Currently, dissolved nitrogenous organic matters in water, important precursors of disinfection by-products (DBPs), are of significant concern. This study was to explore the formation of chloroform (CF) during chlorination of alanine (Ala), an important nitrogenous organic compound commonly present in water sources. Our results indicated that the CF yield reached a maximum value of 0.143% at the molar ratio of chlorine atom to nitrogen atom (Cl/N)=1.0 over a Cl/N range of 0.2-5.0 (pH=7.0, reaction time=5d, and initial Ala=0.1mM). At an acidic-neutral condition (pH 4-7), the formation of CF was suppressed. However, the highest CF yield (0.227%) occurred at weakly alkaline condition (pH 8.0) (initial Ala=0.1mM, and Cl/N=1.0). The increase of Br(-) in water can increase total trihalomethanes (THMs) and bromo-THMs. However, the bromo-THMs level reached a plateau at Br(-)/Cl>0.04. Finally, based on the computation of frontier electron density and identification and measurement of key intermediates during Ala chlorination, we proposed a formation pathway of CF from Ala chlorination: Ala-->monochloro-N-alanine (MC-N-Ala)-->acetaldehyde (AAld)-->monochloroacetaldehyde acetaldehyde (MCAld)-->dichloroacetaldehyde (DCAld)-->trichloroacetaldehyde (TCAld)-->CF.
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http://dx.doi.org/10.1016/j.chemosphere.2009.09.030 | DOI Listing |
Magn Reson Chem
January 2025
Laboratório de Química Computacional e Modelagem Molecular (LQC-MM), Departamento de Química Inorgânica, Instituto de Química, Universidade Federal Fluminense (UFF), Niterói, Rio de Janeiro, Brazil.
We present a DFT-PCM NMR study of 3-indoleacetic acid (3-IAA), used as a working example, including explicit solvent molecules, named PCM-nCHCl, PCM-nDMSO (n = 0, 2, 4, 8, 14, 20, and 25), to investigate the dimer formation in solution. Apart from well-known cyclic (I) and open (II) acetic acid (AA) dimers, two new structures were located on DFT-PCM potential energy surface (PES) for 3-IAA named quasicyclic A (III) and quasicyclic B (IV), the last one having N-H…O hydrogen bond (instead of O-H…O). In addition, four other structures having π-π type interactions named V, VI, VII, and VIII were also obtained completing the sample on the PES.
View Article and Find Full Text PDFPathogens
December 2024
Department of Inorganic and Analytical Chemistry, Faculty of Chemistry, Rzeszów University of Technology, Powstańców Warszawy 6, 35-959 Rzeszów, Poland.
and are challenging to differentiate using methods such as phenotyping, 16S rRNA sequencing, or protein profiling through matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) due to their close relatedness. This study explores the potential for identifying and by incorporating reference spectra of metabolite profiles, obtained via surface-assisted laser desorption/ionization mass spectrometry (SALDI MS) employing gold nanoparticles (AuNPs), into the Bruker Biotyper database. Metabolite extracts from and cells were prepared using liquid-liquid extraction in a chloroform-methanol-water system.
View Article and Find Full Text PDFMicroorganisms
January 2025
Key Laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), College of Life Sciences/Institute of Agro-Bioengineering, Guizhou University, Guiyang 550025, China.
As a food packaging sliding agent, erucamide is widely used in the field of food packaging, but the traditional synthesis method of erucamide faces the problems of insufficient raw materials and low yield of colza oil. Our laboratory has found that L2 has the potential to produce erucamide. This study aims to improve the ability of L2 to produce erucamide by adding various accelerants to optimize the fermentation conditions.
View Article and Find Full Text PDFToxics
January 2025
School of Public Health, MOE Key Laboratory of Geriatric Diseases and Immunology Suzhou Medical College, Soochow University, Suzhou 215123, China.
The control of waterborne diseases through water disinfection is a significant advancement in public health. However, the disinfection process generates disinfection by-products (DBPs), including trihalomethanes (THMs), which are considered to influence the occurrence of cancer. This analysis aims to quantitatively evaluate the relationship between blood concentrations of THMs and cancer.
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State Key Laboratory for Quality Ensurance and Sustainable Use of Dao Di Herbs, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100193, China.
This study investigated the protective effect of Dai Bai Jie (DBJ) extract against acute alcoholic liver injury (AALI) and elucidated its potential mechanism. The total saponin level in the DBJ extracts was measured using vanillin-chloroform acid colorimetry. To observe the preventive and protective effects of DBJ on AML-12 cells in an ethanol environment, the effective components of DBJ were identified.
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