The development of low cost autonomous chemical sensors for environmental monitoring
Cogan, Deirdre (2015) The development of low cost autonomous chemical sensors for environmental monitoring. PhD thesis, Dublin City University.
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Our ability to effectively monitor the aquatic environment is essential due to the increasing pressure on the environment from pollution, global climate change and the fact that water is an increasingly scarce natural resource. Nutrients such as nitrate and ammonia are essential for ecosystems but surplus levels of nutrients entering water bodies are a serious pollutant, causing eutrophication, contaminating drinking water and killing ecosystems which can cost nations up to $2.2 billion per year. There is therefore a growing need for low cost, remote sensing systems which can be deployed in sufficiently large numbers to ensure that data on key water quality parameters is readily available.
This project has the overall objective of developing low cost analytical platform for autonomous monitoring of environmental water quality. This will be achieved by further development of existing monitoring platforms developed at DCU combined with modified chemical methods in order to reduce the fabrication cost of the devices by an order of magnitude.
Through this strategy, a microfluidic sensing platform for the direct determination of nitrate in water using chromotropic acid has been developed. The chromotropic acid method has been modified to facilitate its implementation into an autonomous platform, resulting in a quick and simple procedure to measure nitrate. The device incorporates a low cost, highly sensitive detection with excellent correlation to the standard method, ion chromatography. Ultimately, this system provides a base in terms of monitoring waters for nitrate levels in situ in a rapid, simple and inexpensive manner.
For the determination of ammonia, a simplified variation of the Berthelot method has been integrated into an autonomous sensing platform for reliable, reproducible results showing excellent correlation with ion chromatography.
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