Oriented growth of cross-linked metal-organic framework film on graphene surface for non-enzymatic electrochemical sensor of hydrogen peroxide in disinfectant.

High-density and cross-linked copper-based metal-organic framework (Cu-MOF) sheets were successfully prepared via a simple oriented growth method on a carboxylated graphene-modified electrode surface. Hydrogen peroxide (H2O2) was selected as a model molecule to examine the performance of the thin film of Cu-MOF/graphene. The proposed sensor showed an extended linear detection range from 2.00 × 10-7 to 1.85 × 10-4 mol L-1 (R = 0.998), a high sensitivity of 0.792 A (mol L-1)-1, and a low detection limit of 6.7 × 10-8 mol L-1, due to the synergistic catalysis from the porous structure and favorable electron transfer mediating function of the electroactive Cu-MOFs and the high conductive property of the graphene. The reduction peak current of H2O2 changed less than 3.7% in the presence of 57-fold high concentrations (2.0 × 10-4 mol L-1) of the potential interfering species. The good selectivity of the prepared modified electrode was acquired by the size exclusion (molecular sieving) for H2O2 because of the proper pore shape and pore size of Cu-MOFs. The feasibility of the assay was verified by test of H2O2 in disinfectant samples. The proposed strategy presents valuable information related to the construction of non-enzymatic electrochemical sensors.