A new double signal on electrochemical aptasensor based on gold nanoparticles/graphene nanoribbons/MOF-808 as enhancing nanocomposite for ultrasensitive and selective detection of carbendazim

The fungicide carbendazim (CBZ) is a carcinogen, which is widely found in the environment. It is a broad-spectrum benzimidazole fungicide that acts by disrupting fungal cell division. To detect CBZ in water samples, an ultrasensitive and selective dual-signal electrochemical aptasensing platform based on the interaction of SH-complementary carbendazim aptamer (SH-cCBZ) and carbendazim aptamer (CBZA) was developed. Gold nanoparticles (AuNP) modified with graphene nanoribbons (GNR), which were produced from multiwalled carbon nanotubes, and Zr-based metal-organic framework (MOF-808) ([email protected]/MOF-808) were used for enhancing the signals for the first time. The SH-cCBZ produced a double-stranded structure along with CBZA. CBZ dispersed the double strands, thereby amplifying the electrochemical response. The electrochemical aptasensor showed a linear response to CBZ in the concentration range from 1.0 fmol L−1 to 100.0 pmol L−1 and 0.8 fmol L−1 to 100.0 pmol L−1 under ideal conditions. The detection limits obtained via electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV) were 0.4 and 0.2 fmol L−1, respectively. Moreover, the proposed aptasensor was used to determine the CBZ levels in Bangkok tap water and Chao Phraya river water samples, the results were in good agreement with UPLC-MS/MS. The recoveries ranged from 97.5% to 102.8%, suggesting various potential applications.