Detection of vitamins A and E by tandem mass spectrometry
View Patent ↗Methods are described for measuring the amount of one or more of vitamin A, α-tocopherol, and the combination of β-tocopherol and γ-tocopherol in a sample. More specifically, mass spectrometric methods are described for detecting and quantifying one or more of vitamin A, α-tocopherol, and the combination of β-tocopherol and γ-tocopherol in a sample.
1. A method for determining the amount of vitamin A in a sample by tandem mass spectrometry, said method comprising:
a. subjecting vitamin A from a sample to ionization under conditions suitable to produce one or more ions detectable by mass spectrometry; and
b. determining the amount of one or more of said ions by tandem mass spectrometry, wherein tandem mass spectrometry comprises fragmenting a vitamin A precursor ion having a mass to charge ratio of about 269.30±0.80 into one or more fragment ions comprising a fragment ion having a mass to charge ratio of about 105.00±0.80;
wherein the amount of the one or more fragment ions determined in step (b) is related to the amount of vitamin A in the sample.
2. The method of claim 1 wherein the sample is subjected to liquid chromatography (LC) prior to ionization.
3. The method of claim 2 , wherein said LC is reverse phase LC.
4. The method of claim 2 wherein said LC and said ionization are conducted with on-line processing.
5. The method of claim 1 wherein the sample is subjected to high performance liquid chromatography (HPLC) prior to ionization.
6. The method of claim 1 , wherein said ionization comprises ionization with an atmospheric chemical ionization (APCI) source.
7. The method of claim 1 , wherein the sample comprises a biological sample.
8. The method of claim 7 , wherein the biological sample is from a human patient suspected of having a deficiency or an excess of vitamin A.
9. The method of claim 1 , wherein the sample comprises serum or plasma.
10. The method of claim 1 , wherein tandem mass spectrometry is conducted by multiple reaction monitoring, precursor ion scanning, or product ion scanning.
11. The method of claim 1 further comprising determining the amount of one or more additional analytes simultaneously with the determination of the amount of vitamin A.
12. The method of claim 11 , wherein the one or more additional analytes comprises one or both of α-tocopherol and combined β-tocopherol and γ-tocopherol.
13. The method of claim 12 wherein the one or more additional analytes comprises α-tocopherol, and determining the amount of α-tocopherol comprises fragmenting an α-tocopherol precursor ion having a mass to charge ratio of about 430.47±0.80 into one or more fragment ions comprising a fragment ion having a mass to charge ratio of about 165.03±0.80.
14. The method of claim 12 wherein the one or more additional analytes comprises combined β-tocopherol and γ-tocopherol, and determining the amount of combined β-tocopherol and γ-tocopherol comprises fragmenting β-tocopherol and γ-tocopherol precursor ions having a mass to charge ratio of about 416.35±0.80 into one or more fragment ions comprising a fragment ion having a mass to charge ratio of about 151.00±0.80.
15. The method of claim 12 wherein the one or more additional analytes comprises α-tocopherol and combined β-tocopherol and γ-tocopherol.