Guidelines for GPC in Eurolignin/ILI continued testing
Version 4, June 28th, 2006
The "guidelines" which I put last year on the ILI Internet Forum have been updated (see below). They have to be further discussed.
I assume the peak area of the UV signal is meant and not the "surface", but this is a minor point.
These methods rely on the following equation:
I agree to using toluene as an internal standard. However, the resolution of the system cannot be checked with toluene since the resolution is molar mass dependent. Therefore I recomment the use of toluene only for the determination of the plate number and asymetry. I would determine the resolution for each sample and specify a minimum number for the resolution, Rsp, or even better calculate the separation efficiency, T, as specified in the GPC standards ISO 13885-1 and DIN 55672-1. This ensures that there is enough effective separation (and not only potential resolution):
T = (V(Mx) - V(10Mx) [in ml]) / A(col) [in cm²] > 6,0
select Mx so that the peak maximum of the investigated sample is in the middle (center) between V(10Mx) and V(Mx)."