Miniaturised total chemical-analysis systems (µTAS) that periodically convert chemical into electronic information

A miniaturized total analysis system (µTAS) was originally defined as “a system that periodically performs ALL sample handling steps required to translate chemical into electronic information at a location that is extremely close to the point of sample collection”(Manz, Sens Actuators B-Chem, 1990). Following rapid progress in developing functional units, the integration of these units to allow the automated execution of the analytical workflow has proven to be challenging, especially when taking out-scaling of manufacturing into account. Over almost three decades, scientists and engineers have worked together and microfluidic units have become part of a wide range of instruments. Growing demands from diagnostics sector for point of collection analysis have driven the development of functionally integrated microfluidic devices with sample in/answer out capability. The focus of this review is on the systems that go one step further and are capable of periodically executing the analytical protocol to translate the chemical information into electronic data. With sampling and chip to world interfacing fundamental to a µTAS’ operation, an overview of flow-based sampling techniques is provided, followed by selected examples of µTASs applied for monitoring environmental, biochemical, and physiological processes and extra-terrestrial exploration. Building on the expertise developed in the development of Lab on a Chip systems and innovations in manufacturing, automation and control, the future outlook for µTASs to stream the chemical data required to advance our understanding and subsequently control of the processes in- and around us is looking bright.