title: Detection and quantification of lanosterol and dihydrolanosterol esters by measurements of metastable decompositions. Application to their direct analysis in wool wax.
abstract: The fatty acyl moiety in lanosterol and dihydrolanosterol esters was determined by measurement of the metastable transition [M--15]+ leads to [M--15-fatty acid]+ which occurs in the first field free region of a double focusing mass spectrometer. The analysis was made by accelerating voltage scanning. Quantification of the esters was made by single reaction monitoring, using calibration curves measured in the presence of the corresponding matrix. The detection limit for a selected lanosterol ester was below 300 pg. using this technique, each individual lanosterol and dihydrolanosterol ester was detected and quantified in a sample of wool wax. Interference from dihydroagnosterol esters is very likely, but interference from sterol esters which do not have a 4-methyl group is unlikely since the corresponding metastable peak is of very low intensity.
mesh_terms: D000818:Animals; D005227:Fatty Acids / Q000032:analysis; D007810:Lanosterol / Q000031:analogs & derivatives* / Q000032:analysis*; D013058:Mass Spectrometry / Q000379:methods; D014885:Waxes / Q000032:analysis*; D014935:Wool / Q000032:analysis*
chemical_list: D005227:Fatty Acids; D014885:Waxes; D007810:Lanosterol; C015316:lanostenol