A detailed kinetic investigation of As(III) oxidation was performed on gold surface within pH between ∼3.0 and ∼9.0. It was found that the As(III) oxidation on the gold surface follows a purely adsorption-controlled process irrespective of pH. The evaluated adsorption equilibrium constant decreased from 3.21 × 10 to 1.61 × 10 mol L for acidic to basic medium, which implies the strong affinity of the arsenic species in the acidic medium. Besides, the estimation of Gibbs free energy revealed that an acidic medium promotes arsenic oxidation on gold surface. In mechanistic aspect, the oxidation reaction adopts a stepwise pathway for acidic medium and a concerted pathway for neutral and basic medium. From the substantial kinetic evaluation, it is established that a conducive and compatible environment for the oxidation of arsenic was found in an acidic medium rather than a basic or neutral medium on gold surface. Besides, in sensitivity concern, neutral and highly acidic medium is quite favourable for the arsenite oxidation on gold surface.
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http://dx.doi.org/10.1016/j.heliyon.2023.e14192 | DOI Listing |
Anal Methods
November 2017
Lab of Biosystem and Microanalysis, State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, China.
As an important small molecule, adenosine triphosphate (ATP) plays an important role in the regulation of cell metabolism and supplies energy for various biochemical reactions in organisms. We herein developed a sensitive surface-enhanced Raman scattering (SERS) biosensor for highly specific detection of ATP using core-satellite assemblies. To construct the aptamer-based biosensor, a known ATP binding aptamer was divided into two segments.
View Article and Find Full Text PDFAnal Methods
November 2017
Anhui Key Laboratory of Chemo-Biosensing, Key Laboratory of Functional Molecular Solids, Ministry of Education, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000, PR China.
A new aptamer-based surface plasmon resonance (SPR) system has been designed to detect Hg that utilizes near-infrared (NIR)-to-NIR gold nanoparticle coated NaYF:Yb,Tm,Gd up-conversion nanoparticles (AuNPs@NaYF:Yb,Tm,Gd UCNPs) as probes. The AuNPs@NaYF:Yb,Tm,Gd UCNPs were prepared and excited by near-infrared light (980 nm) which emitted at a near-infrared wavelength (808 nm) using an inexpensive infrared continuous wave laser diode. The AuNPs@NaYF:Yb,Tm,Gd UCNPs were conjugated with Hg aptamers.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Philipps-Universität Marburg, Fachbereich Chemie, Hans-Meerwein-Str. 4, 35032 Marburg, Germany.
Acenes are an important class of polycyclic aromatic hydrocarbons that have gained considerable attention from chemists, physicists, and material scientists, due to their exceptional potential for organic electronics. They serve as an ideal platform for studying the physical and chemical properties of sp carbon frameworks in the one-dimensional limit and also provide a fertile playground to explore magnetism in graphenic nanostructures due to their zigzag edge topology. While higher acenes up to tridecacene have been successfully generated by means of on-surface synthesis, it is imperative to extend their synthesis toward even longer homologues to comprehensively understand the evolution of their electronic ground state.
View Article and Find Full Text PDFOcul Surf
January 2025
Department of Ophthalmology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences; Key Laboratory of Ocular Fundus Diseases, Chinese Academy of Medical Sciences. Electronic address:
Unlabelled: Dry eye disease is a multifactorial disorder of the ocular surface with increasing global prevalence, yet no universally accepted "gold standard" exists for its diagnosis or severity assessment. Tear matrix metalloproteinase 9 (MMP-9) is widely recognized as a valuable biomarker for dry eye, yet there remains a critical need for a simple, accurate, and broadly applicable method for its quantification. This study aims to develop and evaluate a Schirmer strip-based Eu-time resolved fluorescence immunochromatography (Eu-TRFICO) method for the quantitative detection of MMP-9 in tears.
View Article and Find Full Text PDFPLoS One
January 2025
Faculty of Science and Engineering, Waseda University, Tokyo, Japan.
Gold (or electrum) in hydrothermal fluid precipitates directly from gold sulfide complex and/or partly via suspended nanoparticles. The hydrothermal fluid contains "invisible gold" that is atomically dispersed in sulfide minerals or as nanoparticles with a size of less than 10 nm. However, the contribution of these gold nanoparticles to the formation of native gold and its alloy with silver (electrum) remains unclear.
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