title: [Determination of doxepin in whole blood by SPE-LC-MS/MS].
abstract: OBJECTIVE
  To develop a method of SPE-LC-MS/MS for the determination of doxepin in whole blood.
  
  
  METHODS
  After solid phase extraction, the samples were identified by LC-MS/MS. Positive ion electrospray ionization mode and multiple reaction monitoring (MRM) mode was selected. Amitriptyline was used as internal standard. The m/z of doxepin: 280-->107, 280-->235 and 280-->220. The m/z of amitriptyline: 278-->233. The retaining time of doxepin and amitriptyline were 15.15 and 16.94 min, respectively.
  
  
  RESULTS
  The calibration curve was linear among the concentration of doxepin range from 0.005 to 1.00 microg/mL. The linear correlation equation was y = 3.2047x + 0.0339, the correlation coefficient was 0.9996. The detection limit of doxepin was 0.001 microg/mL and average recovery rate was 78.0%-82.9%. The relative standard precision for within-day and between-day were less than 2.55% and 5.90%, respectively.
  
  
  CONCLUSIONS
  The method is effective, simple, reliable and can be used in the determination of doxepin in whole blood.
authors.affiliation: Shanghai Key Laboratory of Crime Scene Evidence, Institute of Forensic Science, Shanghai Public Security Bureau, Shanghai 200083, China.
authors.forename: Fei-Jun
authors.initials: FJ
authors.lastname: Gong
authors.forename: Song-Mao
authors.initials: SM
authors.lastname: Yan
authors.forename: Zhong-Ping
authors.initials: ZP
authors.lastname: Wu
authors.forename: Run-Sheng
authors.initials: RS
authors.lastname: Zhang
mesh_terms: D000639:Amitriptyline / Q000097:blood; D000929:Antidepressive Agents, Tricyclic / Q000097:blood* / Q000506:poisoning; D015415:Biomarkers / Q000032:analysis / Q000097:blood; D002853:Chromatography, Liquid / Q000379:methods*; D004316:Doxepin / Q000097:blood* / Q000506:poisoning; D062787:Drug Overdose; D053593:Forensic Toxicology; D006801:Humans; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D052616:Solid Phase Extraction / Q000379:methods*; D021241:Spectrometry, Mass, Electrospray Ionization; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D000929:Antidepressive Agents, Tricyclic; D015415:Biomarkers; D004316:Doxepin; D000639:Amitriptyline