An Integrated Amperiometric Sensor for in situ Environmental Monitoring

In the modern era, some of the most serious causes for public health problems can be attributed to environmental pollution. Proper monitoring of environmental conditions helps us to control the pollution in an effective manner. This paper introduces a robust, self-contained, inexpensive integrated amperiometric microelectrode sensor that can be used for in situ environmental monitoring. The work primarily focuses on the design, implementation and integration of an amperiometric CMOS sensor chip with a microelectrode sensor device in order to measure the current flowing through the working probe (microelectrode sensor) and the reference probe, when they are immersed in the test solution. The magnitude of the current signal, of the order of nanoamperes, is shown to be dependent on the characteristics (oxygen content) of the solution being evaluated by the system. The integration of the microelectrode sensor with the sensor chip is done with the help of a Printed Circuit Board. The microelectrode sensor device may be replaced by a NEMS based sensor device for applications requiring further miniaturization, like that in the biomedical field where the solution under test may be a biofilm.