Determination of selected phenolic acids in beer extract by liquid chromatography with voltammetric-amperometric detection
A voltammetric-amperometric detector for liquid chromatography based on a dual electrode electrochemical cell has been developed. This detector enables voltammograms to be obtained without the charging current problems inherent in single electrode voltammetric detectors. The detector is operated by scanning the potential of the upstream (voltammetric) electrode and detecting the electrolysis product at a constant potential (amperometric) electrode downstream. The reponse at the downstream amperometric electrode thus reflects the voltammetry occurring upstream but eliminates the charging current. The voltammetric-amperometric detector produces a three-dimensional data array of current response versus both time (chromatographic domain) and potential (electrochemical domain). This data array allows for several types of post-experimental data manipulation and display in order to enhance information retrieval. In this paper, these methods of display and manipulation of voltammetric-amperometric data are demonstrated for the determination of selected phenolic acids in an extract of a commercial beer sample.