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200 results on '"Rajaji, Umamaheswari"'

16. Green sonochemical synthesis of ZnCo2O4 decorated with carbon nanofibers for enhanced electrochemical detection of bisphenol A in food products.

Author

Govindharaj, Kamaraj, Govindasamy, Mani, Gokila, N, Huang, Chi-Hsien, Rajaji, Umamaheswari, Albaqami, Munirah D., and Kumar, Ramasamy Thangavelu Rajendra

Subjects
TRANSITION metal oxides, FIELD emission electron microscopy, CARBON electrodes, DRINKING water, ORANGE juice, CARBON nanofibers, SONOCHEMICAL degradation, YOGURT
Abstract

The facile sonochemical synthesis is reported of zinc cobalt oxide (ZnCo2O4) composited with carbon nanofiber (CNF). Structural, chemical, and morphological were characterized by X-ray diffraction (XRD), X-ray photoluminescent spectroscopy (XPS), field emission scanning electron microscopy (FESEM), and transmittance electron microscopy (TEM), respectively. ZnCo2O4/CNF-modified GCE was applied to the detection of bisphenol A (BPA). The modified GCE shows enhanced sensing performance towards BPA, which includes a linear range (0.2 to 120 μM L−1) alongside a low limit of detection (38.2 nM L−1), low interference, and good stability. Detection of lower concentrations of BPA enables real sample analysis in the food industries (milk, orange juice, yogurt, tap water, and baby feeding bottles). Surprisingly, the BPA was detected in milk 510 nM L−1, orange juice 340 nM L−1, yogurt 1050 nM L−1, and tap water 140 nM L−1. Moreover, an interaction mechanism between the BPA analyte and ZnCo2O4 was discussed. [ABSTRACT FROM AUTHOR]

Published
2024
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41. Fabrication of a novel tantalum boride/vanadium carbide modified screen-printed carbon electrode for voltammetric determination of pimonidazole in bio-fluids.

Author

Rajaji, Umamaheswari, Saisree, S., Sandhya, K. Y., Alshgari, Razan A., Juang, Ruey-Shin, and Liu, Ting-Yu

Subjects
*CARBON electrodes, *VOLTAMMETRY, *X-ray crystallography technique, *TANTALUM, *VOLTAMMETRY technique, *VANADIUM, *ELECTROCHEMICAL sensors
Abstract

For the first time, a tumour hypoxia marker detection has been developed using two-dimensional layered composite modified electrodes in biological and environmental samples. The concept of TaB2 and V4C3-based MXene composite materials is not reported hitherto using ball-milling and thermal methods and it remains the potentiality of the present work. The successful formation is confirmed through various characterisation techniques like X-ray crystallography, scanning electron microscopy photoelectron, and impedance spectroscopy. A reliable and repeatable electrochemical sensor based on TaB2@V4C3/SPCE was developed for quick and extremely sensitive detection of pimonidazole by various electroanalytical methods. It has been shown that the modified electrode intensifies the reduction peak current and causes a decrease in the potential for reduction, in comparison with the bare electrode. The proposed sensor for pimonidazole reduction has strong electrocatalytic activity and high sensitivity, as demonstrated by the cyclic voltammetry approach. Under the optimal experimental circumstances, differential pulse voltammetry techniques were utilised for generating the wide linear range (0.02 to 928.51 µM) with a detection limit of 0.0072 µM. The resultant data demonstrates that TaB2@V4C3/SPCE nano-sensor exhibits excellent stability, reliability, and repeatability in the determination of pimonidazole. Additionally, the suggested sensor was successfully used to determine the presence of pimonidazole in several real samples, such as human blood serum, urine, water, and drugs. [ABSTRACT FROM AUTHOR]

Published
2024
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