Integrated microanalytical system with electrochemical detection

A complete microanalytical system for ionometric measurements in liquids with self-testing and self-calibration capabilities has been developed. Several advanced microtechniques are used leading to a modular setup consisting of two basic units: (i) a sensor/actuator unit and (ii) a controller unit for signal handling, actuator control and system management. As sensors ion sensitive field effect transistors (ISFET) are mounted in a plexiglass microflow cell; their alternate contact with sample and calibration solution is achieved with micropumps. These pumps are also made of polymeric materials. A special aspect of the system is the transport of liquid by means of gas pumping (air). The stacked arrangement of all components results in small overall dimensions of the system. The principal system functions have been demonstrated, and short measurement cycles were observed.