The Application Notebook
Separations of structurally similar compounds such as vitamin D2 and vitamin D3 are very challenging.
Vitamin D2 (ergocalciferol) and D3 (cholecalciferol) can be found in different foods including fatty fishes, meat, egg, and some mushrooms. Both compounds are (indirectly) involved in a number of biological functions in the body, including bone metabolism and enhancement of intestinal absorption of calcium, iron, magnesium, phosphate, and zinc. A regular intake of vitamin D therefore is essential.
Figure 1: Structures of vitamin D2 and vitamin D3.
Standard C18 columns are not able to fully separate the two vitamins. A very hydrophobic phase with a higher carbon coverage and therefore a greater density of C18 chains is required. The highly hydrophobic phase YMC-Triart C18 ExRS (carbon load 25%!) is able to separate these two.
Figure 2: Easy method transfer HPLC <-> UHPLC as a result of full scalability.
The isocratic high performance liquid chromatography (HPLC) method for vitamin D2 and D3 separation, using a 5 μm YMC-Triart C18 ExRS column, can easily be transferred to a ultrahigh-performance liquid chromatography (UHPLC) method using a 1.9 μm column, thereby reducing the analysis time by 50%. Furthermore, the resolution can be increased, resulting in a full baseline separation.
YMC-Triart C18 ExRS (5 µm, 8 nm), 150 × 3.0 mm
YMC-Triart C18 ExRS (1.9 µm, 8 nm),
75 × 2.1 mm
YMC Europe GmbH
Phone: +49 2064 4270
E-mail: info@ymc.de
Website: www.ymc.de
Understanding FDA Recommendations for N-Nitrosamine Impurity Levels
April 17th 2025We spoke with Josh Hoerner, general manager of Purisys, which specializes in a small volume custom synthesis and specialized controlled substance manufacturing, to gain his perspective on FDA’s recommendations for acceptable intake limits for N-nitrosamine impurities.