Simultaneous determination of vitamin D metabolites 25(OH)D

Although measurement of 25(OH)DSamples were purified from 250 µL human plasma. Chromatography was performed on an analytical column, under gradient conditions using a mobile phase consisting of methanol-lithium acetate. The mass detector was operated in positive multiple reaction monitoring mode. The established method was validated according to the guidance issued by ICH and FDA. Furthermore, a clinical study was performed using this method to detect the plasma concentrations of 1α,25(OH)The method was acceptably linear over the concentration ranges of 20-1200 pg/mL for 1α,25(OH)