title: Rapid detection of drugs in biofluids using atmospheric pressure chemi/chemical ionization mass spectrometry.
abstract: We have demonstrated that, with simple pH adjustment, volatile drugs such as methamphetamine, amphetamine, 3,4-methylenedioxymethamphetamine (MDMA), ketamine, and valproic acid could be analyzed rapidly from raw biofluid samples (e.g. urine and serum) without dilution, or extraction, using atmospheric pressure ionization. The ion source was a variant type of atmospheric pressure chemical ionization (APCI) that used a dielectric barrier discharge (DBD) to generate the metastable helium gas and reagent ions. The sample solution was loaded in a disposable glass pipette, and the volatile compounds were purged by nitrogen gas to be reacted with the metastable helium gas. The electrodes of the DBD were arranged in such a way that the generated glow discharge was confined within the discharge tube and was not exposed to the analytes. A needle held at 100-500 V was placed between the ion-sampling orifice and the discharge tube to guide the analyte ions into the mass spectrometer. After pH adjustment of the biofluid sample, the amphiphilic drugs were in the form of a water-insoluble oil, which could be concentrated on the liquid surface. By gentle heating of the sample to increase the evaporation rate, rapid and sensitive detection of these drugs in raw urine and serum samples could be achieved in less than 2 min for each sample.
authors.affiliation: Clean Energy Research Center, University of Yamanashi, 4-3-11 Takeda, Kofu, Yamanashi 400-8511, Japan.
authors.forename: Lee Chuin
authors.initials: LC
authors.lastname: Chen
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Hashimoto
authors.forename: Hiroko
authors.initials: H
authors.lastname: Furuya
authors.forename: Kenichi
authors.initials: K
authors.lastname: Takekawa
authors.forename: Takeo
authors.initials: T
authors.lastname: Kubota
authors.forename: Kenzo
authors.initials: K
authors.lastname: Hiraoka
mesh_terms: D000662:Amphetamines / Q000097:blood / Q000652:urine; D001274:Atmospheric Pressure; D006801:Humans; D007477:Ions / Q000737:chemistry; D007649:Ketamine / Q000097:blood / Q000652:urine; D013058:Mass Spectrometry / Q000295:instrumentation / Q000379:methods; D008956:Models, Chemical; D012015:Reference Standards; D012680:Sensitivity and Specificity; D015813:Substance Abuse Detection / Q000379:methods; D014635:Valproic Acid / Q000097:blood / Q000652:urine; D055549:Volatile Organic Compounds / Q000097:blood* / Q000652:urine*
chemical_list: D000662:Amphetamines; D007477:Ions; D055549:Volatile Organic Compounds; D014635:Valproic Acid; D007649:Ketamine