Determination of electroactive organic acids by anion-exchange chromatography using a copper modified electrode

An ion-chromatographic method combined with electrochemical detection at a copper-based chemically modified glassy carbon electrode (Cu-GC) has been s hown to provide a simple analytical approach for the determination of some common organic acids in alkaline medium. Under the optimized isocratic chro matographic conditions (i.e. 0.1 M NaOH plus 80 mM CH3COONa), organic acids such as gallic, ascorbic, gluconic, lactobionic, galacturonic and glucuron ic acid could be separated in less than 20 min. Under constant potential am perometric detection (i.e. 0.55 V vs. Ag-AgCl) the Cu-GC modified electrode allowed detection limits between 2 and 5 pmol for all investigated organic acids while the linear dynamic range spanned generally over three orders o f magnitude. Examples of applications included the separation and quantitat ion of some common organic acids in vinegar, honey and tea samples, are giv en. (C) 2001 Published by Elsevier Science B.V.