title: Simultaneous extraction of acidic and basic drugs from urine using mixed-mode monolithic silica spin column bonded with octadecyl and cation-exchange group.
abstract: A method coupling spin column extraction with gas chromatography-mass spectrometry was developed for the simultaneous extraction of acidic and basic drugs from urine. Benzodiazepines, local anaesthetics, antidepressants, and barbiturates were used as model drugs. Sample loading, washing, and elution of the target drugs were accomplished by centrifugation of the column. In this study, mixed-mode monolithic silica bonded with a C18 reversed-phase and a strong cation exchange phase was packed in a spin column. The pH of a urine sample (0.2 mL) was adjusted to 3 and the analytes adsorbed onto the column were eluted with 0.1 mL of MeOH containing 2% NH3; all the tested drugs were simultaneously extracted from urine. The recovery of the tested drugs was 65-123%. Up to a concentration of 2500 ng/mL of the target drugs in urine, a linear curve was observed (r(2)>0.996). The intra- and interday RSDs at three different concentrations in urine were 2.1-14.7%. For RSDs lower than 15%, the limits of detection were 1-25 ng/mL. The proposed method was successfully applied for clinical and forensic cases and the results thus obtained were in good agreement with those obtained by conventional methods.
authors.affiliation: Department of Forensic Medicine, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan. namera@hiroshima-u.ac.jp.
authors.forename: Akira
authors.initials: A
authors.lastname: Namera
authors.forename: Shinobu
authors.initials: S
authors.lastname: Yamamoto
authors.forename: Takeshi
authors.initials: T
authors.lastname: Saito
authors.forename: Shota
authors.initials: S
authors.lastname: Miyazaki
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Oikawa
authors.forename: Akihiro
authors.initials: A
authors.lastname: Nakamoto
authors.forename: Masataka
authors.initials: M
authors.lastname: Nagao
mesh_terms: D002411:Cation Exchange Resins / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D013287:Illicit Drugs / Q000737:chemistry / Q000302:isolation & purification / Q000652:urine*; D012822:Silicon Dioxide / Q000737:chemistry; D052616:Solid Phase Extraction / Q000295:instrumentation / Q000379:methods*; D015813:Substance Abuse Detection
chemical_list: D002411:Cation Exchange Resins; D013287:Illicit Drugs; D012822:Silicon Dioxide