Characterization of Ag/AgCl electrode manufactured by immersion in sodium hypochloride acid for monitoring chloride content in concrete

Abstract In order to improve product efficiency and reduce the manufacturing cost, the chloride ion (Cl − ) selective electrode was prepared through immersing silver wire in the sodium hypochloride acid (SHA) solution. The performances, such as reversibility and responding time, sensitivity and limit of detection, long-term stability and reliability, of this electrode were investigated in simulating concrete pore solutions as well as concrete. Results revealed that the electrode potential exhibited good Nernst response to Cl − content. Besides, the detection limit at pH 13.5 and lower pH values was ca. 10 −3 and 10 −4  mol L −1 , respectively. The electrode coating indicated well stability over an immersion period of three months in solutions with Cl − . Furthermore, the electrode was capable to provide reliable and sustained real-time information by which the total Cl − content could be calculated. Therefore, the Cl − selective electrode is a promising tool because the electrode fabricated by the SHA technique enables us to get low-cost, miniaturized and reliable long-term sensors for Cl − monitoring.