Electrochemical Detector for HPLC Separations

Another common group of HPLC detectors are based on electrochemical measurements such as amperometry, voltammetry, coulometry, and conductivity. The illustration below, for example, shows an amperometric flow cell. Effluent from the column passes over the working electrode, which is held at a constant potential—relative to a downstream reference electrode—that completely oxidizes or reduces the analytes. The current flowing between the working electrode and the auxiliary electrode serves as the analytical signal.