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Application of an external contactless conductivity detector for the analysis of beverages by microchip capillary electrophoresis
Author(s) -
Kubáň Pavel,
Hauser Peter C.
Publication year - 2005
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.200500178
Subject(s) - capillary electrophoresis , chemistry , electrolyte , detection limit , thermal conductivity detector , conductivity , analytical chemistry (journal) , chromatography , stacking , electrophoresis , calibration curve , organic anion , inorganic chemistry , ion , gas chromatography , electrode , organic chemistry
Quantitative total ionic analysis of alcoholic and nonalcoholic beverages was performed by microchip capillary electrophoresis with external contactless conductivity detection. An electrolyte solution consisting of 10.5 m M histidine, 50 m M acetic acid, and 2 m M 18‐crown‐6 at pH 4.1 was used for the determination of NH 4 + , K + , Ca 2+ , Na + , and Mg 2+ . Fast analysis of Cl − , NO 3 − , and SO 4 2− was achieved in 20 m M 2‐( N ‐morpholino)ethanesulfonic acid /histidine electrolyte solution at pH 6.0 and the simultaneous separation of up to 12 inorganic and organic anions was performed in a solution containing 10 m M His and 7 m M glutamic acid at pH 5.75. Limits of detection ranged from 90 to 250 μg/L for inorganic cations and anions, and from 200 to 2000 μg/L for organic anions and phosphate. Calibration curves showed linear dependencies over one to two orders of magnitude when the stacking effect was minimized by injecting standard solutions prepared in background electrolyte solutions. Total analysis times of 35 and 90 s were achieved for the determination of 5 inorganic cations and for the simultaneous determination of 12 inorganic and organic anions, respectively, which represents a considerable reduction of analysis time compared to conventional separation methods used in food analysis.