ADAPTATION OF A CAROTENOID PROCEDURE TO ANALYZE CAROTENOIDS, RETINOL, AND ALPHA-TOCOPHEROL SIMULTANEOUSLY

An isocratic procedure for carotenoids (Nelis and De Leenheer, 1983) was extended by monitoring at an extra wavelength (280 nm) and use of tocopheryl acetate as internal standard to include retinol (vitamin A) and alpha-tocopherol (vitamin E) with carotenoid analysis in a single chromatographic run. Peaks were validated by retention times, spiked test and signal ratio (313 nm/280 nm). Within-run CVs (n=10) were 4.7% and 2.9% and between-run CVs (n=9) were 7.3% and 5.1% for vitamins A and E respectively. Linearities were up to at least 1.8 ug/mL (vitamin A) and 46.5 ug/mL (vitamin E). Vitamins A and E of twenty serum samples were analyzed by this procedure (I) and a reference procedure (II) and their correlations were 0.8484 and 0.9919 respectively. Linear regressions were I=II(0.806)+0.225 ug/mL (vitamin A) and I=II(0.974)+0.52 ug/mL (vitamin E) were 118% and 111% for vitamins A and E respectively. This isocratic procedure can analyze at least five carotenoids and vitamins A and E in serum simultaneously. It is simple and economic in time and reagents. Chromatographic run is within 20 minutes. Only a double channel absorbance detector is needed, without the use of programmable absorbance detector, diode-array detector or gradient elution. It will be a useful tool to study the role of carotenoids, vitamins A and E in human chronic diseases such as coronary heart disease and cancer.