title: Determination of subnanogram concentrations of fentanyl in plasma by gas chromatography-mass spectrometry: comparison with standard radioimmunoassay.
abstract: A method was devised to determine fentanyl plasma concentrations by GC-MS using selected-ion monitoring (SIM) with sufentanil as internal standard. This was compared with a commonly used commercial radioimmunoassay (RIA). Sample preparation for GC-MS involved basification of plasma then extraction using n-butyl chloride followed by concentration to dryness and reconstitution in toluene for chromatography. Using 1-ml plasma samples, the estimated limit of detection of fentanyl was 20 pg/ml. Blood samples for pharmacokinetic studies were split and assayed by GC-MS and RIA which had a limit of detection of 200 pg/ml. Pearson's r (r - 0.80, p < 0.0001) indicated the methods were highly correlated at all plasma concentrations. Owing to the greater sensitivity of the method, GC-MS is recommended over RIA for subnanogram determination of fentanyl in plasma.
authors.affiliation: Department of Anaesthesia and Pain Management, University of Sydney, Royal North Shore Hospital, St Leonards, NSW, Australia.
authors.forename: B
authors.initials: B
authors.lastname: Fryirs
authors.forename: A
authors.initials: A
authors.lastname: Woodhouse
authors.forename: J L
authors.initials: JL
authors.lastname: Huang
authors.forename: M
authors.initials: M
authors.lastname: Dawson
authors.forename: L E
authors.initials: LE
authors.lastname: Mather
authors.forename: B
authors.initials: B
authors.lastname: Fryirsa
mesh_terms: D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000097:blood* / Q000737:chemistry / Q000493:pharmacokinetics; D005283:Fentanyl / Q000008:administration & dosage / Q000097:blood* / Q000737:chemistry / Q000493:pharmacokinetics; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006801:Humans; D007275:Injections, Intravenous; D011863:Radioimmunoassay; D011933:Reagent Kits, Diagnostic; D012680:Sensitivity and Specificity
chemical_list: D000701:Analgesics, Opioid; D011933:Reagent Kits, Diagnostic; D005283:Fentanyl