Fast saliva analysis by GC–MS with Cold EI and Open Probe Fast GC–MS with Cold EI for the detection of cannabis usage

Abstract

Saliva is a body fluid that is much easier to collect and analyze than blood. Thus, saliva analysis for the detection of delta 9‐tetrahydrocannabinol (delta 9‐THC) can serve as a tool for law enforcement agents to detect cannabis consumption by drivers. Fast saliva analysis for the presence of delta 9‐THC and/or cannabidiol (CBD) is described with both gas chromatography–mass spectrometry (GC–MS) with Cold electron ionization (EI) with good separation and in 10 min and/or with Open Probe Fast GC–MS with Cold EI in under 1 min full analysis cycle time. Saliva was taken directly from donors' tongues on a thin glass rod that was used “as is” for analysis. The saliva was thermally desorbed with a modified ChromatoProbe device inside the gas chromatograph (GC) injector and in an Open Probe (Agilent name QuickProbe) for its sub‐1‐min analysis. Cold EI is based on coupling of the GC and mass spectrometer (MS) with a supersonic molecular beam and on EI of vibrationally cold sample molecules during their flight through a contact‐free ion source (thereby named Cold EI). A revised type of Open Probe Fast GC–MS on the bench is also described. Our saliva analysis was characterized by: Saliva can be collected in the field and transported to the lab for analyses “as is” without any sample preparation. Easy detection of cannabis consumption from cigarettes and/or other cannabis products. Distinction between the isomers delta 9‐THC and CBD. Ultra‐fast analysis in under 1 min using Open Probe Fast GC–MS with Cold EI.