol (THC), the pharmacologically active compound found in marijuana, is one of the most commonly used illegal drugs, its analysis in oral fluid has become imperative. This analysis can be extremely challenging due to the low concentrations of THC typically found in oral fluid and the low volumes of oral fluid that are generally available for analysis. In addition, the chemical background from the oral fluid matrix can limit the low detection levels required for this analysis. The Thermo Scientific TSQ Quantum GC overcomes these challenges, routinely measuring THC in oral fluid at a 2 ng/mL cutoff level and below with minimal matrix interferences.

Methods were developed for sample preparation, acquisition and analysis for this forensic toxicology assay. Experimental results demonstrate that the analyzer, operated in multiple reaction monitoring (MRM) mode, is both selective and sensitive enough for accurate trace THC measurements in oral fluid. In addition, the TSQ Quantum GC achieves superior quantitative precision, with coefficients of variation (CV) of 6% or less at 0.8 and 2.5 ng/mL and exceptional linearity and accuracy from 0.2 to 20 ng/mL with no significant carryover.

All method development and validation were performed in an extracted oral fluid calibrating matrix, proving the real world capability of the Thermo Scientific TSQ Quantum GC to perform dependable monitoring of trace levels of THC in oral fluid. In addition, Thermo Scientific ToxLab Forms 2.5 software provided automated sample analysis and quantitation and was used for method validation, including assessments of precision and linearity.