Electroosmotic flow-balanced isotachophoretic stacking with continuous electrokinetic injection for the concentration of anions in high conductivity samples.
An EOF counter-balanced ITP boundary has been used to stack anions from high conductivity samples during continuous electrokinetic injection of the sample. In a polystyrenesulfonate/poly(diallyldimethylammonium chloride) polyelectrolyte coated capillary, the time at which the ITP boundary exited the capillary could be prolonged by balancing the movement of the boundary with the EOF. Using a bis-tris-propane electrolyte, the ITP boundary was removed from the capillary within 7min, while when using triethanolamine the ITP boundary was still at 30% of the capillary after 2h of injection. Using these systems, the sensitivity of a mixture of simple organic acids in 100mM Cl(-) was improved by 700-800-fold using bis-tris-propane with a whole-capillary injection of the sample and 5min of electrokinetic injection at +28kV, and 1100-1300-fold using triethanolamine and 60min of electrokinetic injection under the same conditions. The potential of the method to be applicable to high conductivity samples was demonstrated by stacking a whole capillary filled with urine spiked with naphthalenedisulfonic acid, with limits of detection 450 times lower than those achievable with a normal hydrodynamic injection.
Breadmore
Michael C
MC
Australian Centre for Research on Separation Science (ACROSS), School of Chemistry, University of Tasmania, Hobart, Tasmania, Australia. mcb@utas.edu.au
D000143:Acids / Q000737:chemistry; D000838:Anions / Q000652:urine*; D003198:Computer Simulation; D004553:Electric Conductivity; D004573:Electrolytes / Q000737:chemistry; D053841:Electroosmosis; D019075:Electrophoresis, Capillary / Q000379:methods*; D004983:Ethanolamines / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D012680:Sensitivity and Specificity; D014325:Tromethamine / Q000031:analogs & derivatives / Q000737:chemistry
D000143:Acids; D000838:Anions; D004573:Electrolytes; D004983:Ethanolamines; D014325:Tromethamine; C034249:1,3-bis(tris(hydroxymethyl)methylamino)propane; C009546:triethanolamine