Vitamin D Level Determination in Serum

Vitamin D₃ (cholecalciferol) is essential for the human body. Low levels of vitamin D₃ increase the risk of illness from a range of disorders. The serum level of vitamin D is monitored to exclude deficiency symptoms. As vitamin D products and nutritional supplements often contain vitamin D₃ and/or vitamin D₂ (ergocalciferol), usually the concentration of 25-hydroxy vitamin D₃ (25-OH-D₃, calcidiol) is determined. As vitamin D₂, D₃ and 25-OH-vitamin D₃ are structurally similar substances, the (U)HPLC separation is therefore very challenging. Often, special columns in combination with complex eluent mixtures have to be used. This application note demonstrates the determination of vitamin D using YMC-Triart C18 ExRS.