Methods for detecting vitamin d metabolites by mass spectrometry
AssigneeQuest Diagnostics Investments Incorporated
InventorsNigel J. Clarke, Brett Holmquist, Gloria Kwang-Ja 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 directed to 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.
Claims8
A method for determining the amount of 25-hydroxyvitamin D3 or 25-hydroxyvitamin D2 in a sample by tandem mass spectrometry, comprising:
- (a) purifying a sample by liquid chromatography;
- (b) generating a protonated and dehydrated precursor ion of said 25-hydroxyvitamin D3 or 25-hydroxyvitamin D2 by atmospheric pressure chemical ionization (APCI);
- (c) generating one or more fragment ions of said precursor ion;
- and
- (d) determining the amount of one or more of said fragment ions generated in step (c);
- and
- (e) determining the amount of 25-hydroxyvitamin D3 or 25-hydroxyvitamin D2 in said sample from the amount of one or more of said fragment ions.
A method for determining the amount of 25-hydroxyvitamin D3 and 25-hydroxyvitamin D2 in a sample in a single assay, said method comprising:
- (a) purifying a sample by liquid chromatography;
- (b) ionizing by atmospheric pressure chemical ionization (APCI) said 25-hydroxyvitamin D3 and 25-hydroxyvitamin D2 to generate protonated and dehydrated precursor ions specific for each of said 25-hydroxyvitamin D3 and 25-hydroxyvitamin D2;
- (c) generating one or more fragment ions of each of said precursor ions;
- and
- (d) determining the amount of one or more of said fragment ions generated in step (c);
- and
- (e) determining the amount of 25-hydroxyvitamin D3 and 25-hydroxyvitamin D2 in said sample from the amount of one or more of said fragment ions.
Dependencies are inferred from the claim text.