25-羟基维生素D2（麦角钙化醇或25-羟基钙化醇）是肝脏中发现的维生素D的代谢产物。 是人体循环中维生素D最常见的一种形式，对确定是否存在维生素D缺乏起着重要作用。25-羟基维生素D2（6,19,19-d3）是氘化的维生素D2氘取代了C-6和C -19的质子。 应用 25-羟基维生素D2（6,19,19-d3）可用作稳定同位素内标品，通过质谱分析特定生物样品的数据。 25-Hydroxyvitamin D2(ergocalciferol or 25-hydroxycalciferol) is a metabolite of vitamin D found in the liver. It is one of the most common forms of vitamin D circulating in the body and plays an important role in determining vitamin D deficiency.25-Hydroxyvitamin D2(6,19,19-d3) is a deuterated vitamin D2wherein C-6 and C-19 protons are replaced by deuterium.25-Hydroxyvitamin D2(6,19,19-d3) can be used as a stable isotope internal standard for data interpretation in specific biological samples by mass spectrometry.