title: Simultaneous identification and quantitation of fluoxetine and its metabolite, norfluoxetine, in biological samples by GC-MS.
abstract: A sensitive method for the quantitation of fluoxetine and norfluoxetine in biological samples was developed. Blood, urine, and tissue samples were alkalinized and extracted with N-butyl chloride. The extracts were derivatized with pentafluoropropionic anhydride before gas chromatography-mass spectrometry (GC-MS). Selected ions were monitored at m/z 117 and 294 for fluoxetine; m/z 117, 176, and 280 for norfluoxetine; and m/z 122 and 299 for the internal standard fluoxetine-d5. The within-run and between-run precision as well as recovery were determined for both analytes. The empirical limit of detection was determined to be 12.5 micrograms/L for both fluoxetine and norfluoxetine, whereas the empirical limit of quantitation was 25 micrograms/L for both drugs. Calibration curves were linear in the range of 50-1000 micrograms/L for both analytes. Some drugs that were known or suspected of interfering with high-performance liquid chromatography and GC methods for fluoxetine and norfluoxetine were tested for interference. This is the only reported method that combines the use of a deuterated internal standard, selected ion monitoring by GC-MS, and derivatization for the identification and quantitation of fluoxetine and norfluoxetine.
authors.affiliation: St. Louis University, Forensic Toxicology Laboratory, Missouri 63134, USA.
authors.forename: J A
authors.initials: JA
authors.lastname: Crifasi
authors.forename: N X
authors.initials: NX
authors.lastname: Le
authors.forename: C
authors.initials: C
authors.lastname: Long
mesh_terms: D018687:Antidepressive Agents, Second-Generation / Q000032:analysis* / Q000097:blood / Q000652:urine; D002138:Calibration; D005473:Fluoxetine / Q000031:analogs & derivatives* / Q000032:analysis / Q000097:blood / Q000652:urine; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D011786:Quality Control; D012015:Reference Standards
chemical_list: D018687:Antidepressive Agents, Second-Generation; D005473:Fluoxetine; C036139:norfluoxetine