Abstract:

An analytical method for the determination of vitamin A (VA) reserved in human liver by stable isotope dilution technique and high performance liquid chromatography-gas chromatography/negative ion chemical ionization/mass spectrometry (HPLC-GC/NCI/MS) was developed. Before the test, deuterium labelled retinol acetate (²H₈-RAC) (1 mg) was ingested by the volunteers. After 21 days, the blood samples were collected and the serum was separated. The VA was extracted by n-hexane and purified by HPLC. Then the purified VA was dried under nitrogen for further derivatization. The derivative was finally detected by GC/NCI/MS. The concentration of the VA in the liver was calculated by using the formula of Furr-Olson. Under the optimized conditions, more than 85% of the VA in the serum samples could be collected, purified and detected. The detection precision (relative standard deviation, RSD, n=6) was less than 10% and the quantitative limit reached 26.4 μ g/L, which met the marked and unmarked VA detection requirements. Compared with the current domestic VA evaluation method, this method can more objectively reflect human VA nutrition level. When this determination technology combines with VA intervention experiment, it could evaluate a dietary intake level of VA to maintain a stability reserve level. At the same time, it also plays an important role in the research on biological conversion efficiency of carotene ingestion.

Key words: gas chromatography/negative ion mode of chemical ionization/mass spectrometry (GC/NCI/MS), high performance liquid chromatography (HPLC), liver reserve, stable isotope dilution, vitamin A (VA)