The chemical changes occurring in the phenol-formaldehyde resins (resol and novolac type) during their storage were investigated. In this paper the FT-IR, py-GCMS and inverse gas chromatography methods were applied for assessment of the changes occurring during storage of the phenolic resins. We have found that during storage some examined resins occurred partial curing. The results from all techniques applied are consistent. Py-GCMS is useful technique for screening the storage processes but IGC seems to be most sensitive one.
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http://dx.doi.org/10.1016/j.chroma.2014.07.045 | DOI Listing |
J Biomater Sci Polym Ed
January 2025
Novel Drug Delivery Systems Laboratory, Faculty of Pharmacy, Medical Sciences/University of Tehran, Tehran, Iran.
Analyzing the chemical composition of different kinds of acrylic cement is necessary to understand their properties and suitability for curing bone defects. Conducting various chemical tests can give valuable insight into the composition, viscosity, and performance characteristics of each kind of cement, Therefore, our study aimed to find safety standards and the effectiveness of these products for medical applications. The polymeric characterization was determined by Nuclear Magnetic Resonance (H-NMR) spectroscopy and Fourier-transform infrared spectroscopy (FTIR).
View Article and Find Full Text PDFSci Total Environ
January 2025
Social Development and Health Promotion Research Center, Health Policy and Promotion Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran. Electronic address:
Nowadays, polyethylene terephthalate (PET) bottles are widely used for packaging drinks and food. However, concerns have been raised about the possible migration of harmful chemicals, particularly phthalates, from these containers into their contents. Therefore, this study investigates the effects of sunlight exposure and PET bottle reuse on phthalate migration, focusing on three common phthalates: bis(2-ethylhexyl) phthalate (DEHP), dibutyl phthalate (DBP), and benzyl butyl phthalate (BBP).
View Article and Find Full Text PDFMethods Mol Biol
January 2025
Laboratory of Analytical Biochemistry & Metabolomics, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic.
A simple analytical workflow is described for gas chromatographic-mass spectrometric (GC-MS)-based chiral profiling of secondary amino acids (AAs) in biological matrices. The sample preparation is carried out directly in aqueous biological sample extracts and involves in situ heptafluorobutyl chloroformate (HFBCF) derivatization-liquid-liquid microextraction of nonpolar products into hexane phase followed by subsequent formation of the corresponding methylamides from the HFB esters by direct treatment with methylamine reagent solution. The (O, N) HFB-butoxycarbonyl-methylamide AA products (HFBOC-MA) are separated on a Chirasil-L-Val capillary column and quantitatively measured by GC-MS operated in selected ion monitoring (SIM) mode.
View Article and Find Full Text PDFArch Toxicol
January 2025
STARTNETICS - Department of Chemical Science and Technologies, University of Rome Tor Vergata, Via della Ricerca Scientifica 1, 00133, Rome, Italy.
Femtosecond lasers represent a novel tool for tattoo removal as sources that can be operated at high power, potentially leading to different removal pathways and products. Consequently, the potential toxicity of its application also needs to be evaluated. In this framework, we present a comparative study of Ti:Sapphire femtosecond laser irradiation, as a function of laser power and exposure time, on water dispersions of Pigment Green 7 (PG7) and the green tattoo ink Green Concentrate (GC), which contains PG7 as its coloring agent.
View Article and Find Full Text PDFJ Food Sci
January 2025
Spice and Beverage Research Institute, Chinese Academy of Tropical Agricultural Sciences, Wanning, China.
Fermentation is crucial for inducing desirable flavor and aroma profiles in cocoa products. This research focused on identifying microbial strains isolated from spontaneous cocoa fermentation in Hainan through 16S and Internal Transcribed Spacer (ITS) sequencing. Pectinase activity was screened, and metabolic dynamics of sugars and organic acids were analyzed using high-performance liquid chromatography.
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