Electrochemical detection of paraquat based on silver nanoparticles/water-soluble pillar[5]arene functionalized graphene oxide modified glassy carbon electrode

In this paper, silver nanoparticles (AgNPs) modified by carboxylated pillar[5]arene (CP5) were anchored on graphene oxide (GO) by pi-pi stacking interaction and hydrogen bond between CP5 molecules and GO. The obtained hybrid nanomaterials CP5-AgNPs/GO were characterized by ultraviolet-visible adsorption spectrometer, Fourier transform infrared adsorption spectrometer, and transmission electron microscopy. Testing of various electrochemical techniques displays that the CP5-AgNPs/GO modified glass carbon electrodes (GCE) show good electrocatalytic property, molecular recognition and enrichment performance toward paraquat (PQ) and exhibit high current response. Compared with other modified electrodes, such as GO/GCE and CP5/GO/GCE, CP5-AgNPs/GO/GCE shows an outstanding electrochemical response for PQ with high sensitivity of 78.8 mA mmol(-1) L cm(-2). The analytical curves for PQ obtained by differential pulse voltammetry are linear in the range from 1.0 x 10(-8) to 1.0 x 10(-5) M and from 2.0 x 10(-5) to 7.0 x 10(-5) M. The limit of detection is 1.0 x 10(-8) M (S/N = 3). This excellent performance is ascribed to the synergic electrocatalytic effect of AgNPs and GO, and the host-guest recognition of CP5 for PQ.