Date of Award


Degree Type


Degree Name

Doctor of Philosophy in Mechanical Engineering


Mechanical, Industrial and Systems Engineering

First Advisor

Mohammad Faghri


Nitrate is a naturally occurring nutrient that is part of the nitrogen cycle. Monitoring of this nutrient in water bodies ensures its safety for consumption, guards against water nutrient pollution, and provides oceanographers and marine scientists with data to better understand nitrogen cycling and other phenomena of interest. Currently, there are several techniques available for nitrate detection. However, they either lack the required sensitivity for use in the field, or are costly, time consuming, and require special handling of the water sample as it gets sent to a laboratory for analysis.

Paper-based technologies possess several advantages that can facilitate sensitive detection of nitrate in the field by providing an inexpensive, easy to use, portable, and disposable device. This study developed a system based on the use of a microfluidic paper-based device for detecting nitrate in seawater by incorporating different technologies to improve nitrate reduction and detection.

A new composite material improved nitrate reduction by 36% than what has been previously accomplished. This composite material was used in a novel paper-based device that utilized a folding detection zone architecture and immobilized detection reagent. This resulted in a limit of detection and quantification of nitrate of 0.53 ppm and 1.8 ppm, respectively. These results constitute over 40% enhancement from what has been previously realized for the detection of nitrate in water using paper-based technology. The results of this study also contributed to the field of paper-based technology by providing new designs, materials, insights and conclusions that further enhance and deepen the understanding of this technology.



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