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high performance liquidchromatography, etc ; acetaldehyde; acrolein; emissions factor; formaldehyde; smog pollution; tillage; China; Show all 8 Subjects
Abstract:
... Emissions of carbonyl compounds from agricultural machines cannot be ignored. Carbonyl compounds can cause the formation of ozone (O₃) and secondary organic aerosols, which can cause photochemical smog to form. In this study, 20 agricultural machines were tested using portable emission measurement system (PEMS) under real-world tillage processes. The exhaust gases were sampled using 2,4-dinitrophe ...
comprehensive two-dimensional liquidchromatography; liquidchromatography, etc ; separation; solvents; Show all 4 Subjects
Abstract:
... On‐line comprehensive two‐dimensional liquid chromatography is a powerful technique for the separation of highly complex samples. Due to the addition of the second dimension of separation, impressive peak capacities can be obtained within a reasonable analysis time compared to one‐dimensional liquid chromatography. In online comprehensive two‐dimensional liquid chromatography, the separation power ...
comprehensive two-dimensional liquidchromatography; reversed-phase liquidchromatography, etc ; cation exchange chromatography; mass spectrometry; thermal stress; Show all 5 Subjects
Abstract:
... This study details the development of on-line two-dimensional liquid chromatography (2D-LC) methods combining cation-exchange chromatography (CEX) and reversed-phase liquid chromatography (RPLC) for the separation of the charge variants of a lysine-linked antibody-drug conjugate (ADC). This combination gives an excellent example of the potential benefits of 2D-LC approaches for the analysis of suc ...
liquidchromatography, etc ; prediction; temperature; viability; Show all 4 Subjects
Abstract:
... The prediction of chromatographic retention under supercritical-fluid chromatography (SFC) conditions was studied, using established and novel theoretical models over ranges of modifier content, pressure and temperature. Whereas retention models used for liquid chromatography often only consider the modifier fraction, retention in SFC depends much more strongly on pressure and temperature. The via ...
liquidchromatography, etc ; molecular dynamics; spectroscopy; Show all 3 Subjects
Abstract:
... Molecular shape can provide a basis for chromatographic separations that is distinct from other interaction mechanisms often considered in liquid chromatography. Molecular shape recognition, or shape selectivity, is most evident for the separation of isomeric compounds that have constrained molecular structures, such as polycyclic aromatic hydrocarbons. A central feature of shape-selective columns ...
high performance liquidchromatography; ultra-performance liquidchromatography, etc ; alkaloids; amphetamine; analytical chemistry; illicit drugs; tetrahydrocannabinol; youth; Egypt; Show all 9 Subjects
Abstract:
... Background: ‘Voodoo’ is a new substance of abuse that recently spread among youth in Egypt. It has numerous potentially dangerous effects on humans. However, to date the composition of the main constituents of this compound is unknown. Purpose: We sought to identify the active components of this unknown substance”voodoo”. Methods: Three samples were collected and analysed by high-performance liqui ...
liquidchromatography, etc ; mass spectrometry; metabolism; metabolites; prototypes; Show all 5 Subjects
Abstract:
... In this study, a liquid chromatography-tandem multi-stage mass spectrometry (LC/MSⁿ) method was established to characterize the metabolites of TRG in monkeys and dogs. A total of seven metabolites of TRG besides the prototype were found, which were identified as TR (M1), TRN (M2), trans-resveratrol-4'-O-glucuronide (M2'), trans-resveratrol-3-O-glucoside-4'-O-glucuronide (M3), trans-resveratrol-3-O ...
liquidchromatography, etc ; metabolites; solvents; tandem mass spectrometry; Show all 4 Subjects
Abstract:
... The comprehensive chemical characterization of biological samples remains a central challenge in the field of natural products. Conventional workflows using liquid chromatography (LC)-coupled high-resolution tandem mass spectrometry (MS/MS or MS²) allow the detection of relevant small molecules while providing diagnostic fragment ions for their structural assignment. Still, many natural product ex ...
liquidchromatography, etc ; equations; journals; particles; permeability; width; Show all 6 Subjects
Abstract:
... Previously introduced structural quality factor (qₘₐₓ) of LC column is a measure of its potential kinetic performance – the larger is qₘₐₓ the proportionally larger is peak capacity (nc) of isothermal and gradient analysis with the same analysis time (tₐₙₐₗ) and pressure (Δp). However, the best practically achievable column performance depends not only on qₘₐₓ, but is limited by the narrowest prac ...
high performance liquidchromatography, etc ; anisotropy; irradiation; photoisomerization; Show all 4 Subjects
Abstract:
... Asymmetric 2,7-di-tert-butyl-10b,10c-dimethyl-2′,3′-dimethyl-pyrazino[2,3-e]dihydropyrene (DMPZ-DHP) was prepared by the annulation of diamino dihydropyrene with 2,3-butanedione. Optical resolution was achieved using chiral high-performance liquid chromatography systems after the photoisomerization of DMPZ-DHP to DMPZ-metacyclophane-diene (MCPD), and its Kuhn’s anisotropy factor (g = Δε/ε) was det ...
