title: Method validation and application of a liquid chromatography-tandem mass spectrometry method for drugs of abuse testing in exhaled breath.
abstract: A mass spectrometric method for drugs of abuse testing in exhaled breath employing a sampling device collecting aerosol particles was developed and applied in routine use. Analytes covered were amphetamine, methamphetamine, 6-acetylmorphine, morphine, cocaine, benzoylecgonine, diazepam, oxazepam and tetrahydrocannabinol. The method involved eluting drugs from the collection filter with methanol, quantification using deuterated analogs as internal standards, reversed phase chromatography with gradient elution, positive electrospray ionization and monitoring of two product ions per analyte in selected reaction monitoring mode. The measuring range was 6.0-1000pg/filter. The intra- and inter-assay imprecision expressed as the coefficient of variation was less than 7%. Influence from matrix was noted for most compounds but was compensated for the use of co-eluting internal standards. The LLOQ was 6.0pg/filter with intra-assay CV <5% and accuracy within 99-102% for all analytes. No chromatographic interference was observed in 20 negative control samples. The LC-MS/MS method was successfully applied for measuring drugs in unknown samples collected for the purpose of drug testing. Among the 1096 analyzed samples analytical findings were made in breath in 39 cases (3.6%). Most frequently found substances were the following: amphetamine (25 cases) methamphetamine (10 cases), THC (8 cases), cocaine (4 cases), benzoylecgonine (2 cases) and diazepam (2 cases). In conclusion, a fully validated and robust screening method suitable for the routine measurement of drugs of abuse in exhaled breath with a simple procedure for specimen collection and sample preparation was successfully developed.
authors: Department of Laboratory Medicine, Section of Clinical Pharmacology, Karolinska Institutet, Stockholm, Sweden. Electronic address: niclas.stephanson@karolinska.se.
authors: Niclas
authors: N
authors: Stephanson
authors: Department of Laboratory Medicine, Section of Clinical Pharmacology, Karolinska Institutet, Stockholm, Sweden.
authors: Sören
authors: S
authors: Sandqvist
authors: Department of Laboratory Medicine, Section of Clinical Pharmacology, Karolinska Institutet, Stockholm, Sweden.
authors: Marjan Shafaati
authors: MS
authors: Lambert
authors: Department of Laboratory Medicine, Section of Clinical Pharmacology, Karolinska Institutet, Stockholm, Sweden.
authors: Olof
authors: O
authors: Beck
mesh_terms: D001944:Breath Tests / Q000379:methods*; D002853:Chromatography, Liquid / Q000379:methods*; D006801:Humans; D013287:Illicit Drugs / Q000032:analysis*; D016014:Linear Models; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D013287:Illicit Drugs
keywords: Drugs of abuse testing; Exhaled breath; LC–MS/MS