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Investigation of the properties of a single-chip potentiostat supporting three electrode cells for its operation with voltammetric and AC modes

: Köster, O.; Schuhmann, W.; Vogt, H.; Mokwa, W.

Arbeitsgemeinschaft Elektrochemischer Forschungsinstitutionen:
3rd International Symposium on Electrochemical Microsystem Technologies 2000. Program & abstracts
Garmisch-Partenkirchen, 2000
pp.41 : Lit.
International Symposium Electrochemical Microsystem Technologies <3, 2000, Garmisch-Partenkirchen>
Conference Paper
Fraunhofer IMS ()
cyclic voltammetry; electrochemical impedance spectroscopy; single-chip potentiostat; Single-Chip-Potentiostat; Voltametrie; Spektrometrie

A monolithic integrated potentiostat supporting both two- and three-electrode measurement techniques has been previously developed. Due to the fabrication of the potentiostat in a standard CMOS process, both power consumption and chip size are kept to a minimum. Hence, the single-chip potentiostat can be mounted close to the sensor and faint signals of microelectrodes can be shielded effectively from environmental noise components.
In order to enable positive and negative polarisation voltages a symmetrical supply voltage is provided. Moreover, the amplification part permits currents in both directions. Thus, the polarity of the system is not fixed and both working and counter electrode may be polarised as anode or cathode. The wide redox current input range (up to ±1.5 µA) and the rail-to-rail voltage output (-180 mV nA-1) allows the use of the single-chip potentiostat together with a variety of microelectrode types.
Here, we report on the properties of the single-chip potentiostat when operated with DC and AC polarisation voltages. In addition, linear potential sweeps have been applied to perform dynamic electrochemical investigations by means of cyclic voltammetry. The measurements have been performed using ultra-microelectrodes in supporting electrolytes containing either [Fe(CN)6]4-/3- or [Ru(NH3)6]2+/3. The measured cell potentials and redox currents were compared with the theoretical values. Moreover, a direct comparison with the performance of a conventional laboratory potentiostat was made. The transfer function and the phase lag of the potentiostat have been measured using a dummy cells. The thus obtained transfer functions could be successfully used to determine related correction terms which enable to set-up electrochemical impedance spectroscopy (EIS) at microelectrodes.
From the results we conclude that this single-chip potentiostat provides a cheap and powerful tool for electrochemical investigations using microelectrodes.