Electrochemical aptasensor with signal amplification strategy of covalent organic framework-derived carbon material for ultrasensitive determination of carbendazim

The inadequate conductivity inherent in some covalent organic frameworks (COFs) presents a challenge for their practical use in electrochemical sensors. To enhance the electrical conductivity of COFs, a high-temperature carbonization process can be employed to carbonize COFs in an inert atmosphere, resulting in the production of COF-derived porous carbon materials. In this study, a highly conductive COF-derived carbon material (COF-T800) was obtained through the calcination of a COF known as TPB (triphenylbenzene)-DMTP (dimethoxyterephthaldehyde)-COF. Cyclic voltammetry (CV) current responses of the TPB-DMTP-COF electrode, when exposed to [Fe(CN)6]3−/4−, were found to be lower compared to those of a bare glass carbon electrode (GCE). However, after the carbonization of TPB-DMTP-COF, the COF-T800 electrode exhibited significantly higher current responses than bare GCE. The oxidation current response of COF-T800/GCE in [Fe(CN)6]3−/4− was 3.3 times greater than that of TPB-DMTP-COF, demonstrating superior conductivity for this carbonized material. Subsequently, COF-T800 was employed as an electrochemical aptasensor substrate for signal amplification. This aptasensor had ultrasensitive determination of carbendazim (CBZ) with a linear response from 1.0 × 10−12 to 1.0 × 10−7 M. The detection limit of CBZ was 4.0 × 10−13 M. This aptasensor demonstrated high selectivity and applicability for CBZ. The COF-T800-based electrochemical aptasensor was utilized for detecting CBZ in actual samples with success.