Mass fragmentographic determination of cholecalciferol and 25-hydroxycholecalciferol in human serum

The serum extracts were purified by column-, thin layer- and high pressure liquid chromatography. Deuterated cholecalciferol and deuterated 25-hydroxycholecalciferol were used in internal standards. The quantitative analysis was performed using GC-mass fragmentography technique of TMS-ethers.