Chromatography Forum

Hello,

We have two columns in use for two carbohydratess analysis. One column is a Varian Metacarb 87H Plus and the other is Aminex 87CH from BioRad. the Varian column works with 0.1NH2SO4 at 0.6 ml/min with a temp of 60C. The BioRad column's mobile phase is water and temp. 80C. Flow is 0.6 ml/min.

The que4stion is what happens when switchin from Varian to BioRad. Small cuantities of 0.5N H2SO4 will go inside of the BioRad columns. Somebody knows what happens here?

Thank you for your answer.

Regards,


Analisis

The BioRad column contains a cation exchange resin in the Calcium form; any sulfate injected will combine with the Ca++ to form CaSO4. The common name for CaSO4 is "plaster of paris".

Make sure you thoroughly flush the system with water between column changes!

Thank you for your answer. We have had inversion in the sugars in the Biorad column. I don't understand what really is a inversion, but I see that the sucrose peak gets smaller and the peaks of fructose and glucose grew . when we check the areas the sum is still the same but the proportion of the sugars have changed. Where can I read about these?

Thank you and I wish you a very prosperous new year.

Regards,

Analisis

Analysis,

are you saying that the same sample, e.g. solution from one vial, gave different distribution among the three sugars though both column have good separation? In other words, decomposition/hydrolysis happens drastically more in one column than the other. if so, the combination of pH, temperature, solvents, and trace metal as catalyst provide an optimal hydrolysis condition.

If not, I bet the hydrolysis happens in prep and/or storage.