Many problems encountered executing HPLC methods are a result of decisions made during early method development. This article discusses one critical variable in method development, the choice of stationary phase chemistry.
Vitamin D deficiency has become a topic of interest in recent publications (1–3). Vitamin D is present in two forms, Vitamin D3 and Vitamin D2. D3 is produced after ultraviolet light-stimulated conversion of 7-dehydrocholesterol in the skin (3).