liquidchromatography, etc ; palmitoleic acid; purification methods; separation; Show all 4 Subjects
Abstract:
... The availability of various high‐purity unsaturated fatty acids has a wide range of needs due to their different activities. The nonlinear preparative chromatography behavior and principle for purification of palmitoleic acid with octadecyl bonded stationary phases were studied. The peak broadening and the concentration distribution of the target compounds were used to compare different C18 statio ...
liquidchromatography, etc ; diodes; flavonoids; flavor; least squares; Show all 5 Subjects
Abstract:
... To accurately quantify Pericarpium Citri Reticulatae samples, trilinear structure was restored in the stacked fingerprints for more robust modeling. Initially, liquid chromatography - diode array detector - mass spectrometry (LC-DAD-MS) and head space-solid phase micro extraction coupled to gas chromatography - mass spectrometry (HS-SPME/GC-MS) were utilized to analyze Pericarpium Citri Reticulata ...
high performance liquidchromatography, etc ; pH; phytochemicals; reference standards; Show all 4 Subjects
Abstract:
... OBJECTIVES: Because the purity of the two impurities reference standard (RS) of cefathiamidine is not easy to obtain, HPLC‐PDA‐ELSD were used to determin the RRFs of cefathiamidine impurities. METHODS: Peak area correction was applied to calculate RRFs to eliminate the influence of different responses caused by the difference in pH between the two mobile phases of HPLC‐PDA and HPLC‐PDA‐ELSD. The r ...
high performance liquidchromatography, etc ; silica gel; zinc carbonate; Show all 3 Subjects
Abstract:
... Chiral mesostructured hydroxide zinc carbonate coated silica gel (CMHZC@S) was prepared by a hydrothermal route using amino acids as symmetry-breaking agents. CMHZC@S with three levels of hierarchical chiralities, as a chiral stationary phase (CSP), showed enantiomeric separation ability for high performance liquid chromatography (HPLC). ...
liquidchromatography, etc ; dimensions; journals; pesticides; polysaccharides; pumps; sampling; Show all 7 Subjects
Abstract:
... This work demonstrates the potential of two-dimensional liquid chromatography (2D-LC) to increase the resolution capacity of multiple pesticides in a single analysis of samples that contain both chiral and achiral compounds. The setup is based on the combination of a chiral column in the first dimension and an achiral column in the second dimension using the on-line full comprehensive mode (LC × L ...
high performance liquidchromatography, etc ; chitosan; drugs; enantiomers; solvents; Show all 5 Subjects
Abstract:
... In the recent years, the resolution of drug enantiomers has received widespread attention in the medical field. It is of great practical significance to develop an efficient chiral separation material for drug analysis. Based on the distinct advantages of both favorable separation performance and good solvent tolerance, chitosan bis(4-methylphenylcarbamate)-(isobutylurea) was chosen as a chiral se ...
reversed-phase liquidchromatography, etc ; countercurrent chromatography; methanol; solvents; Show all 4 Subjects
Abstract:
... In the present work, influence of solvent strength of aqueous phase for two frequently-used biphasic solvent system in partition coefficient (K) of selected solutes were mainly studied, and a new method for selection of biphasic solvent system was proposed for high-speed countercurrent chromatographic separations. Solvent strength was referred to the typical theory that was deeply investigated in ...
liquidchromatography, etc ; food composition; mass spectrometry; ochratoxin A; Show all 4 Subjects
Abstract:
... This article discussed a development, optimization, and validation of modified QuEChERS method with liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) operated in time-of-flight multiple-reaction-monitoring (TOF-MRM) mode for the analysis of ochratoxin A and aflatoxins (B₁, B₂, G₁, G₂) in cocoa beans. The recoveries for the optimized and validated method at 2 and 5 ng/g ...
liquidchromatography, etc ; colorimetry; hydrolysis; metabolism; plant biochemistry; polymers; proanthocyanidins; Show all 7 Subjects
Abstract:
... Proanthocyanidins (PAC) are an important and widely spread class of natural products with various bioactivities. The analytical evaluation of oligomeric and polymeric proanthocyanidins in complex extracts is still challenging, due to the complexity of structures. Nevertheless, in the last 20 years analytical techniques especially in the field of chromatography and mass spectrometry have been impro ...
liquidchromatography, etc ; chloramphenicol; kaempferol; mass spectrometry; quantitative analysis; separation; Show all 6 Subjects
Abstract:
... Semens of Astragali Complanati own anti‐erectile dysfunction effect; however, the components which contribute to the anti‐erectile dysfunction effect remain unclear. This work raised a strategy that integrates liquid chromatography coupled mass spectrometry‐based quantitative analysis, anti‐erectile dysfunction assessment on impotent rats, and their relationship analysis for pinpointing anti‐erect ...