Analysis of deuterated analogs of vitamin A by electron impact and chemical ionization modes in gas chromatography coupled to mass spectrometry.
To evaluate the total body reserves of vitamin A in humans, deuterated forms of vitamin A are potentially useful probes. In the present investigation, we have selected anhydroretinol as a useful indicator of retinol isolated from plasma during GC/MS analysis because of its relatively high volatility, its formation from retinol in good yield directly on GC columns, and the improbability of deuterium loss or exchange during its formation. The major drawback in its use is the extensive isomerization to cis-isomers which occurred on GC columns even under mild conditions of analysis. Favorable conditions for the GC/MS assay of anhydroretinol in the EI mode were defined. The mass spectral response is linear with the amount of retinol injected from 10 to 400 ng, and the observed sensitivity is adequate for the measurement of retinol in 1 ml of plasma. By using isobutane or methane, chemical ionization mass spectra of anhydroretinol and retinaldehyde are reported for the first time. Although both gave the expected [M + H]+ molecular ion, analysis of anhydroretinol in the EI mode was a more appropriate and sensitive measure of retinol under our assay conditions.
D000818:Animals; D003903:Deuterium / Q000032:analysis; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D007536:Isomerism; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012172:Retinaldehyde / Q000032:analysis; D014801:Vitamin A / Q000031:analogs & derivatives* / Q000032:analysis
D014801:Vitamin A; C031469:anhydrovitamin A; D003903:Deuterium; D012172:Retinaldehyde