FeMoO4 based, enzyme-free electrochemical biosensor for ultrasensitive detection of norepinephrine

• Published in: Biosensors & bioelectronics Vol. 81; pp. 445 - 453
• Main Authors: Samdani, Kunda J., Samdani, Jitendra S., Kim, Nam Hoon, Lee, Joong Hee
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 15.07.2016
• Subjects: Adrenergic alpha-Agonists - analysis; Biosensing Techniques - methods; Biosensor; Biosensors; detection limit; diffusivity; Electrical measurements; Electrochemical; Electrochemical Techniques - methods; electrochemistry; electrodes; Fe (II)-Dioxygen complex; FeMoO4; Field emission; iron; Iron Compounds - chemistry; Limit of Detection; Molybdenum - chemistry; Nanorods; Nanotubes - chemistry; Nanotubes - ultrastructure; neurotransmitters; Norepinephrine; Norepinephrine - analysis; Oxidation; Oxidation-Reduction; Performance enhancement; scanning electron microscopy; Transmission electron microscopy; Voltammetry; X-ray diffraction; FeMoO4; Norepinephrine; Fe (II)-Dioxygen complex; Biosensor; Nanorods; Electrochemical; FeMoO
• ISSN: 0956-5663; 1873-4235; 1873-4235
• DOI: 10.1016/j.bios.2016.03.029

Herein, FeMoO4 (FM) nanorods were synthesized by a template-free, facile, hydrothermal method in an aqueous medium. The surface morphology of FeMoO4 was identified with field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). X-ray diffraction (XRD) was performed to identify the crystallographic nature of the as-synthesized FeMoO4. The as-synthesized material was used as an active electrode material for the oxidation of a neurotransmitter (i.e. norepinephrine (NE)) by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. FeMoO4 possesses polycrystallanity and bimetallic character, which helps to enhance the performance of the FM/GCE as compared to the GCE. The enhanced performance was also due to the formation of Fe (II)-dioxygen complexes, which catalyze the oxidation of NE. Meticulous observations taken from CV studies proved the diffusion-controlled nature of the reaction with a diffusion coefficient of 1.10×10−4cm2/s and a standard heterogeneous rate constant of 4.078×10−3cm/s. The amperometric response of NE on the FM/GCE showed a linear increase in the current between 5.0×10−8M and 2.0×10−4M with a detection limit of 3.7×10−9M. In the amperometric study, the time required to reach the 98% steady state response, after successive additions of 50nM NE, was less than 3s. The FM/GCE showed good sensitivity, and stability for the determination of NE. •Synthesis of FeMoO4 nanorods by facile, template free hydrothermal method was carried out in aqueous medium.•FeMoO4 was then first time used as biosensor for norepinephrine detection by CV.•The probable oxidation mechanism of NE based on Fe (iI)-dioxygen complex formation was proposed.•Low detection limit (3.7×10−9M) was achieved with FeMoO4 nanorods without any modifier.•The FM/GCE showed good sensitivity, selectivity, and stability towards the determination of NE.