Rapid detection and structural characterization of verapamil metabolites in rats by UPLC-MSE and UNIFI platform.

High-resolution mass spectrometry (HRMS) is an important technology for studying biotransformations of drugs in biological systems. In order to process complex HRMS data, bioinformatics, including data-mining techniques for identifying drug metabolites from liquid chromatography/high-resolution mass spectrometry (LC/HRMS) or multistage mass spectrometry (MSn ) datasets as well as elucidating the detected metabolites’ structure by spectral interpretation software, are important tools. Data-mining technologies have widely been used in drug metabolite identification, including mass defect filters, product ion filters, neutral-loss filters, control sample comparisons and extracted ion chromatographic analysis. However, the metabolites identified by current different technologies are not the same, indicating the importance of technique integration for efficient and complete identification of metabolic products. In this study, a universal, high-throughput workflow for identifying and verifying metabolites by applying the drug metabolite identification software UNIFI is reported, to study the biotransformation of verapamil in rats. A total of 71 verapamil metabolites were found in rat plasma, urine and faeces, including two metabolites that have not been reported in the literature. Phase I metabolites of verapamil were identified as N-demethylation, O-demethylation, N-dealkylation and oxidation and dehydrogenation metabolites; phase II metabolites were mainly glucuronidation and sulfate conjugates, indicating that UNIFI software could be effective and valuable in identifying drug metabolites

Low temperature oxidative coupling of methane over a La(2)O(3)catalyst

The oxidative coupling of Methane could take place at 723 K over the La2O3 catalyst prepared by the precipitation method, which was about 100 K lower than the startup temperature over the commercial La2O3 catalyst. Under the conditions of 723 K, CH4/O-2 molar ratio of 3, and GHSV = 7 500 ml/(g . h), the conversion of methane and selectivity for C-2 hydrocarbons reached 26.6% and 40.8%, respectively. The characterization results showed that there was only hexagonal La2O3 over the two catalyst samples, but the catalyst prepared by precipitation had a larger specific surface area and a distinct desorption peak of adsorbed O-2 at 598 K

In situ infrared Spectroscopy of active oxygen species for oxidative coupling of methane over BaF2/La2O3 catalyst

In situ IR spectroscopy was used to study the superoxide species (O-2(-)) for oxidative coupling of methane (OCM) over the BaF2,/La2O3 catalyst. After the pretreatment of the catalyst with O-2, the IR peak at 1108-1118 cm(-1) appeared, which was assigned to O-O bond stretching vibration in O-2(-) species. After the introduction Of 1802 isotope, the IR peak at 1.108-1118 cm-1 was weakened, and the absorption peaks appeared at 1086 and 1051 cm(-1), which was consistent with the assignment of the O-18O bond and O-18 O-18 bond stretching vibrations in the superoxide species, respectively. At 700 degrees C, the superoxide species could react with CH4, accompanied by the formation of gas phase C2H4. A good correlation between the rate of O-2 consumption and the rate of C2H4 formation was observed, so the superoxide species was believed to be responsible for the OCM reaction over the BaF2/La2O3 catalyst

Polyoxometalate-supported Pd nanoparticles as efficient catalysts for the direct synthesis of hydrogen peroxide in the absence of acid or halide promoters

A Keggin-type polyoxometalate (Cs1.5H1.5PW12O40)-supported Pd catalyst is efficient for the direct synthesis of H2O2 from H-2 and O-2 in the absence of any acid or halide additives under atmospheric pressure.NSFC [20625310, 20773099, 20873110]; National Basic Research Program of China [2005CB221408]; Program for New Century Excellent Talents in Fujian Provinc

Effects of O-2 pressure on the oxidation of VOx/Pt(111)

National Basic Research Program of China (973 program) [2010CB732303, 2013CB933102]; Chinese Ministry of Education [309019]; National Natural Science Foundation of China [21033006, 21073149, 20923004, 21273178]; Program for Changjiang Scholars and Innovative Research Team in Universities [IRT1036]; PhD Programs Foundation of the Chinese Ministry of Education [20110121110010]Vanadium oxide (VOx) has been extensively used in many oxidation and selective oxidation reactions. In this study, VOx thin films were prepared in an ultra-high vacuum (UHV) chamber by evaporating V onto a Pt(111) surface followed by subsequent oxidation at 623 K in 1 x 10(-7) Torr O-2, and further oxidized in the 'high-pressure' reaction cell with 1 Torr O-2. The film quality and structure were investigated by high-resolution electron energy loss spectroscopy (HREELS), X-ray photoelectron spectroscopy (XPS), low energy electron diffraction (LEED), low energy ion scattering spectroscopy (LEIS), Auger electron spectroscopy (AES), and in situ infrared reflection absorption spectroscopy (IRAS). On the Pt(111) surface, VOx forms isolated O=VOx (x = 0-3) species, surface two-dimensional (2D) (2 x 2)-V2O3 domains, a bi-layer structure with a (3 root 3 x 6) arrangement, and a complicated tri-layer structure as the coverage increases from submonolayer to multilayer. Under the UHV conditions, the oxidation state of V is mainly +3 and the stability was found to be surface V2O3 > bi-layer V2O3 > tri-layer one. After exposing to 0.3-1 Torr O-2, VOx can be oxidized to higher oxidation states, mainly V2O5, as evidenced by the shifts of the core-level binding energies and presence of V=O. These results indicate that thorough oxidation of VOx requires sufficiently high O-2 pressure, and that vanadium-based catalysts may possess higher oxidation states under most reaction conditions in the presence of O-2

