Analysis of vitamin D3, 25-hydroxyvitamin D3, and 7-DHC contents in egg yolk
Pooled egg yolk samples (of three yolks each) of each group were used for the
analysis of vitamin D metabolites. Commercial eggs were analyzed individually.
Vitamin D3, 25-hydroxyvitamin D3 (25[OH]D3) and 7-DHC were determined by
liquid chromatography-tandem mass spectrometry, as described previously [2].