A rapid and non-invasive method to determine toxic levels of alcohols and γ-hydroxybutyric acid in saliva samples by gas chromatography-differential mobility spectrometry.

A polydimethylsiloxane oral sampler was used to extract methanol, ethanol, ethylene glycol, 1,3-propandiol and γ-hydroxybutyric acid from samples of human saliva obtained using a passive drool approach. The extracted compounds were recovered by thermal desorption, isolated by gas chromatography and detected with differential mobility spectrometry, operating with a programmed dispersion field. Complex signal behaviours were also observed that were consistent with hitherto unobserved fragmentation behaviours in differential mobility spectrometry. These yielded high-mobility fragments obscured within the envelope of the water-based reactant ion peak. Further, compensation field maxima shifts were also observed which were attributable to transport gas modification phenomena. Nevertheless, the responses obtained indicated that in vivo saliva sampling with thermal desorption gas chromatography may be used to provide a semi-quantitative diagnostic screen over the toxicity threshold concentration ranges of 100 mg dm(-3) to 3 g dm(-3). A candidate method suitable for use in low resource settings for the non-invasive screening of patients intoxicated by alcohols and volatile sedatives has been demonstrated.