Chromatography Forum

Can anyone tell me the condition and mobile phase for Vit C Tablets using C18 column (Waters Symmetry) and PDA detector?


Thank you very much!

Have you tried a literature search or contacting the vendors for application notes?

Vitamin C is so hydrophilic that it elutes in plain phosphate buffer at pH 3.0 +/- 0.5. The optimum pH depends on the sample matrix and interferences that you want to avoid. The Symmetry column is probably not the best option; a polar-embedded column is the better option. UV detection at 246; the spectrum is rather distinctive. Do you need to distinguish iso-ascorbic? If so, you need a long column.

Here is a nice alternative using mixed mode approach:

http://www.sielc.com/compound_149.html

You can achieve reasonable retention (5-15 min on 150 mm column) by playing with mobile phase pH and ion strength.

Contact me if you have questions

Vlad

If you want to analyze ascorbic acid without adding ion pairing reagents,
you can try using a silica column. This separation was done on
our Unison UK-Silica column:

http://www.imtakt.com/TecInfo/TI154E.pdf