Development of paper-based analytical devices for particulate metals in welding fume

Abstract

Exposure to metal-containing particulate matter places a tremendous burden on human health. Studies show that exposures lead to cardiovascular disease, asthma, flu-like illnesses, other respiratory disorders, and to increased morbidity. Individuals who work in occupations such as metalworking, construction, transportation, and mining are especially susceptible to unsafe exposures because of their proximity to the source of particle generation. Despite the risk to worker health, relatively few are routinely monitored for their exposure due to the time-intensive and cost-prohibitive analytical methods currently employed. The current paradigm for chemical speciation of workplace pollution is outdated and inefficient. Paper-based microfluidic devices, a new type of sensor technology, are poised to overcome issues associated with chemical analysis of particulate matter, specifically the cost and timeliness of exposure assessment. Paper sensors are designed to manipulate microliter liquid volumes and because flow is passively driven by capillary action, analysis costs are very low. The objective of this work was to develop new technology for rapidly measuring Ni, Cu, Fe, and Cr in welding fume using easy-to-use paper devices. This dissertation covers the development of two techniques for quantifying metal concentration: spot integration and distance-based detection. Metal concentrations as low as 0.02 ppm are reported. A method for controlling reagent deposition as well as a new interface for multiplexed detection of metals, is discussed.