title: Determination of plasma bile acids by capillary gas-liquid chromatography-electron capture negative chemical ionization mass fragmentography.
abstract: Combined capillary gas-liquid chromatography-electron capture negative chemical ionization mass spectrometry of pentafluorobenzyl ester-TMSi ether derivatives of bile acids and isotope dilution using deuterated internal standards are introduced as a sensitive and selective analysis technique for plasma bile acids. As a result of the high ionization efficiency of pentafluorobenzyl derivatives under electron capturing conditions and minimal fragmentation, the detection limit of this technique is low: 1 pg for each bile acid. The high sensitivity enabled the detection and quantitation of atypical bile acids in 200-microliters aliquots of plasma from fasting healthy adults as exemplified by trihydroxycoprostanic acid (0.002 +/- 0.001 mumol/l) and dihydroxycoprostanic acid (0.013 +/- 0.002 mumol/l).
authors.affiliation: Department of Pediatrics, Free University Hospital, Amsterdam, The Netherlands.
authors.forename: F
authors.initials: F
authors.lastname: Stellaard
authors.forename: S A
authors.initials: SA
authors.lastname: Langelaar
authors.forename: R M
authors.initials: RM
authors.lastname: Kok
authors.forename: C
authors.initials: C
authors.lastname: Jakobs
mesh_terms: D000328:Adult; D000368:Aged; D001647:Bile Acids and Salts / Q000097:blood*; D005215:Fasting; D005464:Fluorobenzenes; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006801:Humans; D007202:Indicators and Reagents; D008875:Middle Aged; D014297:Trimethylsilyl Compounds; D005466:Fluorocarbons
chemical_list: D001647:Bile Acids and Salts; D005464:Fluorobenzenes; D007202:Indicators and Reagents; D014297:Trimethylsilyl Compounds; C025063:pentafluorobenzyl bromide; D005466:Fluorocarbons; C047270:N,N-bis(trimethylsilyl)-2,2,2-trifluoroacetamide