Kumar Deepak, Bhatt Deepanshu, Garg Deepa, Kumar Vijayesh, Sachdev Abhay, Matai Ishita
Materials Science & Sensor Applications Division, CSIR-Central Scientific Instruments Organization (CSIR-CSIO), Chandigarh-160030, India.
Academy of Scientific and Innovative Research, Ghaziabad-201002, India.
Anal Methods. 2025 May 22;17(20):4124-4137. doi: 10.1039/d5ay00144g.
The integration of a nanocomposite composed of cuprous oxide-graphene nanoplatelet hydrogel (CuO-GNP hydrogel) has been investigated as an electrochemical interface for nitrite (NO) detection. The nanocomposite hydrogel was prepared through the sonochemical technique and characterized by Field Emission Scanning Electron Microscopy (FE-SEM), EDX (energy dispersive X-ray analysis), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). Electrochemical performance was further evaluated using Electrochemical Impedance Spectroscopy (EIS), Cyclic Voltammetry (CV), and Differential Pulse Voltammetry (DPV). CuO provides a catalytic active site that lower the activation energy for NO oxidation, while GNPs enhance the electrode conductivity and increase the surface area for superior electron transfer. Additionally, a PDMS-based microfluidic device was developed and integrated with an electrochemical detection system, enabling continuous and real-time monitoring of NO. A syringe pump was used to maintain a stable NO solution flow through the microfluidic channels at a 10 μL per min flow rate, ensuring sufficient diffusion of NO ions to the electrode surface, and preventing excess analyte accumulation that could lead to signal distortion. The integrated microfluidic sensor exhibited excellent electrochemical performance, achieving a high sensitivity of 13.97 μA μM cm and a low detection limit (LOD) of 0.56 μM, with a linear range of 5-130 μM. CuO-GNP hydrogel/SPCE exhibited excellent selectivity and reproducibility for NO sensing. The developed sensor demonstrated good recovery percentages in sausages, pickled vegetables, and water samples, confirming its suitability for the food industry.
已对由氧化亚铜-石墨烯纳米片水凝胶（CuO-GNP水凝胶）组成的纳米复合材料作为亚硝酸盐（NO）检测的电化学界面进行了研究。通过声化学技术制备了纳米复合水凝胶，并通过场发射扫描电子显微镜（FE-SEM）、能谱仪（EDX，能量色散X射线分析）、X射线光电子能谱（XPS）、X射线衍射（XRD）和傅里叶变换红外光谱（FTIR）对其进行了表征。使用电化学阻抗谱（EIS）、循环伏安法（CV）和差分脉冲伏安法（DPV）进一步评估了电化学性能。CuO提供了一个催化活性位点，降低了NO氧化的活化能，而GNPs提高了电极的导电性并增加了表面积，以实现卓越的电子转移。此外，还开发了一种基于聚二甲基硅氧烷（PDMS）的微流控装置，并将其与电化学检测系统集成，能够对NO进行连续实时监测。使用注射泵以每分钟10 μL的流速维持稳定的NO溶液流经微流控通道，确保NO离子充分扩散到电极表面，并防止可能导致信号失真的过量分析物积累。集成的微流控传感器表现出优异的电化学性能，实现了13.97 μA μM cm的高灵敏度和0.56 μM的低检测限（LOD），线性范围为5-130 μM。CuO-GNP水凝胶/玻碳电极（SPCE）对NO传感表现出优异的选择性和重现性。所开发的传感器在香肠、泡菜和水样中显示出良好的回收率，证实了其在食品工业中的适用性。
