ZnO-Fe2O3 based electrochemiluminescence sensor for sensitive detection of malathion

Metal oxides containing iron and zinc (ZnO-Fe 2 O 3 ) combined with ruthenium bipyridine [Ru(bpy) 3 2+ ], graphene oxide (GO) and multi-walled carbon nanotube (MWNTs) were applied in the field of electrochemiluminescence (ECL). And a new solid-state ECL sensor for malathion determination by modifying ZnO-Fe 2 O 3 , Ru(bpy) 3 2+ , GO@MWNTs, Acetylcholinesterase (AchE) and Nafion on the electrode surface. The synthesized ZnO-Fe 2 O 3 and GO@MWNTs with large specific surface area were used as carrier to anchor Ru(bpy) 3 2+ and AchE, respectively. ZnO-Fe 2 O 3 and GO@MWNTs can also be used as accelerators to promote electron transfer of the system. ZnO-Fe 2 O 3 was also involved in the luminescence reaction, which increased the sensitivity of the system together with Ru(bpy) 3 2+ . Taking advantages of the electrocatalysis and electron transport capacity of ZnO-Fe 2 O 3 and GO@MWNTs, the sensor obtained stable and amazing ECL response. The ECL response value decreased after malathion was introduced. In the range of 6.6 × 10 −11 to 6.6 × 10 −7 M, the decrease value (ΔI) was linearly related to the logarithm of malathion concentration, and the detection limit was 2.2 × 10 −11 M. The method was simple and stable, and can be used to determine malathion in vegetable samples.