|Beck, Olof, Department of Medicine, section of Clinical Pharmacology, Karolinska Institutet, Stockholm, Sweden.|
Leine Kathinka, Department of Medicine, section of Clinical Pharmacology, Karolinska Institutet, Stockholm, Sweden.
Franck Johan, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.
Palmskog Göran, Department of Medicine, section of Clinical Pharmacology, Karolinska Institutet, Stockholm, Sweden. *Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.
Testing for drugs of abuse in sample matrices alternative to urine has received great attention in recent years. The interest and success of oral fluid testing in traffic medicine, workplace and clinical testing has demonstrated a need for tests based on simpler sampling than urine. Breath testing for alcohol is easily performed using portable instruments. Apart from alcohol it has not been demonstrated that expired air can be used for testing of any other drugs of abuse. However, expired air is known to contain a great number of substances including non-volatiles.
We undertook to investigate whether amphetamine could be detected in exhaled air from drug users by employing a most sensitive bioanalytical technology – SRM UPLC-MS/MS.
Methods: Twelve patients reporting recent use of amphetamine and seven healthy volunteers were recruited for this study. The self-reported drug intake was confirmed by analyses of blood and urine. Ethical approval was obtained. Compounds in expired air were sampled for 10 min by suction through an SPE cartridge (SPEC-DAS). The SPE cartridge was subsequently eluted with 2% ammonia in mixture of methanol and ethyl acetate (20/80). The eluate was evaporated and the residue subjected to analysis by SRM UPLC-MS/MS (Waters Quattro Premiere). The chromatographic system was a AQUITY UPLC BEH C18 column with a gradient system with A: 0.1% HCOOH in water and B: acetonitrile. The detection of two product ions per analyte was used by SRM in the positive electrospray mode.
In all 12 patients amphetamine and/or methamphetamine were detected in the sampled expired air. Identification of amphetamine was based on correct (relative to amphetamine-d5) retention time and correct (<±20%) ion intensity ratio between the two product ions. The amount of amphetamine/methamphetamine expired ranged from 0.3 to 139 pg/min. Amphetamine and methamphetamine were not detected in any of the samples from the seven healthy volunteers.
We conclude that this preliminary observation is promising and demonstrates that drug testing using exhaled air is possible and deserves further investigation. Expired air sampling might be more accessible and safe than any of the matrices used today.
Key words: Exhaled air, Drug testing, Amphetamine, UPLC-MS/MS