We present a novel method for the quantitative analysis of mixtures of semivolatile chemical compounds. For the first time, thermal desorption is integrated directly with nanoelectromechanical infrared spectroscopy (NEMS-IR-TD). In this new technique, an analyte mixture is deposited via nebulization on the surface of a NEMS sensor and subsequently desorbed using heating under vacuum. The desorption process is monitored via infrared spectroscopy and thermogravimetric analysis. The resulting spectro-temporal maps allow for selective identification and analysis of the mixture. In addition, the corresponding thermogravimetric data allow for analysis of the desorption dynamics of the mixture components. As a demonstration, caffeine and theobromine were selectively identified and quantified from a mixture with a detection limit of less than 6 pg (about 30 fmol). With its exceptional sensitivity, NEMS-IR-TD allows for the analysis of low abundance and complex analytes with potential applications ranging from environmental sensing to life sciences.
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http://dx.doi.org/10.1021/acssensors.2c02435 | DOI Listing |
Dye-laden wastewater poses a significant environmental and health threat. This study investigated the potential of green-synthesized zinc oxide nanoparticles (ZnO NPs), derived from Padina pavonica brown algae extract, for the removal of methylene blue (MB) dye. The hypothesis was that utilizing algal extract for ZnO NP synthesis would enhance adsorption capacity and photocatalytic activity for dye removal.
View Article and Find Full Text PDFInt J Biol Macromol
December 2024
School of Mechanical Engineering, Jiangnan University, Wuxi, Jiangsu 214122, China; Jiangsu Key Laboratory of Advanced Food Manufacturing Equipment Technology, Jiangnan University, Wuxi, Jiangsu 214122, China.
The antioxidant activity of ε-polylysine (EPL) can be enhanced by grafting phenolic compound caffeic acid (CA) onto its amino groups. To enhance the antioxidant activity of EPL, this study synthesized caffeic acid-ε-polylysine conjugate (CA-EPL) by grafting CA onto EPL using carbodiimide coupling reaction. Fourier transform infrared spectroscopy, H nuclear magnetic resonance (NMR) spectroscopy confirmed the successful conjugation of caffeic acid and ε-polylysine.
View Article and Find Full Text PDFWater Res
December 2024
Soil Chemistry and Chemical Soil Quality Group, Wageningen University & Research, PO BOX 47, Wageningen 6700 AA, the Netherlands.
Binding of glyphosate (PMG) to metal (hydr)oxides controls its availability and mobility in natural waters and soils, and these minerals are often suggested for the removal of PMG from wastewaters. However, a solid mechanistic and quantitative description of the adsorption behavior and surface speciation on these surfaces is still lacking, while it is essential for understanding PMG behavior in aquatic and terrestrial systems. This study gives new insights through advanced surface complexation modeling of new and previously published adsorption data, supplemented with MO/DFT calculations of the geometry, thermochemistry and theoretical infrared (IR) spectra of the surface complexes.
View Article and Find Full Text PDFJ Contam Hydrol
December 2024
Division of Earth and Environmental System Sciences-Major of Environmental Geosciences, Pukyong National University, Busan 48513, South Korea; Wible Co Ltd, Pukyong National University, 365 Sinseon-ro, Nam-gu, Busan 48547, South Korea. Electronic address:
Microplastics (MPs) in aquatic environments adsorb heavy metals, thereby posing potential environmental risks. However, further research is needed to elucidate the adsorption behavior of different types of MPs for various heavy metals. The aim of this study was to characterize four types of MPs: polypropylene (PP), polyvinyl chloride (PVC), high-density polyethylene (HDPE), and low-density polyethylene (LDPE).
View Article and Find Full Text PDFDev Sci
March 2025
Division of Developmental Medicine, Department of Pediatrics, Boston Children's Hospital, Boston, Massachusetts, USA.
Functional magnetic resonance imaging (fMRI) studies with adults provide evidence that functional brain networks, including the default mode network and frontoparietal network, underlie executive functioning (EF). However, given the challenges of using fMRI with infants and young children, little work has assessed the developmental trajectories of these networks or their associations with EF at key developmental stages. More recently, functional near-infrared spectroscopy (fNIRS) has emerged as a promising neuroimaging tool which can provide information on cortical functional networks and can be more easily implemented with young children.
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