The aim of the present work is to propose a method for the determination of ibuprofen, as a typical representative of pharmaceutical compounds, in aqueous samples. To do so, an in situ derivatization reaction in aqueous medium was employed in the vial of a headspace sampler (HS), after which instrumental measurements were made with gas chromatography-mass spectrometry (GC-MS). As the injection system we propose a programmed temperature vaporizer (PTV) where, in solvent vent mode, better results can be obtained than with the conventional split and splitless injection modes. Since the derivatization reaction takes place in the HS vial, after the mixing of reagents and the sealing of the vial, the whole process takes place on-line, with no need for intermediate steps. The simplicity and speed of the method--analysis throughput: 10.5 min--together with the limit of detection obtained (0.23 microg/L), bearing in mind that no preconcentration step or later clean-up step are required, make this a good method for the analysis of ibuprofen in aqueous samples of urban waste water.
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http://dx.doi.org/10.1016/j.chroma.2009.08.011 | DOI Listing |
J Nat Prod
December 2024
Key Laboratory of Chemistry in Ethnic Medicinal Resources, Ministry of Education of China, School of Ethnomedicine and Ethnopharmacy, Yunnan Minzu University, Kunming 650504, People's Republic of China.
Six undescribed macrocyclic compounds, including diarylhexanoids ( and ), a diarylhexanoid glucoside (), diarylheptanoids ( and ), and an aceroside (), were isolated from the roots of Cheval., along with 11 known analogues (-). The structures were elucidated by spectroscopic analysis, as well as by calculated optical rotatory dispersion and derivatization reactions.
View Article and Find Full Text PDFJ Agric Food Chem
December 2024
Qualisud, Université Montpellier, CIRAD, Montpellier SupAgro, Université d'Avignon, Université de La Réunion, Montpellier 34093, France.
Phytate in plants (inositol phosphates, InsPs) affects mineral bioavailability. However, methods for their quantification may lead to variable results, and some are nonspecific (spectrophotometric techniques). In this study, ion-pair high-performance liquid chromatography (HPLC) was coupled with post-column derivatization to allow fluorescence detection (FLD, λ324/λ364 nm) of InsPs.
View Article and Find Full Text PDFOrg Lett
December 2024
Jiangsu Provincial Key Lab for the Chemistry and Utilization of Agro-Forest Biomass, Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Jiangsu Key Lab of Biomass-Based Green Fuels and Chemicals, International Innovation Center for Forest Chemicals and Materials, College of Chemical Engineering, Nanjing Forestry University, Nanjing, Jiangsu 210037, China.
We herein report the efficient synthesis of peptide-benzazepine conjugates from Lys-based peptides and acroleins via Rh(III)-catalyzed double C-H activation. This reaction features mild reaction conditions, broad scope, high atom and step economies, and excellent chemo- and site selectivity. The synthetic utility of this strategy is further demonstrated by scale-up experiments and product derivatizations, including diverse late-stage ligations based on the aldehyde moiety.
View Article and Find Full Text PDFCold Spring Harb Protoc
December 2024
Christopher S. Bond Life Sciences Center, Division of Biological Sciences, Interdisciplinary Plant Group, University of Missouri, Columbia, Missouri 65211, USA
Amino acid analysis is a vital part of analytical biochemistry. The increasing demand for low nitrogen fertilization and for plant-based diets with balanced amino acid levels and composition have made it crucial to develop reliable, fast, and affordable methods for analyzing amino acids in plants. As maize accounts for 43% of global cereal production, improving the amino acid composition of its kernels (i.
View Article and Find Full Text PDFOrg Lett
December 2024
National Engineering Research Center for Carbohydrate Synthesis, Jiangxi Normal University, Nanchang 330022, China.
We have developed a glycosyl radical-based synthesis of -alkyl glycosides through a deoxygenative Giese addition-reduction-cyclization cascade, in which readily available 1-hydroxy carbohydrates serve as precursors for glycosyl radicals and aryl alkenes function as radical acceptors. This reaction not only provides an effective method for accessing a previously underexplored class of functionalized cyclopropanes but also enhances the application of Giese addition in the synthesis of -alkyl glycosides by derivatizing the radical intermediate generated through polar cyclization to yield a cyclopropane.
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