By Mary L. on Monday, January 26, 2004 - 12:53 am:
Could anyone tell me how to make polystyrene calibration standards for HPSEC (TSKG3000SW) so that they dissolve in 0.01 M sodium acetate, which is the mobile phase???? These are the things that nobody tells in the materials&methods...
By Chris Pohl on Monday, January 26, 2004 - 02:29 pm:
You're not going to get polystyrene to dissolve in an aqueous mobile phase. Forget about it, it can't be done. You will have to shift to water-soluble calibration standards. I did a quick check of the Polysciences catalog and the only neutral polymer standards available with narrow molecular weight distribution are polyethylene glycol standards but the highest molecular weight available in this series is 20,000. You can get polyacrylamide standards with molecular weight up to 9 million but the molecular weight distribution isn't all that great. You can also get polystyrene sulfonic acid standards with narrow molecular weight distribution up to 1.1 million, but calibration with a strong electrolyte polymer is a completely different can of worms, so I would advise against it.
By Anonymous on Wednesday, February 11, 2004 - 08:55 am:
I agree with Chris.
Some supplementary information:
Standards for aqueous SEC you can find e.g. at
ampolymer.com polymerlabs.com polymer.de etc..
I prefer as polystyrene analogues in aqu. SEC the pullulanes which are neutral with narrow distribution.
But be aware that aqu. SEC isn't that simple as THF-SEC.
PETER