- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Simultaneous determination of ascorbic acid, dopamine, and uric acid using graphene quantum dots/ionic liquid modified screen-printed carbon electrode
摘要： In this work, graphene quantum dots (GQDs) and ionic liquid (IL) modified screen-printed carbon electrode (GQDs/IL-SPCE) were introduced for the simultaneous determination of ascorbic acid (AA), dopamine (DA) and uric acid (UA). GQDs were synthesized by directly pyrolyzing citric acid and then dropped onto the surface of IL-SPCE, which was prepared by screen-printing the mixture of IL and carbon ink on a portable substrate. UV-Vis spectrophotometry, fluorescence spectrophotometry, transmission electron microscopy (TEM), scanning electron microscopy (SEM), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) were used to characterize the synthesized GQDs and the modified electrodes. The GQDs/IL-SPCE exhibited excellent electrocatalytic activity for the oxidation of AA, DA, and UA in the mixture solution. Moreover, the anodic peak responses of these three analytes were also resolved into three well-defined peaks. Under the optimized conditions, the linear response ranges for AA, DA, and UA were 25 - 400 μM, 0.2 - 10 μM, and 0.5 - 20 μM, respectively, with low detection limits (σ/N = 3) of 6.64 μM, 0.06 μM, and 0.03 μM, respectively. The proposed sensor exhibited high sensitivity, low cost and successfully applied for the simultaneous detection of AA, DA, and UA in pharmaceutical products and biological samples.
关键词： Graphene quantum dots,Uric acid,Dopamine,Screen-printed carbon electrode,Ionic liquid,Ascorbic acid
更新于2025-09-19 17:13:59
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Characterization of Polylactide-Stabilized Gold Nanoparticles and Its Application in the Fabrication of Electrochemical DNA Biosensors
摘要： In this work, two different approaches to gold nanoparticles (AuNPs) have been explored for the modification of screen-printed electrode based on AuNPs and AuNPs stabilized with polylactic acid (PLA). The modified substrate has been characterized using UV-Vis spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM) and cyclic voltammetry. Both synthesized AuNPs were studied in terms of stability, sensitivity and reproducibility to enhance the sensing capability of modified electrodes. The PLA-stabilized AuNPs form strong structured nanoparticles and stabilize in aqueous solution. A larger active surface area (0.41 cm2) and lower charge transfer resistance (Rct) value were reported in the modification of sensing material with PLA-stabilized AuNPs, which resulted in enhancement of sensitivity. Therefore, AuNPs in PLA can be used as a potential alternative modifier for sensing chemicals and biomolecules in electrochemical sensors.
关键词： gold nanoparticles,polylactic acid,screen-printed carbon electrode,electrochemical DNA biosensor
更新于2025-09-09 09:28:46
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Renewal Mechanism of UV-Ozone-Cleaning Process on Contaminated Screen-Printed Carbon Electrodes
摘要： Screen-printed carbon electrode (SPCE) has been extensively applied in electrochemical (EC) detection due to its excellent characteristics and low cost. However, SPCE is more likely to be contaminated that seriously affects the sensitivity and reproducibility of detection. In this paper, UV-ozone-cleaning process was utilized to solve this problem. Renewal mechanism of UV-ozone-cleaning on contaminated SPCE was ?rstly investigated in detail, in which the level of SPCE contamination was represented by interfacial impedance. Both scanning electron microscopy and X-ray photoelectron spectroscopy were employed to evaluate the surface morphology and chemical constituents of SPCE respectively. The results indicate that the signi?cant EC enhancement was mainly attributed to the removal of contaminants, the increase of both reaction area and surface oxygen functional groups. To further demonstrate the renewal effect, the determination of nicotinamide adenine dinucleotide was performed. Compared with the contaminated SPCE, the UV-ozone-cleaned SPCE exhibits better EC response that the anodic peak current increased by 6～28% and the sensitivity increased from 13.31 to 19.11 μA · mM?1. Moreover, the cleaned SPCE shows good reproducibility with the low standard deviation of peak current and oxidation potential.
关键词： screen-printed carbon electrode,electrochemical detection,contamination,renewal mechanism,UV-ozone-cleaning
更新于2025-09-09 09:28:46