By xiaolinwei on Tuesday, August 19, 2003 - 10:51 am:
we were trying to separate the mixtures of polymers by using the UltraHydrogel GPC column.The detector is the VWD(Varient wavelength detector). On the first several tries, we found several negative peaks and the intensity is very low, only several mAu. we were also trying to increase the concentration of the polymer, the spectrum doesn't improve. Does anyone have the experienxe for GPC? Please give me some recommendation for the next step. Thanks!
By Anonymous on Thursday, August 21, 2003 - 03:34 pm:
What is your mobile phase? What wavelength are you using?
By xiaolinwei on Friday, August 22, 2003 - 02:02 pm:
Anonymous, Thnaks for asking!
The mobile phase is 0.1N NaNO3 aqueous solution and the wavelength is 210nm.
By Jan Poskrobko on Sunday, August 24, 2003 - 10:50 pm:
First think about two possibilities:
1. Eluent is not enough strong to elute your polymer from column: add 20% ACN or MeOH to eluent.
2. Your polymer does not absorb at 210nm: change detector to refractive index detector.
By Chris Pohl on Friday, August 29, 2003 - 09:35 am:
Xiaolinwei,
Your problem is caused by the absorbance of your eluent at that wavelength. I assume you have a good reason for using an electrolyte in your eluent but you can't expect to get reasonable detection sensitivity when operating with a high absorbance background eluent such as the one you describe. You would be better off replacing it with a UV transparent eluent such as sodium methanesulfonate.