[9] Stable isotope dilution mass spectrometry to assess vitamin a status

High-Performance Liquid Chromatography and Laser Desorption/Ionization Mass Spectrometry of Retinyl Esters

“…Electron impact mass spectra of retinoids show extensive fragmentation with a large number of uncharacteristic peaks . Chemical ionization of retinol often leads to quantitative dehydration .…”

“…Therefore reversed-phase high-performance liquid chromatography (HPLC) coupled with UV/visible detection is commonly used for isolation, separation, and identification of retinyl esters. − Limitations of HPLC separation and the similarity of absorption spectra, however, do not allow for unequivocal characterization. These disadvantages can be eliminated by employing mass spectrometry (MS), which provides both molecular weight information and characteristic fragment ion information helpful for structural elucidation. − …”

“…Various kinds of ionization techniques, including electron impact (EI), − positive or negative chemical ionization (PCI, NCI), , laser desorption/ionization (LDI), and electrospray (ESI) 16 mass spectrometry have been applied for analysis of underivatized retinol and related retinoids. Mass spectrometry of retinoids suffers particularly from their thermal instability.…”

Analysis of Cyclic and Acyclic Analogs of Retinol, Retinoic Acid, and Retinal by Laser Desorption Ionization-, Matrix-Assisted Laser Desorption Ionization–Mass Spectrometry, and UV/Vis Spectroscopy

“…Electron impact mass spectra of retinoids show extensive fragmentation with a large number of uncharacteristic peaks (15) and molecular weight information may be difficult to obtain (18). Chemical ionization of retinol and 3,4-didehydroretinol leads to quantitative dehydration as a result of ion-molecule collisions within the source (18). Similar results have also been obtained in attempts to perform HPLC-ESI-mass spectrometry of retinol (24).…”

“…Mass spectrometry of retinoids suffers particularly from the thermal lability of these compounds. Electron impact mass spectra of retinoids show extensive fragmentation with a large number of uncharacteristic peaks (15) and molecular weight information may be difficult to obtain (18). Chemical ionization of retinol and 3,4-didehydroretinol leads to quantitative dehydration as a result of ion-molecule collisions within the source (18).…”