Highly sensitive ascorbic acid sensors from EDTA chelation derived nickel hexacyanoferrate/ graphene nanocomposites

Abstract

Significance of ascorbic acid (AA) determination has been increasing due to its importance in both human life and industrial applications. This work demonstrates the development of a highly sensitive non-enzymatic AA sensor by using Graphene/Nickel hexacyanoferrate nanocomposite (Gr/NiHCF). In this work, EDTA chelation strategy was used for the formation of homogeneously distributed NiHCF nanoparticles on graphene sheets. EDTA residue-supported pyramidal and spherical nanoparticles of NiHCF deposited on graphene sheets were used for the development of a highly sensitive AA sensor. The formation of EDTA residue supported NiHCF nanoparticles on graphene surface was confirmed by different characterization techniques (XRD, SEM, TEM, FTIR, XPS). Cyclic voltammetry (CV) of Gr/NiHCF nanocomposites confirmed the electrochemical sensing of AA by oxidation mechanism. The Sensitivity of the fabricated Gr/NiHCF based AA sensor as determined by amperometric characterization was found to be 7.029 µA µM−1 cm−2. The sensor fabricated in the present study shows much better sensitivity over other AA sensors reported in the literature. The LOD of the fabricated sensors was found as 0.25 µM. Repeatability, reproducibility, and interference studies of fabricated sensors reveal the high accuracy and selectivity of a fabricated sensor for AA measurement. Stability study of fabricated sensors showed excellent stability up to 30 days, indicating the potential usage of Gr/NiHCF for AA sensing. The real-time use of fabricated sensors in accurate determination of AA in samples like Vitamin C supplements and different fruit juices indicated their potential usage for AA measurement in real samples.