Titration-on-a-chip, chemical sensor-actuator systems from idea to commercial product

The earliest reports of integrated chemical sensor-actuator devices to perform coulometric acid-base titrations date back almost 20 years. Recently a first commercial instrument appeared that allows to perform very rapid, accurate acid-base determinations with a solid-state probe and no need for liquid titrants. This paper reviews some of the early developments and shows the effort that has been undertaken to bring this technology to routine use in the analytical laboratory and beyond.