A Quantitative, Efficient Method for Analysis of 25-Hydroxy-Vitamin D3 and 25-Hydroxy-Vitamin D2 Using Automated Sample Preparation

A rapid, sensitive and reliable liquid chromatography–mass spectrometry (LC–MS) method was developed for the direct analysis of vitamin D metabolites in serum. The method enables the user to directly inject biological fluids into the LC–MS–MS system. The process reduces matrix effect and delivers fast and efficient quantitative results in a total time of five minutes. The intra-assay variability was less than 10.5% for both vitamin D₂ and vitamin D₃ and the assays have a dynamic range of 4 to 1000 ng/mL.