The impedance-titrator : A novel setup to perform automated pH-dependent electrochemical experiments

A new device for performing electrochemical experiments under automatic change or control of the solution pH was developed. The electrochemical cell consists of a thermostatted glass cell, counter electrode, reference electrode and working electrode, pH sensor, stirrer and gas purging system. A control box and a potentiostat equipped with a frequency response analyser form the electronic equipment, while a piston buret allows dosing the solution of interest e.g. a sodium hydroxide solution. Various modes are available for scanning the pH range or keeping the pH constant if a hydroxide consuming reaction shall be observed at a constant pH value, all during electrochemical experiments are performed. Two application examples are given to demonstrate the versatility of the impedance titrator. one addresses the determination of the breakdown pH value of anodised aluminium and the other quantifies the consumption of zinc during transient formation of zincate precipitates.