[natas]

Hello everybody,

For several weeks now I am working on a project for school and for my boss (I'm also working in a factory where they are producing polystyrene).
At first my project was: make a GPEC method for measuring polystyrene so we might see difference between our material and material of the other factories.
Last week I had a nice chromatogram from the literature and he said: that's what I want to see! So the project changed into: find out more about the oliogomers of polystyrene. The chromatogram from the literature was made with an ELS-detector and for now I only have an UV detector. So I have to wait for it and do some other trials.

What I would like to know: Is there anybody who can tell me more about GPEC in practice?
And is there someone who can tell me more about measuring oligomers in practice?

Thank you!

[chiralic]

Question:
Are you using Normal-phase gradient polymer elution chromatography (NP-GPEC) or
reversed-phase gradient polymer elution chromatography (RP-GPEC)?

What Column are you using?

[natas]

I'm using a C18 (Nova Pak column) with RP-HPLC

[chiralic]

With UV detector you'll have some trouble with THF gradient, that is the reason "why" is better use evaporative light scattering (ELS) detector.

Do you know these Thesis:

• Philipsen, H. J. A. Mechanisms of Gradient Polymer Elution Chromatography and its Application to (Co)polyesters Ph.D. Thesis, Technische Universiteit Eindhoven, Eindhoven, 1998
• P.J.C.H. Cools. Characterization of Copolymers by Gradient Polymer Elution Chromatography, by , PhD. Thesis, Eindhoven University of Technology,1999

Also, I recommend you read this paper:
Cools P.J.C.H.; Maesen F.; Klumperman B.1; van Herk A.M.; German A.L.
Determination of the chemical composition distribution of copolymers of styrene and butadiene by gradient polymer elution chromatography.
Journal of Chromatography A, Volume 736, Number 1, 7 June 1996, pp. 125-130

[natas]

Like u said, I already have read a lot about the ELSD. And maybe we will buy this but that's not for sure. And for now I have only the UV detector to measure with.

The point is: now my boss wants me to see if I can measure the oligomers of polystyrene. And I think that will work with ELSD.

The papers you gave do ring a bel to me. But most of these are about copolymers and I have only pure polystyrene of which we want to see the oligomers. I started with a book: GPEC by W. Staal
Now I'm working with the paper: Y. Burn, Gradient separation of polymers at critical point of adsorption
Also I have: Phillipsen, H.J.A. Determination of chemical composition distributions in synthetic polymers (I got this paper from H. Claessens, who also has written a lot about polymers)

Thank you for the papers, I will search for them immideately!

[chiralic]

Baseline drift, which would be observed with UV detector due to changes in absorbance of the eluent gradient

[chiralic]

are you checked this?

Normal phase gradient polymer elution chromatography of polyester resins
http://www.springerlink.com/content/r8t313r815115881/

[natas]

I'm checking it now...I've read so much already that sometimes I don't know what I am doing
Also I can only read these papers at school, otherwise I can't get further than the summary.

Also, I'm not interested in copolymers  (like your link) only the oligomers of polystyrene

The baseline drift I have seen. Maybe it will help if I run a blanc so I can pull this off the sample chromatogram...

Do you work with this? Because you can so quickly find out all the papers...!?

[chiralic]

I found this:
Molar mass effects in reversed-phase gradient polymer-elution chromatography of oligomers
http://www.springerlink.com/content/nv31p43174581020/

Abstract (extract)
The dependence on molar mass of the retention of oligomers in reversed-phase gradient polymer-elution chromatography (RP GPEC) has been investigated. To this end a variety of oligomer series, including polystyrene (PS) and amorphous polyesters (PE) were chromatographed using different non-solvent-solvent (NS-S) mobile phases and at different temperatures.

[natas]

I just found the same paper

I also have: Gradient separation of polymers at critical point of adsorption (by Brun and Alden) This is more about ELSD but I'm measuring with the same conditions but with the UV. Now I see differences between ACN and MeOH as non-solvent. So with this information I can also choose for the right eluenses.

Thank you for all your research!! Is it just for me or do you want to know more about it?
Are you also working with it?

I'm al little bit curious because I want to find people who know more about it than me, or work with something like this...

[chiralic]

I'm Chemical Engineering and Instrumental Analytical Chemist and I worked to Venezuelan Petroleum Institute (INTEVEP). I always have worked with Chromatography (in all mode) and Capillary Electrophoresis . In this moment, I'm adviser to Scientific Police as Forensic Chemist in my country (like a CSI Officer).

I like lend a hand to the people who wants and need knowledge...My private email is: chiralic@gmail.com

Regards,

Chiralic

[natas]

Well, thank you for all your information so far!
If I need more I will send you an email or I will ask it here...

I'm Analytical Chemist at a factory (in the Netherlands, Synbra Technology) where we produce polystyrene. I work there for about 3 years now and hope I will graduate this your for...well, I really don't know how this is called in english 

Nice job you have now...That's something I also wanted to do but the closest one is too far for me
Where I work now is not really what I want to do so I'm still searching...

Thank you for your research!!