| Advances in technology have impacted every aspect of our lives. It is therefore not surprising that these advances have changed the way we interact with our environment to gather information. The ripple effects of this are far reaching in that they encompass everything from ordinary scientific research to medicine. Research has moved outside the actual laboratory adding requirements of portability, ruggedness and cost efficiency to instruments that were previously required to provide accurate reliable data.;In war zones the need for accurate medical analysis of deployed military personnel has given rise to research on portable, robust, accurate methods to analyze blood and tissue samples. While in general medicine the need to diagnose illness faster and reduce laboratory processing times has led to advancements in both technique and equipment.;Fluorescence detection is a long-practiced method of analysis. It is used for a wide range of applications such as tracking leaks in pipes, an anti-counterfeiting aid and detection and analysis in the medical industry.;With this motivation in mind a new method of integrating microfluidics with photodiodes for compact, on chip analysis is presented. Optimization of GaP photodiodes and avalanche photodiodes to be used as photodetectors in this system is explored. Integration of microfluidic capillaries with GaP photodiodes was achieved and successfully used to detect ciprofloxacin concentrations down to 1 ppb. Extension of the detection range was achieved by switching to silicon photodiodes and integrating a commercially available linear variable filter for wavelength detection and differentiation. By incorporating low cost LEDs a comprehensive system for fluorescence detection has been achieved. Fluorescein, a commonly used fluorescence marker, was excited at 470 nm and its absorption and emission spectra were obtained using this system. As a comparison the same material was characterized with a commercially available spectrofluorophotometer. It was found that the shape of the curves from the two systems was in conformity. |
