A chemically modified electrode based on a chitosan-multiwall carbon nanotube (MWNT) coated glassy carbon electrode (GCE) is described, which exhibits an attractive ability to determine dopamine (DA) and ascorbic acid (AA) simultaneously. The modified electrode exhibited a high differential pulse voltammetry (DPV) current response to DA at 0.144 V and AA at -0.029 V (vs. SCE) in a 0.1 mol l(-1) phosphate buffer solution (pH = 7.2). The properties and behaviors of the chitosan-multiwall carbon nanotube modified electrode (MC/GCE) were characterized using cyclic voltammetry (CV) and DPV methods. The mechanism for the discrimination of dopamine from ascorbic acid at MC/GCE is discussed. The linear calibration range for DA and AA were 5 x 10(-7) mol l(-1) to 1 x 10(-4) mol l(-1) (r = 0.997), and 5 x 10(-6) mol l(-1) to 1 x 10(-3) mol l(-1) (r = 0.996), respectively. The MC/GCE showed good sensitivity, selectivity and stability.
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http://dx.doi.org/10.2116/analsci.20.1055 | DOI Listing |
J Pharm Biomed Anal
March 2025
Department of Chemistry, Pontifical Catholic University of Rio de Janeiro (PUC-Rio), Rio de Janeiro, Brazil. Electronic address:
A luminescence-based method was developed to detect gentamicin using silver nanoparticles (AgNPs) associated with nitrogen-doped graphene quantum dots (N-GQDs). When gentamicin sulfate interacts with the AgNPs/N-GQDs system, the characteristic blue fluorescence of N-GQDs, which had been previously turned off by AgNPs, is restored. Under specific conditions (such as the amount of synthesis dispersion and pH), this AgNPs/N-GQDs probe enabled quantification of gentamicin ranging from 3.
View Article and Find Full Text PDFNanoscale
March 2025
School of Physics and Optoelectronics, South China University of Technology, Guangzhou 510640, China.
Raman spectroscopy has demonstrated significant potential in molecular detection, analysis, and identification, particularly when it adopts single-molecule surface-enhanced Raman scattering (SM-SERS) substrates. A recent SM-SERS scheme incorporates two-fold Raman enhancement mechanisms: the electromagnetic enhancement enabled by a plasmonic nanogap hotspot formed from gold sphere nanoparticles sitting on a gold mirror and the chemical enhancement enabled by a two-dimensional material, WS, inserted into the nanogap. In this work we integrate multiple advanced concepts and techniques to achieve remarkable performance improvements of SM-SERS.
View Article and Find Full Text PDFJ Fluoresc
March 2025
College of Chemistry and Molecular Science, Henan University, Kaifeng, Henan, 475004, China.
Three novel coumarin-based arylpyrazolines were successfully designed and synthesized. Among them, probe B demonstrated excellent detection capabilities for Cu. According to the fluorescence titration and Job's plot, B could form a complex with Cu in a 2∶1 ratio, the detection limit was 1.
View Article and Find Full Text PDFRSC Adv
March 2025
State Key Laboratory of Chemical Engineering, School of Chemistry & Molecular Engineering, East China University of Science and Technology Shanghai 200237 P. R. China
In this work, 5,5'-(propane-1,3-diyl)bis-(1,3,5-triazinane-2-thione) (PBT) was successfully prepared by a three-component condensation method using thiourea, formaldehyde and 1,3-diaminopropane. The inhibition properties of PBT in 1.0 mol per L HCl were investigated by gravimetric measurement, electrochemical analysis, surface analysis and quantum chemical methods.
View Article and Find Full Text PDFInt J Biol Macromol
March 2025
School of Food Sciences and Engineering, Changchun University, Changchun 130024, China. Electronic address:
In this study, the inhibitory effects of ten protopanaxadiol (PPD)-type ginsenosides on α-glucosidase in vitro were firstly investigated, and selected four ginsenosides with stronger inhibitory effects, namely CY, C-Mc, F2 and CK. The kinetic results of enzyme inhibition indicated that CY, C-Mc, F2 and CK were all non-competitive inhibitors of α-glucosidase. Fluorescence quenching and circular dichroism (CD) analyses showed that the inhibition of α-glucosidase by CY, C-Mc, F2, and CK was a static process, and that they altered the structure of α-glucosidase.
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