Detection of Δ9-tetrahydrocannabinol in exhaled breath collected from cannabis users.
Exhaled breath has recently been proposed as a new possible matrix for drugs of abuse testing. A key drug is cannabis, and the present study was aimed at investigating the possibility of detecting tetrahydrocannabinol and tetrahydrocannabinol carboxylic acid in exhaled breath after cannabis smoking. Exhaled breath was sampled from 10 regular cannabis users and 8 controls by directing the exhaled breath by suction through an Empore C(18) disk. The disk was extracted with hexane/ethyl acetate, and the resulting extract was evaporated to dryness and redissolved in 100 μL hexane/ethyl acetate. A 3-μL aliquot was injected onto the LC-MS-MS system and analyzed using positive electrospray ionization and selected reaction monitoring. In samples collected 1-12 h after cannabis smoking, tetrahydrocannabinol was detected in all 10 subjects. The rate of excretion was between 9.0 and 77.3 pg/min. Identification of tetrahydrocannabinol was based on correct retention time relative to tetrahydrocannabinol-d(3) and correct product ion ratio. In three samples, peaks were observed for tetrahydrocannabinol carboxylic acid, but these did not fulfill identification criteria. Neither tetrahydrocannabinol or tetrahydrocannabinol carboxylic acid was detected in the controls. These results confirm older reports that tetrahydrocannabinol is present in exhaled breath following cannabis smoking and extend the detection time from minutes to hours. The results further support the idea that exhaled breath is a promising matrix for drugs-of-abuse testing.
Breath analysis of cannabis smokers
Cannabis (dagga) grows so widely in South Africa that its control poses considerable problems. A simple screening test to detect cannabis smokers was sought but enquiry by one of us (van Zyl, 1970) revealed that no such test existed. To this end we have investigated the possibility of a “breathalyser”, and preliminary investigations have been encouraging. The suspect is required to breathe onto a paper (filter paper or tissue) freshly dampened with aqueous Fast Blue B salt 1 % w/v. Korte & Sieper (1964) state that this reagent has a sensitivity down to 0.01 pg by t.1.c.). The colour response is from bright orange-pink to deep orange-pink tinged with mauve up to 15 min after smoking and a colour is obtainable up to 2 h after one typical cannabis cigarette. Colour formation is sometimes not instantaneous. South African cannabis is potent (de Faubert Maunder, 1970, Fairbairn, Liebmann & Simic, 1971) so that the response might well be weaker elsewhere. We have investigated substances that might interfere, but items like spices and peppermints, give only the faintest response. A positive result can immediately be followed by testing any found material using Fast Blue B (de Faubert Maunder, 1969 a) and confirmed in the laboratory. Two simple colour tests, the first using Fast Blue B and the second “Meta” Duquenois reagent have been described for almost specific identification (de Faubert Maunder, 1969 b). Both Betts & Holloway (1967) and de Faubert Maunder (1969 a) when investigating cannabis, found no interference from tobacco. In South Africa, however, there are brands of toasted cigarettes which with Fast Blue B gives a marked and similar reaction to cannabis from the smoke itself, but not from light petroleum extracts of the tobacco. Some cigars give a deep yellow orange, although only from fresh smoke. Smoked tobacco also gives a false positive, but if the remaining tobacco in benzene is chromatographed as described below, false positives fade if left overnight whereas the cannabis colour does not. An attempt to elute the smoke dye complex with ether followed by t.1.c. on silica gel (Merck Kieselgel F254) using benzene-ethanol (5 : 1) showed that the cannabis-dye complex and tobacco smoke-dye ran to similar RF values. However, if cannabis smoke and the smoke of two toasted cigarettes were separately drawn through filter discs (Cambridge CM-113, 1.5 mm thick) and the tar thus collected was eluted with ether and chromatographed on silica gel using benzene, on spraying with Fast Blue B, the discs showed that only the cannabis had run (RF 0.63), giving a spot suggesting cannabinol and tetrahydrocannabinol (de Faubert Maunder, 1969 c). Nutmeg, gives a similar colour with the reagent, and spreads to an RF of about 0.2, while thymol, which gives a deep masking orange, is at RF 0.5; menthol neither ran nor gave a colour when sprayed. The nutmeg and smoked tobaccos were applied as light petroleum extracts, thymol and menthol as ethanolic solutions. It is possible to extract and chromatograph the dye-complex from filter paper many days after the test. The need is a suitable solvent system which eliminates toasted tobacco.
Identification of Dihydroxy Aromatic Compounds in a Low-Temperature Pyrolysis Coal Tar by Gas Chromatography−Mass Spectrometry (GC−MS) and Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR MS)
Dihydroxy aromatics in coal tar undergo rapid coupling reactions with each other and with some coal-derived species during coal pyrolysis and liquefaction. However, only limited information on the structure of dihydroxy aromatics is known. In this study, Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and gas chromatography−mass spectrometry (GC−MS) were used to characterize the dihydroxy aromatics in a low-temperature pyrolyzed coal tar and its distillate and residue fractions. Negative-ion electrospray ionization (ESI) FT-ICR MS spectra of coal-tar-derived samples had low molecular masses and narrow mass ranges. Negative-ion ESI is extremely selective for the dihydroxy aromatics present in coal tar. The O2 class species had the highest ion intensity among the species in the negative-ion FT-ICR mass spectrum for each sample. Dihydroxy compounds with an aromatic core structure of benzene, indan, biphenyl (and/or acenaphthene), and naphthalene were identified in the distillate fract...