The present invention relates generally to methods for one-step
purification of organic polymers using tangential flow filtration. In one
embodiment, the present invention relates to methods for size
fractionation of heterogeneous organic polymers, such as poly(ethylene
glycol) derivatives, using tangential flow filtration. The present
invention also relates to purification of low molecular weight
monofunctional organic polymer derivatives produced by procedures in
which high molecular weight bifunctional poly(ethylene glycol) impurities
are removed. The present invention further relates to purification of
high molecular weight branched polymer products from low molecular weight
starting materials.