Oligomer Analysis

[jan]

Hello,

I would like to get some information about oligomer analysis. How do one do quantitative analysis? Thank you in advance.

[Uwe Neue]

In order to give you a complete answer, one would need to know the polymer that you want to analyze and the molecular weight range.

You can use size exclusion chromatography using a packing with a very small pore size. Alternatively, you can run gradient chromatography. Once again the specific details would depend on the nature of your polymer. If the molecular weight range is not too large, you might even be able to use isocratic chromatography. Examples for all of these are available.

So what is the polymer, and what is the molecular weight range.

[jan]

Thanks, Uwe. What I am looking is Polyethylene Glycol (MW300). The mass range is 285-315.

[Mark Tracy]

If you want the shameless commercial pitch, search on my employer's website for "polyethylene glycol". To be fair, other vendors have published methods for this also.

Ethylene glycol oligomers this size can be done by reversed phase, if you find the right column (see commercial pitch). For a detector, you will want either refractive index or evaporative light scattering because they are (to a good first approx.) independent of molecular details.

[Uwe Neue]

This MW range of polyethylene glycol can be analyzed by several methods. I would use reversed-phase, but it is easier to find a SEC method. Multiple manufacturers offer solutions. My recommendation would be to call Waters. They most likely will recommend an Ultrahydrogel column.