Determination of vitamin D and retinoid activity in eggs by HPLC.

Reverse phase high performance liquid chromatography (HLPC) was used to estimate the vitamin D3 content of battery and free range eggs. At the same time another HPLC technique was used to estimate the retinol activity in the battery eggs derived from the separate determination of all-trans retinol, 13-cis retinol and retinaldehyde concentrations. There was some variation in both the vitamin D3 and retinol activity in eggs over the laying year but no significance could be drawn from this. Vitamin D3 levels in 12 monthly samples each of 120 battery eggs averaged 1.2 micrograms/100 g edible portion, while the levels in each of four quarterly samples of 36 free range eggs from the London and Newcastle areas averaged 1.4 and 0.8 micrograms/100 g respectively. These differences between battery and free range eggs were not statistically significant. The average retinol activity in four samples of 120 battery eggs was calculated to be 190 micrograms/100 g, and the components of this activity were identified as 132 micrograms all-trans retinol and 21 micrograms of retinaldehyde, as well as 53 micrograms 13-cis retinol which has not previously been reported in hens' eggs.