Methods for detecting vitamin D metabolites by mass spectrometry
AssigneeQuest Diagnostics Investments Incorporated
InventorsNigel Clarke, Brett Holmquist, Gloria Kwangja Lee, Richard E. Reitz
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Abstract
Provided are methods of detecting the presence or amount of a vitamin D metabolite in a sample using mass spectrometry. The methods generally comprise ionizing a vitamin D metabolite in a sample and detecting the amount of the ion to determine the presence or amount of the vitamin D metabolite in the sample. Also provided are methods to detect the presence or amount of two or more vitamin D metabolites in a single assay.
Claims31
A method for determining the presence or amount of 25-hydroxyvitamin D3 in a sample by tandem mass spectrometry, comprising:
- (a) generating a protonated and dehydrated precursor ion of 25-hydroxyvitamin D3 with a mass to charge ratio (m/z) of 383.16±0.5;
- (b) generating one or more fragment ions of said precursor ion;
- and
- (c) detecting the presence or amount of one or more of said ions generated in step (a) or (b) or both and relating the detected ions to the presence or amount of 25-hydroxyvitamin D3 in said sample.
The method of claim 1, 1,25-dihydroxyvitamin D2 in the sample.
A method for determining the presence or amount of two or more vitamin D metabolites in a sample in a single assay, said method comprising:
- (a) ionizing said two or more vitamin D metabolites, if present in said sample, to generate protonated and dehydrated precursor ions specific for each of said two or more vitamin D metabolites;
- (b) generating one or more fragment ions of each of said precursor ions;
- and
- (c) detecting the presence or amount of one or more of said ions generated in step (a) or (b) or both and relating the detected ions to the presence or amount of said two or more vitamin D metabolites in said sample;
- wherein said two or more vitamin D metabolites comprise 25-hydroxyvitamin D3 and 25-hydroxyvitamin D2;
- and
- wherein the precursor ion of 25-hydroxyvitamin D3 has a mass/charge ratio (m/z) of 383.16±0.5 and the precursor ion of 25-hydroxyvitamin D2 has a mass/charge ratio (m/z) of 395.30±0.5.
A method for determining the presence or amount of 25-hydroxyvitamin D2 in a sample by tandem mass spectrometry, comprising:
- (a) generating a protonated and dehydrated precursor ion of said 25-hydroxyvitamin D2 with a mass to charge ratio (m/z) of 395.30±0.5;
- (b) generating one or more fragment ions of said precursor ion;
- and
- (c) detecting the presence or amount of one or more of said ions generated in step (a) or (b) or both and relating the detected ions to the presence or amount of said 25-hydroxyvitamin D2 in said sample.
Dependencies are inferred from the claim text.