The aza-Michael addition and the Mannich condensation occur in thin films deposited on ambient surfaces. The reagents for both C-N bond formation reactions were transferred onto the surface by drop-casting using a micropipette. The surface reactions were found to be much more efficient than the corresponding bulk solution-phase reactions performed on the same scale in the same acetonitrile solvent. The increase in rate of product formation in the thin film is attributed to solvent evaporation in the open air which results in reagent concentration and produces rate acceleration similar to that seen in evaporating droplets in desorption electrospray ionization. This thin film procedure has potential for the rapid synthesis of reaction products on a small scale, as well as allowing rapid derivatization of analytes to produce forms that are easily ionized by electrospray ionization. Analysis of the derivatized sample directly from the reaction surface through the use of desorption electrospray ionization is also demonstrated.
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http://dx.doi.org/10.1007/s13361-012-0394-y | DOI Listing |
J Chromatogr B Analyt Technol Biomed Life Sci
December 2024
Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa. Electronic address:
A robust LC-MS/MS method was developed to quantify total and unbound doravirine in plasma samples from patients receiving daily doses of 100 mg doravirine, in combination with lamivudine and tenofovir disoproxil fumarate, in a phase 3 clinical trial. The trial is ongoing, and sample analysis is planned to commence once all samples have been collected. The method was validated to quantify both total and unbound doravirine using a single calibration curve.
View Article and Find Full Text PDFInorg Chem
January 2025
Department of Chemistry, Western Michigan University, Kalamazoo, Michigan 49008, United States.
The supramolecular binding exclusively by H-bonds of SeO, MoO and WO ions to form nanojars of the formula [EO⊂{-Cu(μ-OH)(μ-pz)}] (; E = Se, Mo, W; = 28-34; pz = pyrazolate) was studied in solution by electrospray ionization mass spectrometry, variable temperature, paramagnetic H NMR and UV-vis spectroscopy, and in the solid state by single-crystal X-ray crystallography. These large anions allow for the observation of a record nanojar size, (E = Mo, W). Six crystal structures are described of nanojars of varying sizes with either SeO, MoO or WO entrapped ions, including the first example of a cocrystal of two different nanojars in crystallographically unique positions, and .
View Article and Find Full Text PDFBiomed Chromatogr
February 2025
Department of Pharmacy, Xuzhou Central Hospital, Xuzhou, China.
Ginkgolide B (GB) is the main active ginkgolide in Ginkgo biloba leaves extract. Pharmacological study suggested that GB exhibits protective effect on nervous system impaired and can be used in the treatment of dementia, cerebral insufficiency or related cognitive decline. However, the information on pharmacokinetics of GB in vivo was limited.
View Article and Find Full Text PDFJ Agric Food Chem
January 2025
Gulbali Institute, Charles Sturt University, Wagga Wagga, New South Wales 2678, Australia.
infections of grapes significantly reduce yield and quality and increase phenolic compound oxidation, resulting in color loss, off-flavors, and odors in wine. In this study, metabolites were extracted from grape homogenates comprising healthy or infected grapes from different vintages, cultivars, regions, and maturity stages. Samples were randomly analyzed by direct injection into an ion trap mass spectrometer, with data collected from 50 to 2000 / for 1 min.
View Article and Find Full Text PDFAnal Methods
January 2025
State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing 210023, China.
Dichloroacetic acid (DCAA), trichloroacetic acid (TCAA), and bromate (BrO) are disinfection byproducts (DBPs) formed during drinking water treatment and pose health risks. Rapid and reliable detection of these DBPs is essential for ensuring water safety. Non-suppressed ion chromatography (IC)-electrospray ionization mass spectrometry (IC-ESI-MS/MS) offers a promising approach for simultaneous analysis of organic haloacetic acids (HAAs) and inorganic oxyhalides, but previous methods using toxic methylamine can pose health risks.
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