Development of an optical fibre array fluorosensor for monitoring in the aqueous environment

In this thesis, an in depth comparison of aqueous monitoring techniques and optical instrumentation used within the aqueous environment was fully investigated. The technique of fluorescence detection was chosen as the preferred method to be used in the novel Optical Fibre Array Fluorosensor (OFAF) developed during the work. The initial benchtop instrument development and testing of the single probe/array white light system as well as the laser single probe/array system is fully described. The study of marine phytoplankton and its fluorescence properties were also fully investigated before a series of sea trials were conducted. These sea trials involved the deployment of the optical fibre probe/s under various conditions. The system was found to have a detection limit of 0.1 mu g/l for marine phytoplankton in realtime. Using dye tracers in conjunction with the OFAF was also investigated, in particular with a particulate dye tracer whose physical properties can be altered to mimic the target species under investigation. The particulate dye tracer was used in applications such as sediment movement in harbours, sewage effluent monitoring and water discharges from oil platforms in the North Sea. The system was found to have a detection limit of 10-9 M and 10-8 M respectively for Fluorescein and Rhodamine ‘B’. The OFAF offers an alternative and inexpensive method of monitoring and measuring pollutants in the aqueous environment using fluorescence techniques.