FIBRE-OPTIC SENSORS FOR CHEMICAL PARAMETERS OF INTEREST IN BIOTECHNOLOGY

Abstract

Optical fibres can be used for remotely sensing chemical and physico-chemical parameters that are of interest for proper management of bio- processes as they occur, for instance, in bioreactors. Optical sensors can offer advantages over electrochemical ones because of the lack of reference cells, the immunity towards electromagnetic interferences, and the possibility of heat sterilisation. In this contribution, the principles of waveguide spectroscopy are briefly outlined, and waveguide sensors are classified according to their working principles. The most usual approach in the development of fibre-optic sensors is to provide the end of an optical fibre with a suitable indicator chemistry or a material that responds to the parameter of interest. In contact with the sample, the intensity of reflected, scattered, or re-emitted light is the analytical signal. Representative examples of fibre-optic sensors for oxygen, pH, carbon dioxide, ammonia, electrolytes, and redox status are given. Recently developed sensors for glucose and enzymes shall also be considered. Finally, potential fields of application are presented, and current trends and concepts discussed.