基于CoNi双金属有机框架材料比色检测抗坏血酸及总抗氧化能力OA

A CoNi bimetallic metal-organic framework(CoNi-MOF)was synthesized via a room-temperature co-precipitation method.Benefiting from the bimetallic synergistic effect between Co and Ni,CoNi-MOF showed significantly superior oxidase-like(OXD)activity compared with monometallic MOFs,and could catalyze the chromogenic substrate 3,3',5,5'-tetramethylbenzidine(TMB)to produce a color reaction.In the presence of ascorbic acid(AA),the color reaction was markedly inhibited.On this basis,a colorimetric sensing platform for AA detection was constructed.The platform exhibited a linear detection range of 1-16 μmol/L toward AA,with a limit of detection(S/N=3)of 0.34 μmol/L,together with good selectivity and long-term stability.It was successfully applied to analysis of total antioxidant capacity(TAC)in fresh fruits and commercial beverages.The spiked recoveries of passion fruit samples were 98.17%-101.30%,and the relative standard deviations(RSDs)were all below 7%.Without addition of H2O2,this detection system was simple to operate and low in cost,which provided a new analytical method for food quality monitoring and antioxidant capacity evaluation,and expanded new horizons for application of bimetallic MOF nanozymes in sensing analysis.