This Small Business Innovation Research Phase I project aims to develop a sensitive and cost effective colorimetric bioassay for perchlorate determination in environmental samples. Perchlorate is known to affect thyroid hormone production potentially leading to neuropsychological development deficiencies. The technique proposed will take advantage of the reported ability of the nitrate reductase enzyme to reduce perchlorate to chlorite and a highly sensitive colorimetric assay for the quantitative measurement of low-level chlorite concentrations. The chlorite assay is based upon the enzymatic reaction between chlorite and horseradish peroxidase resulting in the quantitative production of chlorine dioxide which further chemically reacts with o-dianisidine to yield a yellow color. Once a nitrate reductase has been optimized for perchlorate reduction, feasibility of the technique will be dependent on the sensitivity and accuracy of the bioassay when applied to environmental samples. This proposed bioassay will create a simpler, more efficient, and cost effective method to detect low levels of perchlorate in environmental samples. Adaptation to a dipstick type test will also aid in field site analysis and provide a commercial diagnostic kit. With over 90 known perchlorate releases throughout 35 US states, this technology will benefit businesses, environmental service firms, site owners, and federal, state, and local government entities in their efforts to protect and remediate water supplies
