Upgrade for 3-epi-25-OH-Vitamin D3/D2 - LC-MS/MS

The upgrade to MassChrom® 25-OH-vitamin D3/D2 analysis allows for the separation of 25-Hydroxycholecalciferol and 25-Hydroxyergocalciferol from their epimeric forms 3-epi-25-OH-vitamin D3 and 3-epi-25-OH-vitamin D2, hence allowing for separate quantification by LC MS/MS. Manual sample preparation is still simple and effective protein precipitation. As with the 25-OH-vitamin D3/D2 determination, the analytes are enriched with the aid of a trap column ONLINE and thus, interfering matrix components are isolated. Chromatographic separation and further purification of all analytes is then performed by a special high resolution analytical column connected to the trap column by a valve. The method features the use of APCI (atmospheric pressure chemical ionisation) and the isotopically labelled internal standards adjusted to the epimeric forms. Matrix effects (“ion suppression”) are minimised and the performance of the method is optimised. The 3PLUS1®  multilevel calibrators also include both epimeric forms of 25-OH-vitamin D3/D2 and ensure high performance of results.