Multyfunctional device for electrochemical analytical methods

Abstract

The simple version of multyfunctional potentiostat-galvanostat MTech PG-410 based on microcontroller C8051F410 has been designed. The C8051F410 chip is fully integrated, low power, mixed-signal system-on-a-chip microconroller unit. It includes high-speed 8051-compatible core, precision programmable 24.5 MHz internal oscillator, 32 kbytes of on-chip flash memory, 12-bit 200 ksps analog to digital converter with analog multiplexer, two 12-bit current output digital to analog converters and 2.2 V voltage reference. The potentiostat-galvanostat controls the potential between the working electrode and the reference electrode in range ±2 V. The potentiostat-galvanostat has three ranges of measured current with manual selecting: ±0.5, ±2 and ±10 mA. The device can measure voltammograms under high sweep rate up to 4 000 mV/s. The device is equipped with RS232-USB converter based on PL2303 chip for power supply and communication with the computer through USB port. Computer program on Visual Basic 5.0 language for operating with potentiostat has been developed. This software allow to measure and visualize voltamperograms, chronopotentiograms, chronoamperograms, potentiometric and coulometric titration curves. For reduction of influence of electromagnetic noise and improvement signal/noise ratio the program makes digital processing of measured polarograms by Savitzky-Golay filter. Potentiostat-galvanostat MTech PG-410 has been successfully tested on model systems using resistive electrochemical equivalents. Also, the main measuring techniques embedded in the device were tested using well-known analysis methods: potentiometric titration of dichromate with Mohr's salt, coulometric titration of thiosulfate with electro-generated iodine and cyclic voltammetry of ferrocyanide/ferricyanide redox couple. Keywords : potentiostat, galvanostat, microcontroller C8051F410, voltammetry, potentiometry.