Construction and analytical applications of a palm-sized microcontroller-based amperometric analyzer

The design and development of a palm-sized (9 cm x 11 cm x 3 cm), cost-effective, microcontroller-operated analyzer for direct amperometric measurements is described. The low-power-consumption electronics used allow 8 h of autonomous operation with a 9 V battery (110 mAh), making thus this unit suitable for in-field measurements. Its operation is based mainly on the simple two-electrode potentiostatic mode, although the three-electrode mode is an option. The use of a microcontroller combined with analog and digital supporting circuits allows: (i) generation of the applied potential and the acquisition of analog signals with a gain auto-scaling capability; (ii) interaction with the operator for setting the measurement parameters; (iii) processing of data and displaying result on an LCD screen. Numerical data are automatically stored in memory and they can be retrieved by a personal computer through an RS232 port, either for creating measurements archives or for advanced processing. For this purpose, a program has been developed (on the LabVIEW platform) to provide a user-friendly graphical interface. The utility of this amperometric analyzer was assessed by performing experiments for the determination of ascorbic acid in standard solutions and pharmaceutical tablets. (c) 2004 Elsevier B.V. All rights reserved.