Application of Square Wave Voltammetry for Electrochemical Detection in Gradient Elution HPLC

Abstract

The utility of square-wave voltammetry with a conventionally sized indicator electrode for use in the detection of gradient elution HPLC applications is demonstrated. A redesigned electrochemical detector cell, based upon a type of wall-jet design, provides more efficient potential control and allows the voltammetric detection. The minimum detectable quantity and linear dynamic range for the new detector design were found to be 13pg and 5 orders of magnitude, respectively, comparable to other electrochemical detectors. In the separation of a test mixture containing hydroquinone. bromohydroquinone, catechol, resorcinol, and phenylhydroquinone baseline resolution of all five components is obtained in 12 minutes using a nonlinear solvent gradient. Importantly, no change in the chromatographic baseline is observed during the course of the separation. Gradient separations of the extracts of fennel seeds and mainstream cigarette smoke are also demonstrated with no apparent change in the baseline.