Re. Ostlund et al., QUANTIFICATION OF CHOLESTEROL TRACERS BY GAS CHROMATOGRAPHY-NEGATIVE ION CHEMICAL-IONIZATION MASS-SPECTROMETRY, Journal of mass spectrometry., 31(11), 1996, pp. 1291-1296
Because of its high sensitivity, gas chromatography negative ion chemi
cal ionization mass spectrometry (GC-NCI-MS) is a potentially valuable
analytical tool for the study of cholesterol metabolism, Of several d
erivatives prepared for potential use in tracer studies pentafluoroben
zoyl cholesterol was selected because it formed rapidly at ambient tem
perature and was stable for long periods, could be detected at a level
of 1 fmol, and yielded a mass spectrum in which the molecular ion was
the principal component, Hexadeuterated cholesterol tracer ([26,26,26
,27,27,27-H-2(6)]cholesterol) could be detected in dilutions up to 270
0 in unlabeled cholesterol by selected ion monitoring with a coefficie
nt of variation averaging 3.2%, In seven normal subjects tracer choles
terol was infused intravenously and plasma cholesterol enrichment was
determined after 4 h. The measured rapidly miscible cholesterol pool w
as 391.0 +/- 38.6 mg cholesterol/kg, Negative ion mass spectrometry of
pentafluorobenzyol cholesterol will facilitate analysis of both small
amounts of natural cholesterol and labeled cholesterol in application
s where sensitivity is critical.