Journal of Research and Development
Open Access

Abstract

Quantitative analysis of 25 Hydroxy vitamin D by LC/MS-assay standardization surprises.

Eduard Rogatsky

vitamin D deficiency is a widespread clinical problem and has been associated with many adverse health outcomes. Analysis of Vitamin D2 (ergocalciferol) and D3 (cholecalciferol) and their major metabolites 25(OH)D2 and 25(OH)D3 has become a high priority topic in clinical analysis. Currently a variety of LC/MS methods have been developed to support vitamin D analysis. These LC/MS methods utilize different transitions, ionization modes, sample preparation strategies, mobile phases and columns. In LC/MS analysis of 25 OH Vitamin D, dehydration (water loss) is the major side reaction. Comparing acetonitrile to methanol, which are typically used as mobile phases for LC separation, acetonitrile does not support hydrogen bond formation; therefore, proton-induced water elimination in-source becomes a major side-reaction, especially given the low pH of the mobile phase and positive mode electrospray and APCI ionization. MeOH, in contrast, supports hydrogen bond formation with the 25(OH)D2 and 25(OH)D3 hydroxyl groups.

Published Date: 2020-10-30;