Patent ID: 7977117

Claim:
A method for determining the amount of one or more vitamin D metabolites in a sample by mass spectrometry, the method comprising the steps of: (i) subjecting one or more 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD)-derivatized vitamin D metabolites in the sample to a turbulent flow liquid chromatography (TFLC) column and an analytical column; (ii) subjecting one or more PTAD-derivatized vitamin D metabolites in the sample to an ionization source to generate one or more ions detectable by mass spectrometry; (iii) determining the amount of one or more of the PTAD-derivatized vitamin D metabolite ions by mass spectrometry; and (iv) relating the amount of PTAD-derivatized vitamin D metabolite ions determined in step (iii) to the amount of a vitamin D metabolite in the sample, wherein the sample is subjected to PTAD under conditions sufficient to generate one or more PTAD-derivatized vitamin D metabolites prior to step (i).