LAUSR

Abstract Fluoride constitutes an essential component for the formation of hard bones and teeth. However long-term excessive intake of fluoride causes chronic poisoning changes in the body. Therefore, the determination of its content is of great significance. Herein, a sensitive SERS quantitative analysis method was proposed to detect F−. Trace Fe3+ exhibited strong catalysis of H2O2 oxidizing 3, 3′, 5, 5′-tetramethylbenzidine (TMB) under the ultrasonic irradiation, and the reaction product called TMB diimine (TMBOX) not only had strong fluorescence, but also had SERS activity in the silver nanosol substrate. Upon addition of fluoride ion (F−), the stable complex of [FeF6]3− formed, and could inhibit the catalytic action of Fe3+, resulting in the SERS and fluorescence signal decreasing due to the TMBOX concentration decreasing. In the range of 2–1000 nmol/L F−, the SERS intensity ΔI decreased line with the concentration increased, with a detection limit of 0.7 nmol/L. Based on the catalytic amplifying strategy and the TMBOX molecular probes, ultratrace Fe3+ could be also detected by SERS and fluorescence methods.