Contactless conductivity detection of selected organic ions in on-chip electrophoresis.
The detection of underivatized anionic sulfonates, carboxylates, amino acids, sugars, and artificial sweeteners, and of cationic dopamine, ephedrine, and metanephrine in microfabricated electrophoresis devices is demonstrated. This was achieved by high-voltage contactless conductivity measurements with external electrodes. Poly(methyl methacrylate) chips with thin covers to enable sensitive contactless detection were used for most determinations but glass microchips had to be employed for amino acids and sugars. The plastic chips were found not be stable in the alkaline media required to render those two classes of species in the ionic form amenable for separation and detection. The reproducibility of peak area measurements was about 1% or better and the detection limits ranged between 1 and 30 microM for the different compounds examined.
Department of Chemistry, The University of Basel, Spitalgasse 51, CH-4004 Basel, Switzerland.
Jatisai
J
Tanyanyiwa
Eva M
EM
Abad-Villar
Peter C
PC
Hauser
D000476:Alkanesulfonates / Q000032:analysis / Q000737:chemistry; D000596:Amino Acids / Q000032:analysis / Q000737:chemistry; D000838:Anions / Q000032:analysis* / Q000737:chemistry; D002264:Carboxylic Acids / Q000032:analysis / Q000737:chemistry; D002412:Cations / Q000032:analysis* / Q000737:chemistry; D004553:Electric Conductivity; D004566:Electrodes; D019075:Electrophoresis, Capillary / Q000379:methods*; D009930:Organic Chemicals / Q000737:chemistry*; D004364:Pharmaceutical Preparations / Q000032:analysis / Q000737:chemistry; D013549:Sweetening Agents / Q000032:analysis / Q000737:chemistry
D000476:Alkanesulfonates; D000596:Amino Acids; D000838:Anions; D002264:Carboxylic Acids; D002412:Cations; D009930:Organic Chemicals; D004364:Pharmaceutical Preparations; D013549:Sweetening Agents