title: Preparation of longitudinal sections of hair samples for the analysis of cocaine by MALDI-MS/MS and TOF-SIMS imaging.
abstract: Matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) for the analysis of intact hair is a powerful tool for the detection of drugs of abuse in toxicology and forensic applications. Here we present a quick, easy, and reproducible method of preparing longitudinal sections of single hairs. This method improves the accessibility of chemicals embedded in the hair matrix for molecular imaging with mass spectrometry. The images obtained from a single, sectioned hair sample show molecular distributions in the exposed medulla, cortex, and a portion of the cuticle observed as a narrow layer surrounding the cortex. Using MALDI-MS/MS imaging, the distribution of cocaine was observed throughout five longitudinally sectioned drug-user hair samples. The images showed the distribution of the product ion at m/z 182, derived from the precursor ion of cocaine at m/z 304. MetA-SIMS images of longitudinally sectioned hair samples showed a more detailed distribution of cocaine at m/z 304, benzoylecgonine the major metabolite of cocaine at m/z 290 and other drugs such as methadone which was observed at m/z 310. Chronological information of drug intake can be obtained more sensitively. The chronological detail is in hours rather than months, which is of great interest in clinical as well as forensic applications.
authors.affiliation: FOM-Institute AMOLF, Science Park 104, 1098 XG, Amsterdam, the Netherlands.|M4I, The Maastricht MultiModal Molecular Imaging institute, University of Maastricht, Universiteitssingel 50, 6229 ER, Maastricht, the Netherlands.
authors.forename: Bryn
authors.initials: B
authors.lastname: Flinders
authors.affiliation: KU Leuven Toxicology and Pharmacology, Herestraat 49, PO 922, 3000, Leuven, Belgium.
authors.forename: Eva
authors.initials: E
authors.lastname: Cuypers
authors.affiliation: FOM-Institute AMOLF, Science Park 104, 1098 XG, Amsterdam, the Netherlands.
authors.forename: Hans
authors.initials: H
authors.lastname: Zeijlemaker
authors.affiliation: KU Leuven Toxicology and Pharmacology, Herestraat 49, PO 922, 3000, Leuven, Belgium.
authors.forename: Jan
authors.initials: J
authors.lastname: Tytgat
authors.affiliation: FOM-Institute AMOLF, Science Park 104, 1098 XG, Amsterdam, the Netherlands.|M4I, The Maastricht MultiModal Molecular Imaging institute, University of Maastricht, Universiteitssingel 50, 6229 ER, Maastricht, the Netherlands.
authors.forename: Ron M A
authors.initials: RM
authors.lastname: Heeren
mesh_terms: D003042:Cocaine / Q000031:analogs & derivatives / Q000032:analysis*; D018765:Dopamine Uptake Inhibitors / Q000032:analysis*; D004867:Equipment Design; D006197:Hair / Q000737:chemistry*; D006801:Humans; D013048:Specimen Handling / Q000295:instrumentation; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D015813:Substance Abuse Detection / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods
chemical_list: D018765:Dopamine Uptake Inhibitors; C005618:benzoylecgonine; D003042:Cocaine
keywords: MALDI-MSI; MetA-SIMS; cocaine; hair analysis; longitudinal sectioning