Here, we report on sequential solid-phase extraction of leonardite hymatomelanic acid (CHM) on a non-ionic sorbent at four steadily lowered pH values: 7, 5, 3, and 2, yielding fractions with different acidic properties. Using nuclear magnetic resonance (NMR) spectroscopy and ultrahigh-resolution mass spectrometry, we revealed a gradual shift of dominating scaffolds in the fractions of CHM from reduced saturated to oxidized aromatic compounds. An increase on the average aromaticity of the CHM fractions was accompanied by a red shift in fluorescence spectra. These results were supported by heteronuclear single quantum coherence and heteronuclear multiple bond correlation NMR experiments. We have demonstrated that the CHM fraction isolated at pH 5 was dominated by aliphatic carboxyl carriers, while the pH 3 fraction was dominated by aromatic carboxyl acids. The developed fractionation technique will enable deeper insight on structure-property relationships and the design of the humic-based materials with tailored reactive properties.
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http://dx.doi.org/10.1021/acs.jafc.8b04079 | DOI Listing |
Small Methods
January 2025
BCMaterials, Basque Centre for Materials, Applications and Nanostructures; UPV/EHU Science Park, Leioa, 48940, Spain.
Carbon coating on SiO surface is crucial for enhancing initial Coulombic efficiency (ICE) and cycling performance in batteries, while also buffering volume expansion. Despite its market prevalence, the effects of the carbon layer's quality and structure on the electrochemical properties of SiO remain underexplored. This study compares carbon layers produced via gas-phase and solid-phase coating methods, introducing an innovative technique that sequentially uses two gases to develop a low-impedance hybrid carbon structure.
View Article and Find Full Text PDFAnal Chim Acta
January 2025
Department of Chemistry, National Chung Hsing University, Taichung City, 402202, Taiwan, ROC. Electronic address:
Background: To integrate valves, manifolds, and solid-phase extraction (SPE) columns into a compact device is technically difficult. Four-dimensional printing (4DP) technologies, employing stimuli-responsive materials in three-dimensional printing (3DP), are revolutionizing the fabrication, functionality, and applicability of stimuli-responsive analytical devices that can show time-dependent shape programming to enable more complex geometric designs and functions. However, 4D-printed stimuli-responsive actuators and valves utilized to control flowing streams in SPE applications remain rare.
View Article and Find Full Text PDFMolecules
December 2024
Department of Analytical Chemistry, Institute of Chemistry, Faculty of Science, Pavol Jozef Safarik University in Kosice, Moyzesova 11, 040 01 Kosice, Slovakia.
Industrialization has led to environmental pollution with various hazardous chemicals including pollution with metals. In this regard, the development of highly efficient analytical methods for their determination has received considerable attention to ensure public safety. Currently, scientists are paying more and more attention to the automation of analytical methods, since it permits fast, accurate, and sensitive analysis with minimal exposure of analysts to hazardous substances.
View Article and Find Full Text PDFAnal Chem
December 2024
School of Biological Science & Medical Engineering, Southeast University, Nanjing 210096, China.
Extracellular vesicles (EVs) offer promising noninvasive alternatives for convenient and noninvasive prostate cancer (PCa) diagnosis, but inefficient EV enrichment and cargo extraction hinder discovery and validation for their clinical applications. Here, we present an integrated pipeline based on functionalized magnetic beads to streamline and enhance the efficiency of urinary EV miRNA analysis. EVs are first enriched on amphiphilic magnetic beads through chemical affinity, followed by EV lysis and the isolation of miRNAs through solid phase extraction.
View Article and Find Full Text PDFReprod Biomed Online
August 2024
BRGM, Orléans, France.
Research Question: Are bisphenols released from disposable devices used in assisted reproductive technology (ART) procedures, and do they accumulate when several disposable devices are used sequentially under routine conditions?
Design: A comprehensive assessment of 19 individual disposable devices (31 assessments) and nine combinations of disposable devices replicating the main steps in an ART procedure was undertaken. The extraction of bisphenols followed routine-use conditions (temperature and duration). The concentrations of 10 bisphenols were determined using online solid-phase extraction/liquid chromatography/mass spectrometry methodology.
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