title: High-buffering capacity, hydrolytically stable, low-pI isoelectric membranes for isoelectric trapping separations.
abstract: Hydrolytically stable, low-pI isoelectric membranes have been synthesized from low-pI ampholytic components, poly(vinyl alcohol), and a bifunctional cross-linker, glycerol-1,3-diglycidyl ether. The low-pI ampholytic components used contain one amino group and at least two weakly acidic functional groups. The acidic functional groups are selected such that the pI value of the ampholytic component is determined by the pK(a) values of the acidic functional groups. When the concentration of the ampholytic component incorporated into the membrane is higher than a required minimum value, the pI of the membrane becomes independent of variations in the actual incorporation rate of the ampholytic compound. The new, low-pI isoelectric membranes have been successfully used as anodic membranes in isoelectric trapping separations with pH < 1.5 anolytes and replaced the hydrolytically less stable polyacrylamide-based isoelectric membranes. The new low-pI isoelectric membranes have excellent mechanical stability, low electric resistance, good buffering capacity, and long life time, even when used with as much as 50 W power and current densities as high as 33 mA/cm(2) during the isoelectric trapping separations.
authors.affiliation: Department of Chemistry, Texas A&M University, College Station, TX, USA.
authors.forename: Sanjiv
authors.initials: S
authors.lastname: Lalwani
authors.forename: Evan
authors.initials: E
authors.lastname: Shave
authors.forename: Gyula
authors.initials: G
authors.lastname: Vigh
mesh_terms: D002021:Buffers; D004852:Epoxy Compounds / Q000737:chemistry; D005995:Glyceryl Ethers / Q000737:chemistry; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007098:Imino Acids / Q000737:chemistry; D007525:Isoelectric Focusing / Q000379:methods*; D007526:Isoelectric Point; D008567:Membranes, Artificial; D011142:Polyvinyl Alcohol / Q000737:chemistry
chemical_list: D002021:Buffers; D004852:Epoxy Compounds; D005995:Glyceryl Ethers; D007098:Imino Acids; D008567:Membranes, Artificial; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; C058056:glycerol 1,3-diglycidyl ether; D011142:Polyvinyl Alcohol; C008109:iminodiacetic acid