Chromatography Forum

How can I separate polyols in ethylene glycol or propylene glycol using HPLC?

Do you need to see composition or just need to estimate the total amount of polyglycols? What are detection techniques available for you? What is sample matrix and concentrations?

I am specifically looking for glycerol and sorbitol, and I need to find their concentrations. I am currently using UV-VIS detector, but refractive index is also available. What do you mean by sample matrix?

Is the sample matrix pure Ethylene Glycol and Propylene Glycol?

What are the expected concentrations of Glycerol and Sorbitol? Or do you have a lower limit that you need to be able to detect?

I am specifically looking for glycerol and sorbitol, and I need to find their concentrations. I am currently using UV-VIS detector, but refractive index is also available. What do you mean by sample matrix?

What ever you see in UV with this method might not be your targets as they are not UV active, any impurity which has much better UV will mislead you. I would advice to stay away from UV unless you want to do derivatization.
RI might be a better choice, but I would suggest using Corona CAD or ELSD (at low temperature set up for glycerol.

You can use this approach to analyze your mixture:
https://twitter.com/HelixChrom/status/1 ... 80/photo/1
https://helixchrom.com/compounds/sorbitol/

Glycerol should retain too with this conditions. It is an isocratic method so you can use RI with no issue

Contact me if you have a questions

One approach is described in Wang et al., Journal of Chromatography A, 1514 (2017) 95–102. Another approach is to use a Cogent Amide column with acetonitrile/water mobile phase. For clean or cleaned-up (SPE) samples you can use UV at 195 nm or RI detection. John