As outlined by measure 7061A from the Environmental Protection Agency, atomic absorption/gaseous hydride is the current method for arsenic detection in wastes, soils, and groundwater. The method begins with a nitric or sulfuric acid digeste. Using tin chloride, the arsenic is reduced into its trivalent state and converted into a volatile hydride. The hydride is then swept into an argon-hydrogen flame.The subsequent radiation is read by a spectrophotometer; the result is proportional to the arsenic concentration in the environmental sample. This process requires highly trained technicians and a significant delay for laboratory proceedings to be completed, costing up to $150 per sample.
Evidently, the acid digest method for arsenic detection is simply not reasonable for the impoverished people of Bangladesh, who face a severe crisis in arsenic contamination. It is estimated that nearly 57 million citizens of the Bengal basin are currently consuming water that exceeds the World Health Organization’s standard of arsenic concentration at ten parts per billion (Henke, 2009). WHO investigators estimate that more than 20% of deaths in Bangladesh could be attributed to dangerous concentrations of arsenic in tube wells. Additionally, the United States military remains concerned about exposure of troops to unsafe environmental conditions, including arsenic-contaminated drinking water. These issues show an urgent need for a field-effective, inexpensive sensor for arsenic.