Fabrication of a reusable electrochemical platform based on acid-responsive host-guest interaction with D- cyclodextrin

A reusable electrochemical glassy carbon electrode (GCE) platform based on the acid-responsive host-guest interaction between D-cyclodextrin (D-CD) and benzimidazole (BM) derivatives was developed. The D-CD can specifically recognize the BM derivative through the acid -responsive host-guest interaction. The electrode was first modified by eletrografting to immobilize a diamine linker (Boc-EDA), resulting in GCEBoc-EDA in which one amine was used for covalent immobilization to the electrode and another Boc protected amine was used to solidphase synthesis on following step-by-step modifications on the electrode. After deprotection of the Boc group on the GCEBoc-EDA, carbonyldiimidazole (CDI)-activated D-CD was coupled with -NH2 on the electrode to result in GCED-CD. Due to the nonspecific interaction, we further improved the GCED-CD electrode by introducing immobilized poly(ethylene glycol) methyl ether (PEG-Me) to result in GCED-CD/PEG-Me, along with optimized procedures. CV, DPV, and EIS methods were applied for recording the electrochemistry signals. We utilized GCED-CD/PEGMe to investigate the host-guest interaction and found the electrochemical signal exhibited dynamic behavior. The GCED-CD/PEG-Me was able to regenerate the D-CD surface more than 20 times after HCl acidic washes. We further investigated the interaction of carbendazim (CBZ), a commonly used fungicide in the agriculture and food industry, and observed a positive electrochemical response. The sensor design has potential applications in ensuring food safety.