A liquid chromatography-mass spectrometry method for the quantification of bioavailability and bioconversion of β-carotene to retinol in humans.

A method based on high-performance liquid chromatography−atmospheric pressure chemical ionization mass spectrometry (APCI LC−MS) was developed for the quantification of the bioavailability of retinyl palmitate and β-carotene and the bioconversion of β-carotene to retinol in humans. Following oral administration of [8,9,10,11,12,13,14,15,19,20-13C10]-retinyl palmitate and [12,13,14,15,20,12‘,13‘,14‘,15‘,20‘-13C10]-β-carotene at physiological doses to children between 8 and 11 years of age, blood samples were drawn and serum was prepared. Retinol and β-carotene were extracted from 0.2- and 1.0-mL serum samples, respectively, and analyzed using reversed-phase HPLC with a C30 column interfaced to an APCI mass spectrometer. Unlike other LC−MS assays for carotenoids, no additional purification steps were necessary, nor was any derivatization of retinol or β-carotene required. APCI LC−MS showed a linear detector response for β-carotene over 4 orders of magnitude. Using selected ion monitoring to record the eluti...