| Summary: | Herein, a colorimetric copper (Ⅱ) ion (Cu2+) detection system based on the oxidization reaction of 3′3′5′5′-tetramethylbenzidine (TMB) and Ag(S2O3)23− (in aqueous solution) was designed. The detection system comprised TMB, silver nanoparticles (AgNPs) and thiosulfate (S2O32−). It was observed that AgNPs were unable to oxidize TMB to a blue color. While, Cu2+ ions could effectively catalyze the S2O32--leaching system, thereby converting AgNPs to Ag(S2O3)23−. Similar to Ag (I), Ag(S2O3)23− catalyzed the color reaction of TMB. The colorimetric copper (Ⅱ) ion (Cu2+) detection system was fabricated. Results showed that the optimal amounts of TMB and Na2S2O3 were 800 and 400 μM, respectively, and the reaction time and temperature were 40 min and 25 °C, respectively. The range of curvature tendency was 1–100 μM, with a limit of detection of 100 nM. The detection system exhibited a high selectiveness for copper ions in an aqueous solution. Furthermore, this system shows remarkable promise for monitoring the aqueous quality.
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