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.
Detection of drugs of abuse in exhaled breath from users following recovery from intoxication.
It has recently been demonstrated that amphetamine, methadone and tetrahydrocannabinol are detectable in exhaled breath following intake. Exhaled breath, therefore, constitutes a new possible matrix for drugs-of-abuse testing. The present work aims to further explore this possibility by a study on patients treated for acute intoxication with abused drugs. Fifty-nine patients (44 males, age range 24-74) were included in the study, and breath, plasma and urine samples were collected following recovery, together with interview data. Analyses of breath and plasma samples were conducted with liquid chromatography-mass spectrometry methods. Urine was screened using immunochemical reagents and positive findings confirmed with liquid chromatography-mass spectrometry methods. The following analytes were investigated: methadone, amphetamine, methamphetamine, 3,4-methylenedioxymethamphetamine, codeine, 6-acetylmorphine, diazepam, oxazepam, morphine, benzoylecgonine, cocaine, buprenorphine and tetrahydrocannabinol. In 53 of the studied cases, recent intake of an abused substance prior to admission was reported. In 35 of these (66%), the breath analysis gave a positive finding. Identifications were based on correct chromatographic retention time and product ion ratios obtained in selected reaction monitoring mode. Generally, data from breath, plasma, urine and self-report were in agreement. Detected substances in breath included amphetamine, methamphetamine, buprenorphine, 6-acetylmorphine, morphine, codeine, methadone, tetrahydrocannabinol, diazepam, oxazepam and cocaine. Problem analytes with low detection rates were benzodiazepines and tetrahydrocannabinol. This study gives further support to the possibility of developing exhaled breath into a new matrix for drugs-of-abuse testing by extending the number of analytes that are documented to be detectable in breath.
Effects of temperature and humidity of inhaled air on the concentration of ethanol in a man's exhaled breath.
1. Ten healthy men each drank a moderate dose of ethanol in experiments to test if the temperature and moisture content of inhaled air could alter the concentration of ethanol in exhaled breath. 2. They breathed air at various temperatures and relative humidities (RH) for about 1 min before the concentration of ethanol and the temperature of end-expired breath were determined. Control breaths were analysed after the same men breathed ordinary room air (23°C, 55% RH). All tests were made during the postabsorptive phase of ethanol metabolism and the breath samples were analysed by gas-liquid chromatography. 3. When the men breathed cold dry air (5°C, 0% RH), the expired ethanol concentration decreased by 9·6 ± 0·69% (mean ± se) and breath temperature dropped by 1·40 ± 0·08°C. Cold moist air (5°C, 100% RH) decreased breath ethanol concentration by 6·4 ± 1·02% and breath temperature dropped by 1·1 ± 0·07°C. With hot dry air (80°C, 0% RH) as the breathing medium the concentration of ethanol was lowered by 4·3 ± 1·27% but expired breath temperatures were unchanged from the control tests. On breathing hot moist air (50°C, 100% RH), breath ethanol concentrations decreased by 10·3 ± 0·59%, even though breath temperatures rose by 1·8 ± 0·14°C above that of the controls. 4. Ethanol dissolves in the watery mucous membrane of the upper respiratory tract and can equilibrate with inhaled and exhaled air. It seems likely that during exchanges of heat and water vapour between respired air and the mucus, which largely depends on the temperature and humidity of inhaled air, the equilibrium of ethanol at the breath/mucus interface becomes disrupted. This leads to changes in the concentration of ethanol in expired air.