To calculate the polymer conversion rate by GPC,

Assumptions:

a) If the solubility of the target polymer is good enough in THF/solvent,

b) and if the RI/UV absorption area is proportional to that of the sample weights detected (usually, the deviation should be acceptable)

1. you need the accurate sample weight of each sample/solvent used,

2. normalize the GPC graph by sample weight, 

3. overlay the normalized graphs,

4.the conversion should be dependent to the normalized surface areas of each curve,

5.please refer to “Kinetics and Mechanism of Emulsifier-Free Emulsion Polymerization: Styrene/Hydrophilic Comonomer (Acrylamide) System,” S.-A. Chen, S.-T. Lee, Macromolecules, 24, 3340-3351 (1991).

You can do it in many ways you can also do it with NMR. but the problem is if the molecular weight is increasing more than 20,000 it is difficult to do with IR, UV and NMR.