title: Application of accurate mass measurement to urine drug screening.
abstract: Poor availability of reference standards for designer drugs, metabolites, and new substances prevents toxicology laboratories from rapidly responding to the changing analytical challenges of drug abuse. A novel screening approach comprising determination of accurate masses of sample components and comparison of these with databases of theoretical monoisotopic masses is described. Using liquid chromatography-time-of-flight mass spectrometry (LC-TOFMS), a routine mass search window of 20-30 ppm was applied to urine samples. The ultimate reference technique, liquid chromatography-Fourier transform mass spectrometry (LC-FTMS), was capable of confirming the findings within a 3 ppm mass accuracy. Using a target database of 7640 compounds, the number of potential elemental formulas ranged from one to three with LC-TOFMS, and it was always one with LC-FTMS. In contrast to ordinary techniques requiring primary reference standards, the formula-based databases can be updated instantly with fresh numeric data from scientific literature and authority sources.
authors.affiliation: Department of Forensic Medicine, University of Helsinki, P.O. Box 40, FIN-00014, Helsinki, Finland. ilkka.ojanpera@helsinki.fi
authors.forename: Iikka
authors.initials: I
authors.lastname: Ojanperä
authors.forename: Anna
authors.initials: A
authors.lastname: Pelander
authors.forename: Suvi
authors.initials: S
authors.lastname: Laks
authors.forename: Merja
authors.initials: M
authors.lastname: Gergov
authors.forename: Erkki
authors.initials: E
authors.lastname: Vuori
authors.forename: Matthias
authors.initials: M
authors.lastname: Witt
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods; D005554:Forensic Medicine / Q000379:methods*; D006801:Humans; D004364:Pharmaceutical Preparations / Q000652:urine*; D012015:Reference Standards; D015203:Reproducibility of Results; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*
chemical_list: D004364:Pharmaceutical Preparations