title: The analysis of 5-fluorouracil in human plasma by gas chromatography-negative ion chemical ionization mass spectrometry (GC-NICIMS) with stable isotope dilution.
abstract: 5-Fluorouracil (5-FU) was extracted from plasma and converted to its di-N-ditrifluoromethylbenzyl (DTFMBz) derivative by treatment with DTFMBzBr. Under negative ion chemical ionization (NICI) conditions the derivative yielded a mass spectrum in which most of the ion current was carried by the M(-)-DTFMBz ion (m/z 355). Selected ion monitoring enabled detection of this derivative in amounts less than 1 pg, and the practical limit of detection for 5-FU extracted from plasma was ca 400 pg ml-1. 5-FU was quantified by adding a fixed amount of [15N2]5-FU to samples of plasma before extraction, and comparing the ratio of the ions of m/z 355 and 357 against a calibration curve constructed over the concentration range under investigation. The method was used to measure the variation in the concentration of 5-FU with time during continuous infusion of the drug via three, different protocols in patients with hepatic tumour.
authors.affiliation: Department of Pharmacy, University of Strathclyde, Glasgow, UK.
authors.forename: C D
authors.initials: CD
authors.lastname: Bates
authors.forename: D G
authors.initials: DG
authors.lastname: Watson
authors.forename: N
authors.initials: N
authors.lastname: Willmott
authors.forename: H
authors.initials: H
authors.lastname: Logan
authors.forename: J
authors.initials: J
authors.lastname: Goldberg
mesh_terms: D005472:Fluorouracil / Q000097:blood*; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans
chemical_list: D005472:Fluorouracil