Search results

The purpose of this paper is to design and create a potentiostat that can be integrated and encapsulated within a microelectrode as a low‐cost electrochemical sensor. Recently, microsystems on sensors or lab on a chip using electrochemical detection of substances matters are pushing forward into the area of analysis. For providing electrochemical analysis, the microsystem has to be equipped with an integrated potentiostat.

The integrated potentiostat with four current ranges (from 1 μA to 1 mA) was designed in the CADENCE software environment using the AMIS CMOS 0.7 μm technology and fabricated under the Europractice program. Memory cells of 48 bytes are implemented with the potentiostat using VERILOG.

The characteristics of integrated potentiostat are strictly linear; the measured results confirm the simulated values. The potentiostat measurements error is about 1.5 percent and very low offsets are reached by the offset‐zeroing circuitry.

The detection limit of the current at the lowest range with respect to S/N ratio is about 10 nA.

The integrated potentiostat is embedded on a screen‐printed sensor and its characteristics are successfully verified. Lower range of 100 nA can be implemented on a new microchip as well as rail‐to‐rail output circuitry would increase the voltage dynamic range.

The integrated potentiostat with very good parameters is designed for a wide spectrum of electrochemical applications such as lab on a chip, embedded electrochemical systems, etc. The integrated system enables storing of information about the system measured, for instance, calibration and fabrication data of the electrochemical sensor.

Screen‐printed electrodes are widely used in the construction of sensors. The use of graphite material is preferred due to its simple technological processing and low cost. Different graphite pastes are compared for hydrogen peroxide detection. The slope of the calibration curve, linearity and limit of detection have been compared for different pastes and technologies of graphite electrode preparation. The influence of the structure of the paste on response is discussed. Physical methods of sensitivity enhancement are proposed. All results are compared with platinum electrode as technological reference.