Demonstration of a Unique Nanotube-Based Arsenic Detector

Arsenic contamination in water supplies poses a severe health risk to world-wide populations. The US EPA has recently lowered As water standards from 50 ppb to 10 ppb to address this risk. Many states, including California, either have passed or are soon to pass even stricter regulations. Currently available As detection methods suffer from numerous drawbacks including non-real-time, costly, bulky, complicated, and inaccurate. The sensor demonstrated in Phase I overcomes all these obstacles. Carbon nanotubes have found exciting new applications in technologies ranging from batteries to heat transfer, and sensor technologies are now proving to hold equal potential. In Phase I, the feasibility of using ionization-based carbon nanotube sensors for As detection was successfully demonstrated by fabricating carbon sensors and measuring breakdown voltages and the variation of discharge current as a function of concentration. The objective of the Phase II effort is to optimize the carbon nanotube manufacturing process to achieve maximum performance and lower operating voltages, design the extraneous sub-systems, and test the complete sensor. Optional tasks handle prototype system installation and field testing and an investigation of manufacturing quality control. By the end of Phase II, a full prototype sensor will have been developed, fabricated, and tested.