67C-25 |
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L. YE1, A. Szulczewska-Remi2, and R. R. Eitenmiller1. (1) Dept. of Food Science & Technology, Univ. of Georgia, Food Science Bldg., Athens, GA 30602-7610, (2) Dept. of Food Science & Technology, August Cieszkowski Agricultural Univ. of Poznan, Poznan, Poland Analysis of vitamin E in various spices, herbs and highly spiced processed foods has been problematic due to the presence of late-eluting large peaks with strong fluorescence in extracts of saponification digests. Such interfering peaks complicate interpretation of chromatograms, extensively increase run-time and increase solvent usage. Due to the inability to predict elution times of the interfering peaks, subsequent chromatographic runs are often ruined due to the interferences from the previous injection overlapping areas of the chromatogram containing analytes to be quantified. To develop a simple and rapid sample preparation procedure for the LC analysis of vitamin E in spices, herbs and highly-spiced foods. Following saponification, the digest was extracted 2 x with 25 mL hexane/ethyl acetate (90:10) containing 0.01% BHT. The combined extracts were diluted to 50 mL with hexane. Two mL of the extract were added to a SPE silica column previously conditioned with 5 mL of acetone followed by 3 mL of 10% ethyl acetate in hexane. The SPE column was eluted with 1 mL of 20% ethyl acetate in hexane followed by two 0.5 mL portions of 20% ethyl acetate in hexane. The combined eluates were evaporated to dryness with N2 and redissolved in hexane, filtered and injected. The SPE treatment completely removes fluorescent interferences from saponification digests of spices and herbs. Accuracy reported as % recovery (mean ± S.D.) of spiked tocopherols were 99.8 ± 0.95, 101.6 ± 1.83, 100.9 ± 0.83 and 101.4 ± 3.73 for a -, b -, g - and d -tocopherol, respectively. Precision studies completed on black pepper gave % CV values of 4.47 and 7.42 (intra-day) and 1.56 and 5.31 (inter-day) for a - and g -tocopherol, respectively. The method is simple, quick and greatly shortens sample running time. It is an easily applied clean-up step which allows vitamin E assay of spices and herbs with high accuracy and precision.
Session 67C, Food Chemistry: Food analysis, irradiation and toxicology
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