Fabrication of electrochemical interface based on boronic acid-modified pyrroloquinoline quinine/reduced graphene oxide composites for voltammetric determination of glycated hemoglobin

Abstract A voltammetric sensor for determination of glycated hemoglobin (HbA 1c ) was developed based on the composites of phenylboronic acid-modified pyrroloquinoline quinine (PBA-PQQ) and reduced graphene oxide. After the electrodeposition of reduced graphene oxide (ERGO) on the glassy carbon (GC) electrode, PQQ multilayer was decorated on the surface of the ERGO/GC electrode via potential cycling. Further modification with PBA would lead to the formation of the working electrode, namely PBA-PQQ/ERGO/GC electrode. PQQ on the electrode exhibited a quasi-reversible electrode process with 2-electron transfer and 2-proton participation, and the electron transfer efficiency was further enhanced by the introduction of ERGO layer. The complexation of PBA with HbA 1c through specific boronic acid–diol recognition could cause the change of the oxidation peak current of PQQ on the electrode, which was utilized for HbA 1c detection. Under the optimized conditions, the PBA-PQQ/ERGO/GC electrode provided high selectivity and high sensitivity for HbA 1c detection with a linear range of 9.4–65.8 μg mL −1 and a low detection limit of 1.25 μg mL −1 . The fabricated sensor was also successfully applied to determine the percentages of HbA 1c in whole blood of healthy individuals.