Highly selective and sensitive recognition of histidine based on the oxidase-like activity of Cu2+ ions

Abstract

Developing simple, highly sensitive and selective sensing systems for histidine (His) is important due to its biological significance. In this report, Cu²⁺ ions serving as the oxidase mimics towards O-phenylenediamine (OPD) were investigated in detail. Experimental results revealed that the oxidase-like activity of Cu²⁺ ions is substantially higher than that of Cu/CuO nanoparticles. On the basis of these findings, a simple, highly sensitive and selective PL sensing platform for His could be developed, with a limit of detection (LOD) as low as 0.33 μM. Furthermore, experiments of His recovery in human urine samples were successfully conducted by employing the established sensing system with satisfactory results.