Determination of chloride, sulfate and nitrate in drinking water by microchip electrophoresis

• Published in: Mikrochimica acta (1966) Vol. 177; no. 3-4; pp. 309 - 316
• Main Authors: Masár, Marián, Bomastyk, Benjamin, Bodor, Róbert, Horčičiak, Michal, Danč, Ladislav, Troška, Peter, Kuss, Heinz-Martin
• Format: Journal Article
• Language: English
• Published: Vienna Springer Vienna 01.06.2012; Springer
• Subjects: Analysis; Analytical Chemistry; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Chromatographic methods and physical methods associated with chromatography; Drinking water; Electric properties; Electrochemical methods; Electrolytes; Electrophoresis; Exact sciences and technology; Integrated circuits; Microengineering; Nanochemistry; Nanotechnology; Original Paper; Other chromatographic methods; Semiconductor chips; Sulfates; Microchip electrophoresis; Water analysis; Conductivity detection; Inorganic anions; Drinking water; Internal standard; Nitrates; Sulfates; Chemical enrichment; Chlorides; Electroosmosis; Detection limit; pH; Electrophoresis; Inorganic amnions; Time analysis; Quantitative analysis; Filtration; Sample; Use; Hydrodynamics; System on a chip; Isotachophoresis; Method; Treatment; Conductometry; Ionic strength; Reproducibility; Simultaneous measurement; Transfer; Propane
• ISSN: 0026-3672; 1436-5073
• DOI: 10.1007/s00604-012-0788-3

We report on a method for simultaneous determination of chloride, sulfate and nitrate in drinking water by microchip electrophoresis. By adjusting a pH value of 4.2 in the aspartate background electrolyte, and by applying separation mechanisms via the ionic strength effect (bis-tris propane) and association equilibria (N-dodecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate), a complete resolution of analytes from other co-migrating constituents is accomplished. In addition, isotachophoretic preconcentration of nitrate was implemented directly on the microchip. The ions were detected via conductivity measurements after injecting 900-nL samples. The limits of detection range from 40 to 120 μg L -1 . The method displays a high reproducibility of the migration velocities under suppressed hydrodynamic and electroosmotic flow and therefore allows for a precise quantitation of analytes. The total analysis time is <450 s, and the working range is up to 60 mg L -1 for chloride and sulfate, and of up to 20 mg L -1 for nitrate. Filtration and degassing are the only sample treatment steps prior to analysis. The use of an internal standard enabled an easy chip-to-chip transfer of the method. Figure Determination of Chloride, Sulfate and Nitrate in Water by Microchip Electrophoresis