Fabrication of Fe3C/Fe-N-C nanozymes-based cascade colorimetric sensor for detection and discrimination of tea polyphenols
Xiuping Wu, Zhicheng Wang, Dongyan Li
Abstract
Tea polyphenols as antioxidants are effective scavengers of reactive oxygen species, play important roles in various biological processes. Tea polyphenols are a kind of polyhydroxy compounds, whose detection and discrimination are of great significance and still remain challenges. Here, we synthesized a Fe3C/Fe-N-C catalyst that exhibited excellent oxidase mimic activity. It can catalytically oxidized 3,3′,5,5′-tetramethylbenzidine (TMB) to blue oxidized TMB (oxTMB), which was applied in the detection of tea polyphenols and their monomers, such as epigallocatechin gallate (EGCG), epigallocatechin (EGC), epicatechin gallate (ECG), and epicatechin (EC). Furthermore, a chromogenic sensing platform on the basis of Fe3C/Fe-N-C, TMB and tea polyphenols monomers was performed for further detecting Ag+, respectively. These continuous measurement channels were designed as the sensor arrays, and EGCG, EGC, ECG, and EC can be discriminated by the pattern recognition method at the concentration of 50 μM. This research offered a new strategy through the cascade colorimetric sensor arrays for detection and discrimination of tea polyphenols monomers.