Document Type

Theses, Ph.D

Rights

This item is available under a Creative Commons License for non-commercial use only

Publication Details

Successfully submitted for the award of Doctor of Philosophy (Ph.D) to the Dublin Institute of Technology 2007.

Abstract

This research thesis describes the design, construction and testing of a novel modular mid-infrared fibre optic sensing system for the detection of hydrocarbons in water. It is the adverse effects to these hydrocarbon pollutants on flora and fauna that has led to the development of sensing systems for their detection and quantification. The key sensor design feature, its modularity, utilises simple low cost commercially available optical components, which are inherently suited to construct compact rugged sensing systems to perform in-situ measurements which are ideally preferred for environmental sensing. The various laboratory-based prototypes constructed weee calibrated for two target analytes over a range of analyte concentrations. From the final polymer coated fibre optic sensing system a limit of detection for benzene of 500 parts per million in aqueous test solutions was obtained with response times sufficient for real time quantification. Continuous development in mid-infrared optical components allows for improvement in the specification of the modular sensing system presented so that the limit of detection of the sensing system can be further decreased. In addition, detection of other polluting species may be performed by tuning or optimising the optical response of the sensing system for those compounds by using the appropriate modular components