title: A sensitive high-pressure liquid chromatography/particle beam/mass spectrometry assay for the determination of all-trans-retinoic acid and 13-cis-retinoic acid in human plasma.
abstract: A highly sensitive assay for the measurement of all-trans-retinoic acid (tretinoin) and 13-cis-retinoic acid (isotretinoin) has been developed. Collected plasma samples were protein precipitated with 2-propanol followed by solid phase extraction. The retinoic acids were subsequently derivatized to their pentafluorobenzyl esters followed by separation and isolation by reverse phase high-pressure liquid chromatography. The HPLC eluate was directed to a mass spectrometer via a particle beam interface. Selected ion monitoring (299 m/z) for the retinoic acid's carboxylate anion produced by negative chemical ionization using methane reagent gas achieved minimum detection limits of 25 pg injected. Endogenous blood levels in 19 male and 9 female subjects were measured. It was found that females have significantly more all-trans-retinoic acid than males and that both sexes demonstrate significantly more all-trans-retinoic acid then 13-cis-retinoic acid.
authors.affiliation: Department of Dermatology, University of Arkansas for Medical Sciences, Little Rock 72205-7199, USA.
authors.forename: P A
authors.initials: PA
authors.lastname: Lehman
authors.forename: T J
authors.initials: TJ
authors.lastname: Franz
mesh_terms: D000328:Adult; D001774:Blood Chemical Analysis; D002851:Chromatography, High Pressure Liquid; D005260:Female; D006801:Humans; D015474:Isotretinoin / Q000097:blood*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D014212:Tretinoin / Q000097:blood*
chemical_list: D014212:Tretinoin; D015474:Isotretinoin