Simultaneous quantification of carotenoids and tocopherols in corn kernel extracts by HPLC

An isocratic high performance liquid chromatographic (HPLC) method with run times of less than 22 min has been developed for simultaneous analysis of carotenoids and tocopherols in corn. The reverse phase system utilizes a nonaqueous mobile phase in combination with a polymeric C-18 column coupled to a monomeric C-18 column to separate lutein, zeaxanthin, beta-cryptoxanthin, alpha-carotene, beta-carotene, and the alpha-, delta- and gamma- forms of tocopherol. The detector was a multi-channel UV-VIS. One channel was used to monitor carotenoid absorption at 450 nm while another monitored tocopherols at 290 nm.Retention times and spiked tests with known standards validated peak identification. Linear regressions of external standards generated coefficients of determination (R-2) that were in the ninety-ninth percentile for all compounds tested. Using the same samples, concentrations generated from our protocol and compared with results from other laboratories suggest that this procedure is relatively accurate.