Programable microfluidic processor with pumping and coulometric detecting functions

An integrated microfluidic chip to handle liquid plugs of the nL order was fabricated. The chip consisted of a T-junction, shape memory alloy (SMA) micro plumps, and an electrochemical sensor. The weight of the chip including all the components was only 1.5 g. The device was operated by a computer control system connected to the chip. Driving voltage was less than 5 V. In the detection of an analyte using this chip, the volume of a sample solution was precisely measured at the T-junction, which was then separated into a liquid plug. The plug was subsequently transported to the electrochemical sensor. As a demonstration, the concentration of hydrogen peroxide was measured by coulometry. The measured charge was clearly dependent on the concentration of hydrogen peroxide.