title: A screening method for 30 drugs in hair using ultrahigh-performance liquid chromatography time-of-flight mass spectrometry.
abstract: OBJECTIVE
  The objectives of this study were to develop and to validate a qualitative screening method that met the new Society of Hair Testing (SoHT) guideline criteria for thresholds.
  
  
  METHODS
  Extraction of 20 mg hair was performed by a previously validated procedure using overnight incubation in a mixture of methanol:acetonitrile:formiate buffer pH 3 (10:10:80). Analysis was performed on an Agilent 6540 quadrupole time-of-flight mass spectrometer in combination with an Agilent 1290 Infinity ultrahigh-performance liquid chromatography system. Separation was achieved with a 12-minute linear gradient chromatography on a high-strength silica T3 column at acidic conditions. An in-house database containing 30 compounds from the groups amphetamines, opiates, opioids, cocaine, benzodiazepines, and other sedatives including 6 deuterated internal standards was built by analyzing solutions from certified standards. Data were extracted using mass accuracy of ± 10 ppm, retention time deviation of ± 0.15 minutes, and area of ≥ 30,000 counts. Identification was based on scoring of retention time, accurate mass measurement, and isotopic pattern. Validation included selectivity, repeatability of analyte area, and the scoring parameters at the proposed thresholds and a method comparison with the present liquid chromatography-mass spectrometry-mass spectrometry method using 50 authentic hair samples. A daily cutoff calibrator was used to identify positive samples.
  
  
  RESULTS
  All cutoffs could be met with imprecisions of less than 5% for most parameters and analytes. Hair from drug-free subjects did not produce any positive results and the method comparison agreed in more than 90% of the cases.
  
  
  CONCLUSIONS
  We conclude that the developed method meets the criteria of the new SoHT guidelines for screening cutoffs. Even though no thresholds have been suggested for benzodiazepines, we conclude that thresholds between 0.05 and 0.1 ng/mg should be sufficient to determine regular use of these substances.
authors.affiliation: Department of Forensic Genetics and Forensic Toxicology, National Board of Forensic Medicine, Linköping, Sweden. robert.kronstrand@rmv.se
authors.forename: Robert
authors.initials: R
authors.lastname: Kronstrand
authors.forename: Malin
authors.initials: M
authors.lastname: Forsman
authors.forename: Markus
authors.initials: M
authors.lastname: Roman
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D016208:Databases, Factual; D053593:Forensic Toxicology / Q000379:methods; D017408:Guidelines as Topic; D006197:Hair / Q000737:chemistry*; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods*; D015203:Reproducibility of Results; D015813:Substance Abuse Detection / Q000379:methods*