Previous investigations have evaluated the efficacy of anions such as NO, Cl Br, CHCOO, and CFCOO as additives to generate or enhance mass spectrometric signals from explosives under plasma ionization conditions. The results of this study demonstrate that for detecting nitramine-class explosives, such as 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) and 1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane (HMX), 1,4-benzoquinone (BQ) is a highly effective and efficient dopant. When used in conjunction with ambient-pressure negative-ion helium-plasma ionization (HePI), 1,4-benzoquinone readily captures an electron, forming an abundant molecular anion (m/z 108), which upon exposure to vapors of RDX and HMX generates adduct ions of m/z 330 and 404, respectively. The signal level recorded for RDX upon adduction to the radical anion of 1,4-benzoquinone under our experimental conditions was significantly higher than that realized by chloride adduction using dichloromethane (DCM) as the dopant.
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http://dx.doi.org/10.1007/s13361-019-02339-8 | DOI Listing |
Anal Chem
January 2025
Center for Translational Biomedical Research, University of North Carolina at Greensboro, Kannapolis, North Carolina 28081, United States.
Double bond (C═C) position isomerism in unsaturated lipids can indicate abnormal lipid metabolism and pathological conditions. Novel chemical derivatization and mass spectrometry-based techniques are under continuing development to provide more accurate elucidation of lipid structure in finer structural detail. Here, we introduce a new ion chemistry for annotating lipid C═C positions, which is highly efficient for liquid chromatography-mass spectrometry-based lipidomics.
View Article and Find Full Text PDFCurr Med Chem
January 2025
Laboratory of Pharmaceutical Biotechnology and Bioinformatics, Department of Genetic Engineering and Biotechnology, Jashore University of Science and Technology, Jashore, 7408, Bangladesh.
Background: Breast cancer is a frequently diagnosed malignant disease and the primary cause of mortality among women with cancer worldwide. The therapy options are influenced by the molecular subtype due to the intricate nature of the condition, which consists of various subtypes. By focusing on the activation of receptors, Epidermal Growth Factor Receptor (EGFR) tyrosine kinase can be utilized as an effective drug target for therapeutic purposes of breast cancer.
View Article and Find Full Text PDFEndocr Metab Immune Disord Drug Targets
January 2025
Department of Rheumatology and Immunology, The First Affiliated Hospital of Army Medical University, Chongqing, China.
Background: Diabetes and osteoporosis, as chronic diseases with high incidence, have caused deep concern in the field of global public health due to their high morbidity and mortality. More importantly, the complex and close relationship between diabetes and osteoporosis has gradually become the focus of scientific research. It is very meaningful to carry out bibliometric analysis in the research field of diabetes and osteoporosis to describe the current international trend and present a visual representation of the past and emerging trends of diabetes and osteoporosis in the past decade.
View Article and Find Full Text PDFJ Chem Theory Comput
January 2025
Department of Chemistry, Rice University, Houston, Texas 77005-1892, United States.
Generalized Hartree-Fock (GHF) is a long-established electronic structure method that can lower the energy (compared to spin-restricted variants) by breaking physical wave function symmetries, namely and . After an exposition of GHF theory, we assess the use of GHF trial wave functions in phaseless auxiliary field quantum Monte Carlo (ph-AFQMC-G) calculations of strongly correlated molecular systems including symmetrically stretched hydrogen rings, carbon dioxide, and dioxygen. Imaginary time propagation is able to restore symmetry and yields energies of comparable or better accuracy than CCSD(T) with unrestricted HF and GHF references, and consistently smooth dissociation curves─a remarkable result given the relative scalability of ph-AFQMC-G to larger system sizes.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
School of Rare Earths, University of Science and Technology of China, Hefei 230026, China.
Achieving ultrahigh permeance and superoleophobicity is crucial for membrane application. Here, we demonstrated that a poly(ionic liquid)/PES hydrogel membrane can achieve dual goals. The high polarity of the ionic liquids induces the water molecules on the membrane surface to be arranged more ordered, as verified by molecular dynamics (MD) simulation and advanced femtosecond sum frequency generation (SFG) vibrational spectroscopy.
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