Muramic acid (Mur) is present in the cell wall of Eubacteria and serves as a chemical marker for the trace detection of bacteria and bacterial cell wall debris in complex matrices. There have been numerous studies using a variety of derivatives of Mur, particularly in combination with gas chromatography-tandem mass spectrometry (GC-MS-MS) where the detection limit has been steadily lowered. A stable, halogenated derivative, the pentafluorobenzyl oxime (PFBO) acetate of Mur, has been developed by others and successfully used for GC with electron-capture detection. The current report is the first use of this derivative for GC-MS-MS analysis of Mur, or indeed any other carbohydrate, using negative ion chemical ionization (NICI) with GC-MS-MS. Mur was readily detected in settled surface dust (166 ng/mg), as well as dust collected from indoor air (1.4-5.9 ng/mg). Analyses of Mur as a PFBO acetate by GC-NICI-MS-MS or as alditol acetates by electron impact GC-electron impact ionization MS-MS serve as complementary approaches for trace detection in complex matrices.
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http://dx.doi.org/10.1016/s0021-9673(01)01537-0 | DOI Listing |
Chem Sci
December 2024
Key Laboratory of Precision and Intelligent Chemistry, University of Science and Technology of China Hefei Anhui 230026 China
The packing of organic molecular crystals is often dominated by weak non-covalent interactions, making their rearrangement under external stimuli challenging to understand. We investigate a pressure-induced single-crystal-to-single-crystal (SCSC) transformation between two polymorphs of 2,4,5-triiodo-1-imidazole using machine learning potentials. This process involves the rearrangement of halogen and hydrogen bonds combined with proton transfer within a complex solid-state system.
View Article and Find Full Text PDFSmall
January 2025
Key Laboratory of Chemical Additives for China National Light Industry, College of Chemistry and Chemical Engineering, Shaanxi University of Science and Technology, Xi'an, 710021, P. R. China.
Regulating strategies for long persistent luminescence (LPL) are always in high demand. Herein, a series of coordination polymers (CPs) (SUST-Z1-Z4) are fabricated using 1,10-phenanthroline derivatives involving different substituents (─H, ─CH, ─Cl, and ─Br) as ligands, respectively. Crystallographic data demonstrate that these CPs adopt alternating arrangements of cadmium halide chains and π-conjugated ligands.
View Article and Find Full Text PDFNat Commun
January 2025
Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore, Republic of Singapore.
Employing electrochemistry for the selective functionalization of liquid alkanes allows for sustainable and efficient production of high-value chemicals. However, the large potentials required for C(sp)-H bond functionalization and low water solubility of such alkanes make it challenging. Here we discover that a Pt/IrO electrocatalyst with optimized Cl binding energy enables selective generation of Cl free radicals for C-H chlorination of alkanes.
View Article and Find Full Text PDFJ Chem Phys
January 2025
Key Laboratory of Optoelectronic Technology and System of Ministry of Education, College of Optoelectronic Engineering, Chongqing University, Chongqing 400044, China.
Auxetic materials hold tremendous potential for many advanced applications, but candidates are quite scarce, especially at two dimensions. Here, we focus on two-dimensional (2D) metal dichalcogenides and dihalides with the chemical formula MX2 by screening structures sharing the P4̄m2 space group among 330 MX2 compounds from the computational 2D materials database. Via high-throughput first-principles computations, 25 stable MX2 (M = Mg, Ca, Mn, Co, Ni, Cu, Zn, Ge, Cd, Sn; X = F, Cl, Br, I, O, S, Se) systems with in-plane negative Poisson's ratios (NPRs) are successfully identified.
View Article and Find Full Text PDFBMC Microbiol
December 2024
School of Environment and Resource, Xichang University, Xichang, 615000, China.
The extensive mining of bastnasite (CeFCO) has caused pollution of lanthanum (La), cerium (Ce), and fuorine (F) in the surrounding farmland soil, severely threatening the safety of the soil ecosystem. However, the interaction effects of various chemical fractions of La, Ce, and F on the composition of microbial communities are unclear. In our study, high-throughput sequencing was performed based on the pot experiments of four types of combined pollution soils, i.
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