An alternative route to dye–polymer complexation study using asymmetrical flow field-flow fractionation

The goal of the present work is to apply the versatile asymmetrical flow field-flow fractionation (AF4) coupled to UV and light scattering detection for the characterization of hyperbranched poly(ethylene imine) decorated with maltose shell (PEI-Mal) and the polar dye Rose Bengal (RB) in respect to their complexation behaviour. The quantitative determination of the non-complexed dye was carried out using the ultra-filtration effect of AF4 during the focussing phase, whereas the non-bound RB is filtrated and transported out of the channel while the complex of RB and PEI-Mal remains inside. A calibration with UV detector (550 nm) was established and different parameters (e.g. membrane material, molecular weight cut-off and stability of both, pure RB and RB@PEI-Mal complexes in solution) were investigated and verified. Successful reproducibility tests were performed. First complexation studies with the developed method were applied successfully with different mixture compositions of RB and PEI-Mal.