title: High-throughput simultaneous analysis of five urinary metabolites of areca nut and tobacco alkaloids by isotope-dilution liquid chromatography-tandem mass spectrometry with on-line solid-phase extraction.
abstract: BACKGROUND
  Areca nut and tobacco are commonly used drugs worldwide and have been frequently used in combination. We describe the use of on-line solid-phase extraction and isotope-dilution liquid chromatography-tandem mass spectrometry for the simultaneous measurement of five major urinary metabolites of both areca nut and tobacco alkaloids, namely, arecoline, arecaidine, N-methylnipecotic acid, nicotine, and cotinine.
  
  
  METHODS
  Automated purification of urine was accomplished with a column-switching device. After the addition of deuterium-labeled internal standards, urine samples were directly analyzed within 13 minutes. This method was applied to measure urinary metabolites in 90 healthy subjects to assess areca nut/tobacco exposure. Urinary time course of arecoline, arecaidine, and N-methylnipecotic acid was investigated in five healthy nonchewers after oral administration of areca nut water extracts.
  
  
  RESULTS
  The limits of detection were 0.016 to 0.553 ng/mL. Interday and intraday imprecision were <10%. Mean recoveries of five metabolites in urine were 97% to 114%. Mean urinary concentrations of arecoline, arecaidine, N-methylnipecotic acid, nicotine, and cotinine in regular areca nut chewers also smokers were 23.9, 5,816, 1,298, 2,635, and 1,406 ng/mg creatinine, respectively. Time course study revealed that after administration of areca nuts extracts, the major urinary metabolite was arecaidine with a half-life of 4.3 hours, followed by N-methylnipecotic acid with a half-life of 7.9 hours, and very low levels of arecoline with a half-life of 0.97 hour.
  
  
  CONCLUSIONS
  This on-line solid-phase extraction liquid chromatography-tandem mass spectrometry method firstly provides high-throughput direct analysis of five urinary metabolites of areca nut/tobacco alkaloids.
  
  
  CONCLUSIONS
  This method may facilitate the research into the oncogenic effects of areca nut/tobacco exposure.
authors: Department of Public Health, Chung Shan Medical University, Taichung 402, Taiwan.
authors: Chiung-Wen
authors: CW
authors: Hu
authors: Yan-Zin
authors: YZ
authors: Chang
authors: Hsiao-Wen
authors: HW
authors: Wang
authors: Mu-Rong
authors: MR
authors: Chao
mesh_terms: D000328:Adult; D001114:Areca; D001115:Arecoline / Q000031:analogs & derivatives* / Q000652:urine*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003367:Cotinine / Q000652:urine*; D003430:Cross-Sectional Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009538:Nicotine / Q000652:urine*; D012907:Smoking / Q000652:urine; D052616:Solid Phase Extraction / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*; D014026:Nicotiana; D055815:Young Adult
chemical_list: C015688:arecaidine; D001115:Arecoline; D009538:Nicotine; D003367:Cotinine