Detection of Pertechnetate Using Square Wave Anodic Stripping Voltammetry on Carbon Electrodes

Abstract

Technetium-99 (Tc-99) is a primary fission product of U-235, U-233, and Pu-239 and is a major constituent of radioactive waste. Tc-99 is commonly found as pertechnetate (TcO4 -), an anion that does not readily adsorb to natural sediment and is extremely mobile in environmental water systems. With concerns that radioactive waste may be leaking from sub-surface storage tanks and potentially reaching groundwater, developing detection methods for TcO4 - is important. Square wave anodic stripping voltammetry (SWASV) is a simple electrochemical technique that has yet to be investigated for pertechnetate due to the high potential required to form solid TcO2. In this work, we use SWASV with a variety of carbon electrodes to determine the optimal conditions for the detection of TcO4 - in a variety of solutions including acidic, basic and neutral pH. Carbon electrodes such as glassy carbon, boron-doped diamond, and nitrogen-doped tetrahedral amorphous carbon were examined. Carbon electrodes are ideal for the detection of pertechnetate due to their robust nature, low background current, and wide windows when compared to metal electrodes. Control studies included optimization of the deposition potential and time. In addition, calibration curves were created for each solution’s optimized parameters. Several analytical figures of merit such as the sensitivity, limit of detection, and limit of quantification were determined. This work expands upon the use of carbon electrodes for trace detection of environmentally relevant analytes.