Patent ID: 8076157

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 the sample to 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD) under conditions sufficient to generate one or more PTAD-vitamin D metabolite derivatives; (ii) ionizing one or more PTAD-vitamin D metabolite derivatives in the sample to generate one or more ions detectable by mass spectrometry, wherein said ionizing comprises volatilizing said one or more PTAD-vitamin D metabolite derivatives by laser diode thermal desorption; (iii) determining the amount of one or more of the PTAD-vitamin D metabolite derivative ions by mass spectrometry; and (v) relating the amount of PTAD-vitamin D metabolite derivative ions determined in step (iv) to the amount of a vitamin D metabolite in the sample; wherein said one or more vitamin D metabolite derivatives are selected from the group consisting of 25-hydroxyvitamin D 2 (25OHD 2 ), 25-hydroxyvitamin D 3 (25OHD 3 ), 1α,25-dihydroxyvitamin D 2 (1α,25(OH) 2 D 2 ), and 1α,25-dihydroxyvitamin D 3 (1α,25(OH) 2 D 3 ).