The analysis of synthetic organic, neutral polymers using nonaqueous capillary gel electrophoresis (NACGE)

We describe, in this paper, efforts to develop an optimized, replaceable, polyethylene oxide [PEO, aka polyethylene glycol (PEG)] gel in nonaqueous CGE (NACGE) for the analysis and characterization [molecular weights (MWs)] of a series of synthetic, organic polymers, mainly polystyrenes (PS) and polymethylmethacrylates (PMMA). The approach utilizes a novel combination of organic solvent run buffers, with varying levels of water and a hydrophobic cationic monomer, to induce electrophoretic flow or forces (EPF) in the organic polymers. The gel is fixed in place, using a coated capillary to prevent electroosmotic flow (EOF), so that only the analyte polymers move through the gel with time and applied voltage. Depending on the nature of the organic gel in the capillary and the buffer additives, polymers of known MWs can be made to migrate through the capillary with time, generating a standard MW vs. migration time calibration plot, analogous to what is derived for SEC analysis of the very same polymers. Though the range of this linearity appears rather limited, perhaps because of the nature of the PEO gels available, it is still possible to determine relative MWs for a series of known, standard PS and PMMA polymers, with reasonable accuracy and precision of such measurements.