A novel molecular imprinted quartz crystal microbalance sensor for fenamiphos determination based on boron-sulphur co-doping ultra-thin graphitic carbon nitride incorporated Cu-MOF

Abstract

Fenamiphos (FEN) as organophosphorus insecticide is frequently used in recent years to control many nematode pests. Nonetheless, its important adverse effects have currently attracted attention in humans and the ecological environment. In present study, a novel flow injection type portable quartz crystal microbalance (QCM) sensor based on boron and sulphur co-doping ultra-thin graphitic carbon nitride (g-C3N4) incorporated Cu-MOF (BS-g-C3N4-CuMOF) nanocomposite was developed and used for FEN determination in apple juice samples. For this aim, the preparation of BS-g-C3N4-CuMOF nanocomposite via in situ solvothermal procedure was performed with high synthesis yield. Then, molecular imprinted QCM sensor based BS-g-C3N4-CuMOF was prepared in existence of methacryloylamidoglutamic acid (MAGA) as monomer and N,N′-azobisisobutyronitrile (AIBN) as initiator via UV polymerization. This QCM sensor revealed the linearity of 1.0×10-9-2.0×10-8 mol/L with a detection limit (LOD) of 3.3×10-10 mol/L for FEN molecule, suggesting the successful development of sensitive molecular imprinted QCM sensor. The prepared sensitive molecular imprinted QCM sensor was applied to apple juice sample with high recovery. Moreover, the high selectivity of molecular imprinted QCM sensor was confirmed in presence of the competing agents in the apple juice sample and the prepared QCM sensor was shown to detect FEN at least 5 times more selectively than other competing agents. In addition, the proposed sensor in correlation with standard high end measurements like GC-MS was validated and there was no significant difference between the results of the proposed sensor and GC-MS method. The low relative standard deviation (RSD) value of 20 independent QCM signals also suggested the high reproducibility of the QCM sensor. Finally, its high repeatability and reusability were presented in detail.