Redox based electrochemical affinity sensor for detection of aqueous pertechnetate anion

Rapid, selective and in-situ detection of pertechnetate (TcO4-) in multicomponent matrices consisting of interfering anions such as the ubiquitous NO3- and Cl- or the isostructural CrO42- is challenging. Present sensors lack the selectivity to exclude these interferences, or the sensitivity to meet detection limits that are lower than the drinking water standards across the globe. This work presents an affinity based electrochemical sensor for TcO4- detection that relies on selective reductive precipitation of aqueous TcO4- induced by a 1,4-benzenedimethanethiol capture probe immobilized on an electrode platform. This results in a direct decrease of the electron transfer current, the magnitude of the decrease being proportional to the amount of TcO4- added. Using this approach, a detection limit of 1×10-10 M was achieved, which is lower than the drinking water standard of 5.2×10-10 M set by United States Environmental Protection Agency. The proposed approach shows selectivity to the TcO4- anion, allowing ...