抄録
Eggs are a major source of vitamin D, and contain the metabolized forms such as 25-hydroxyvitamin D3 (25-OH-D3). In this study, we developed a novel analysis method for determining 25-OH-D3 in egg by HPLC. After extraction with a hexane-ethylacetate mixture, the crude extract was subjected to preparative normal phase LC using an aminopropyl column. 25-OH-D3 content in the fraction was determined by reversed phase LC using an ODS column. The method validation results confirmed that the method had good linearity (r > 0.999), accuracy (98% of recovery) and precision (4.8% of RSDr). The LOD and the LOQ were determined to be 0.04 and 0.13 μg/100 g, respectively. Market research undertaken in Japan clarified the different characteristics of 25-OH-D3 and vitamin D3 contents in fortified eggs. There were no significant differences in 25-OH-D3 content between normal and fortified eggs, although significant differences in vitamin D3 levels were observed.
