传统的类氧化酶(OXD)纳米酶主要依靠O2介导的超氧阴离子(O2·-)过程进行催化氧化和有机磷(Ops)检测。而在实际检测过程中,O2的浓度是不恒定的,可以很容易地随着外部环境的变化,扭曲检测结果。在这里,设计了具有核壳纳米结构的高氧化性Au@MnO2-X纳米酶,可触发从内部Au核到外部超薄MnO2-X层的大量电子转移。根据实验和理论计算,Au@MnO2-X的核壳纳米结构和超薄MnO2-X导致较大的表面缺陷,高氧空位和MnIII比率。因此,特殊结构的Au@MnO2-X纳米酶具有高度氧化性,并且催化氧化可以仅通过电子转移而不是O2介导的O2·-过程来完成。基于此,使用均相电化学(HEC)建立了一种不依赖氧的超灵敏纳米酶传感器,在0.039ngmL-1的LOD下检测到其Ops。结合3,3'的紫外可见光谱,5,5'-四甲基联苯胺(TMB),五个运算的线性判别分析,即,Ethion,氧化乐果,Diazinon,甲基毒死蜱和双歧杆菌取得了优越的辨别后果。因此,基于强氧化纳米酶的HEC为开发高性能电化学传感器提供了新的途径,并展示了对实际样品中农药残留测定的潜在适用性。
Traditional oxidase-like (OXD) nanozymes rely primarily on O2-mediated superoxide anion (O2·-) process for catalytic oxidation and organophosphorus (Ops) detection. While during the actual detection process, the concentration of O2 is inconstant that can be easily changed with the external environment, distorting detection results. Herein, highly-oxidizing Au@MnO2-X nanozymes with core-shell nanostructure are designed which trigger substantial electron transfer from inner Au core to outer ultrathin MnO2-X layer. According to experimental and theoretical calculations, the core-shell nanostructure and ultrathin MnO2-X of Au@MnO2-X result in the large surface defects, high oxygen vacancies and MnIII ratios. The specially structured Au@MnO2-X nanozymes are therefore highly-oxidizing and the catalytic oxidation can be completed merely through electrons transferring instead of the O2-mediated O2·- process. Based on this, an oxygen independent and ultrasensitive nanozyme-based sensor is established using homogeneous electrochemistry (HEC), its Ops is detected at a LOD of 0.039 ng mL-1. Combined with the UV-vis spectrum of 3,3\',5,5\'-tetramethylbenzidine (TMB), the linear discriminant analysis of five Ops i.e., Ethion, Omethoate, Diazinon, Chlorpyrifos methyl and Dipterex has achieved superior discrimination results. Therefore, HEC based on strong oxidizing nanozymes provide a new avenue for the development of high-performance electrochemical sensors and demonstrate potential applicability to pesticide residue determination in real samples.