Hydrophilic polymer-modified polypropylene hollow fibers with controllable electroosmotic flow for capillary electrophoresis

Charged porous membrane structures for separation of biomolecules

“…The migration velocity of the electroosmotic flow estimated with benzyl alcohol has an average value of 13.4·10 -4 cm 2 /(V·s) at pH 9.5. This is in good agreement (order of magnitude) with values found for silica (8.0·10 -4 cm 2 /(V·s)) and values reported for polypropylene at the same pH by others: typically between 4.0-4.5·10 -4 cm 2 /(V·s) [47,53,63] having in mind the differences in measuring conditions, eg. the ionic strentgh.…”

“…Various polymeric capillaries were investigated in the CE mode for separation of both biomolecules and inorganic analytes: ethylene/vinylacetate (EVA) [50], nylon [50], poly(methyl methacrylate) (PMMA) [47,50], poly(butylene terephthalate) (PBTP) [48,50], poly(ether ether ketone) [46]. The biggest interest was, however, in polypropylene, used in both the untreated hydrophobic form [48,51], as well as hydrophilized by modification with cellulose [52], sulphonic acid, quaternary amine functionalities [53], dextran [49] or PMMA [54].…”

“…The high negative zeta-potential of polypropylene is believed to come from the adsorption of hydroxyl and e.g. phosphate ions from the buffer solution [53]. Only the surface of P84/SPEEK blend fiber and P84 fiber coated with SPEEK (SPEEK dissolved in the bore liquid) (Figure 8b) does not have isoelectric point and is ionized over wide pH range.…”

“…The noisy baseline might be due to the partial washing out of the BSA adsorbed during the previous runs. The following modifications of the hydrophobic PP surface either by dynamic coating or with chemically bonded layers in order to hydrophilize the PP for the separation of peptides and proteins were reported: with acrylamide [48], cellulose [52], sulphonic acid and quaternary amine groups [53], dextran [49], PMMA [47] [54]. This seems to be a good solution when capillary electrophoresis is performed, but in this work, the PP capillary is used only to seal the outer surface of the membrane (the stationary phase) and as a window for UV detection, and there is no large surface area of PP to be in contact with the sample zone.…”

Poly(tetrafluoroethylene) separation capillaries for capillary electrophoresis

“…Some other polymers have also been investigated. Polypropylene (PP) capillaries with a variety of hydrophilic surface modifications or poly(methyl methacrylate) (PMMA) have been utilised by Lee and co-workers, mainly for separations of proteins [24][25][26][27][28]. Ethylene vinyl acetate copolymer was used for the separation of porphyrins with photometric detection [29].…”