(Digital Presentation) Non-Enzymatic Lactose Sensor Based on Nickel Oxide Nanoparticles Modified Carbon Fiber Cloth Electrode

Abstract

Lactose (LAC) is the main sugar found mostly in milk and dairy products. LAC content is an important indication of milk quality and health issues in the food business as well as in human and animal health. The development of biosensors for lactose detection has received a lot of attention over the last 20 years due to its importance in the agricultural and healthcare industries [1-3]. In this work, an enzyme-free lactose sensor has been developed using a carbon fiber cloth electrode modified with NiO nanoparticles (NiO/CFC). At first, Ni(OH) 2 precursor of NiO nanoparticles were electrodeposited on the surface of CFC by applying a constant potential of -1.0V in an electrochemical cell containing 6 mM Ni(NO 3 ) 2 ·6H 2 O solution where CFC was used as a working, Ag/AgCl (3M KCl) as reference and Pt wire as a counter electrode. Then the electrode was calcined at 100 ℃ in the presence of oxygen for 1 hr. For the confirmation of the growth of NiO nanoparticles on CFC, morphology and chemical composition of the electrode was characterized using SEM, EDX, TEM, XRD, FT-IR and Raman spectroscopy. The electrochemical properties of NiO/CFC were investigated by applying Cyclic Voltammetry, and amperometry in a 0.1M NaOH solution. NiO/CFC exhibits a fast reaction time of less than 5 s with a linear relationship of 0.5 to 3.5 mM (R 2 = 0.97) at an applied voltage of +0.65 V (Fig. 1). The sensitivity was found to be 1.73 mA/mM/cm 2 with a detection limit of 227 µM. The interference test of the electrode was performed in glucose, ascorbic acid, and uric acid solutions, which indicated insignificant current responses compare to lactose. As a result, it provides a sensitive, simple, and rapid amperometric sensor, which opens the way to developing an enzyme-free sensing platform to detect lactose in milk. Acknowledgments Ministry of Science and Technology of Bangladesh (special allocation 2021-22) for funding this research. References G. Halpin et al. , J. Electrochem. Soc., 2022, 169, 037528. M. Jamal et al. , Sci. Rep. , 2019, 9, 4659. J. Islam et al. , PLoS ONE , 2021 16(3), e0248142. Fig. 1. Amperometric current response of the NiO/CFC electrode to sequential additions of lactose ranging from 1 to 3.5 mM into a stirred 0.1 M NaOH solution. Figure 1