Assembling forms of active phases confined within SBA-15 channels

The assembling forms of active phases in Pd/SBA-15(ad) and MoO3/SBA-15 catalyst samples, prepared via adsorption-reduction and impregnation-reduction, respectively, were characterized by N-2 physisorption measurement. Based on N-2 adsorption-desorption isotherms, it was speculated that the palladium,species in Pd/SBA-15(ad) exist as nanoparticles, whereas the MoO3 species in MoO3/SBA-15 are layered dispersed on the wall within the SBA-15 channels. These speculations were further confirmed by HR-TEM observation. The SBA-15 confined uniform Pd nanoparticles were efficient for solvent-free aerobic oxidation of benzyl alcohol

A novel visible-light-response plasmonic photocatalyst CNT/Ag/AgBr and its photocatalytic properties

National Nature Science Foundation of China [21007021, 21076099, 21177050, 21206060]; Natural Science Foundation of Jiangsu Province [BK2012717]; Postdoctoral Foundation of China [2012M521014]; Society Development Fund of Zhenjiang [SH2011011, SH2012020]; Doctoral Innovation Fund of Jiangsu [CXLX12-0666]A facile, one-step synthesis of carbon nanotube (CNT)-loaded Ag/AgBr is reported. The as-prepared samples were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), UV/Vis absorption spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, photoluminescence (PL) spectroscopy and electrochemical impedance spectroscopy (EIS). The CNT/Ag/AgBr composite exhibited much higher photocatalytic activity than pure Ag/AgBr in degrading methyl orange (MO) dye solution. The loading amount of CNT had a significant influence on the photoactivity of the CNT/Ag/AgBr composite. When the CNT loading amount was 1.4 at%, the hybrid material showed the highest photocatalytic ability. The result showed that a small amount of CNT was beneficial for photo-generated electron transfer, which could enhance the photoactivity of CNT/Ag/AgBr. The degradation dye solution was tested by liquid chromatography/mass spectrometry (LC/MS) and total organic carbon (TOC) analysis. Based on the results, the structure of the synthesized CNT/Ag/AgBr hybrid material was verified and the possible degradation path of the MO dye was proposed. A possible visible-light photocatalytic degradation mechanism was also discussed

NiO-polyoxometalate nanocomposites as efficient catalysts for the oxidative dehydrogenation of propane and isobutane

Novel nanocomposites of NiO and polyoxometalate (Cs2.5H0.5PMo12O40) with particle sizes in the range of 5-10 nm showed exceptional oxygen and ammonia adsorption capabilities, and the nanocomposites catalyzed the oxidative dehydrogenation of propane and isobutane efficiently under mild conditions.NSFC [20625310, 20773099, 20873110]; National Basic Research Program of China [2005CB221408]; Program for New Century Excellent Talents in Fujian Provinc

Synergistic Effects of VOx−Pt Probed by the Oxidation of Propane on VOx/Pt(111)

电子邮件地址:[email protected]; [email protected]/Pt(111), which was grown layer-by-layer and exhibited a well-defined structure, was used as a model catalytic surface to study the intrinsic catalytic activity of Pt, as well as the effect of VOx additive, for the oxidation of propane. A special sample system was designed to ensure a reliable analysis of the trace amount of model catalytic reaction products. The results show that the catalytic activities for the oxidation of C3H8 on the Pt(ill) surface as adding VOx are suppressed apparently at temperatures below 400 K, but enhanced significantly at temperatures above 400 K. Maximum reaction rates are achieved at a VOx coverage of about 0.3 ML at the test temperatures of 423 and 473 K. The infrared reflection-absorption spectroscopy (IRAS) results show that the redox property of the VOx-Pt is much better than that of the bulklike VOx. This is confirmed by CO poisoning tests, in that the oxidation of VOx/Pt(111) is significantly suppressed by the coadsorbed CO. The kinetic data demonstrate that there are at least two catalytically active sites, metallic Pt and VOx-Pt interface, for the activation and oxidation of C3H8. The promotion effects of VOx on Pt for the oxidation of C3H8 can be attributed to the synergy between VOx and Pt.National Basic Research Program of China (973 program) 2010CB732303 2013CB933102 Major Project of the Chinese Ministry of Education 309019 National Natural Science Foundation of China 20923004 21033006 21073149 21273178 Program for Changjiang Scholars and Innovative Research Team in University IRT1036 Ph.D. Programs Foundation of the Chinese Ministry of Education 2011012111001

Reconstruction of surface structure of MoBiTeO/SiO2 catalyst during propane selective oxidation

The catalytic performance of MoBiTeO/SiO2 for selective oxidation of propane to acrolein was investigated, and the catalyst was characterized by means of X-ray powder diffraction, in-situ laser Raman spectroscopy, in-situ laser Raman spectroscopy, and X-ray photoelectron spectroscopy. The results showed that Te-polymolybdate species were the main active phase on the fresh catalyst. Under the conditions of 570 degrees C and C3H8/O-2/N-2 = 1.2/1/4, some Te species in the catalyst were reduced to metal Te which was volatilized during the reaction, and therefore the active surface phase of the catalyst was reconstructed, leading to the formation of MoO3 species. Along with the active surface reconstruction, both the conversion of propane and the selectivity for acrolein were increased, which was attributed to the synergistic effect between Te-polymolybdate and MoO3