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111.
Tolonen A Petsalo A Turpeinen M Uusitalo J Pelkonen O 《Journal of mass spectrometry : JMS》2007,42(7):960-966
A sensitive and rugged LC/MSMS method was developed for a comprehensive in vitro metabolic interaction screening assay with N-in-1 approach reported earlier. A cocktail consisting of ten cytochrome P450 (CYP)-selective probe substrates with known kinetic, metabolic and interaction properties in vivo was incubated in a pool of human liver microsomes, and metabolites of melatonin (CYP1A2), coumarin (CYP2A6), bupropion (CYP2B6), amodiaquine (CYP2C8) tolbutamide (CYP2C9), omeprazole (CYP2C19 and CYP3A4), dextromethorphan (CYP2D6), chlorzoxazone (CYP2E1), midazolam (CYP3A4) and testosterone (CYP3A4) were simultaneously analysed with a single LC/MSMS run. Altogether, 13 metabolites and internal standard phenacetin were analysed in multiple reaction mode. Polarity switching mode was utilized to acquire negative ion mode electrospray data for hydroxychlorzoxazone and positive ionization data for the rest of the analytes. Fast gradient elution was applied, giving total injection cycle of 8 min. The method was modified for two different LC/MSMS systems, and was validated for linear range, detection limit, accuracy and precision for each metabolite. In addition, cocktail inhibition system was further tested using monoclonal anti-CYP antibodies as inhibitors for each probe reaction. 相似文献
112.
Identification of bupropion urinary metabolites by liquid chromatography/mass spectrometry 总被引:1,自引:0,他引:1
Petsalo A Turpeinen M Tolonen A 《Rapid communications in mass spectrometry : RCM》2007,21(16):2547-2554
Human urinary metabolism of the antidepressant bupropion was studied using liquid chromatography/time-of-flight mass spectrometry (LC/TOFMS) and liquid chromatography/tandem mass spectrometry (LC/MS/MS). A total of 20 metabolites were detected and identified. The phase I metabolism included formation of morpholinohydroxybupropion, threo- and erythrohydrobupropion, aromatic hydroxylation, butyl group hydroxylation with ketone hydrogenation and dihydroxylation. These metabolites were detected either as the free form or as glucuronide and/or sulphate conjugates. In addition also m-chlorohippuric acid was detected. Of the phase I metabolites, a dihydroxylation to the aromatic ring and to the methyl group in the middle of the substrate molecule was reported here for the first time, as well as eight of the glucuronide conjugates (to hydroxy, dihydroxy, hydroxy and hydrogenation metabolites) and three of the sulphate conjugates (to aromatic hydroxy and hydroxy and hydrogenation metabolites). 相似文献
113.
Zhen-Yu Yin Ching S. Chang Minna Karstunen Pierre-Yves Hicher 《International Journal of Solids and Structures》2010,47(5):665-677
Experimental evidences have shown deficiencies of the existing overstress and creep models for viscous behaviour of natural soft clay. The purpose of this paper is to develop a modelling method for viscous behaviour of soft clays without these deficiencies. A new anisotropic elastic–viscoplastic model is extended from overstress theory of Perzyna. A scaling function based on the experimental results of constant strain-rate oedometer tests is adopted, which allows viscoplastic strain-rate occurring whether the stress state is inside or outside of the yielding surface. The inherent and induced anisotropy is modelled using the formulations of yield surface with kinematic hardening and rotation (S-CLAY1). The parameter determination is straightforward and no additional experimental test is needed, compared to the Modified Cam Clay model. Parameters determined from two types of tests (i.e., the constant strain-rate oedometer test and the 24 h standard oedometer test) are examined. Experimental verifications are carried out using the constant strain-rate and creep tests on St. Herblain clay. All comparisons between predicted and measured results demonstrate that the proposed model can successfully reproduce the anisotropic and viscous behaviours of natural soft clays under different loading conditions. 相似文献
114.
115.
(TH)(3)PW(12) (TH=thionine, PW(12)=PW(12)O(40)(3-)) composite was prepared by direct precipitation of TH and PW(12). The (TH)(3)PW(12) was characterized via UV-vis spectrum, FT-IR, SEM, and BET surface area. PW(12) was intact during the precipitation process. The composite has a bar-like shape and relatively large surface area (Langmuir surface of (TH)(3)PW(12) was 31.59 m(2)g(-1), BET surface was 20.26 m(2)g(-1)). Using the material as the photocatalyst, rhodamine B (RhB) was efficiently bleached and mineralized under visible light irradiation (λ>420 nm). The kinetics of the photodecomposition follow the first-order reaction. The (TH)(3)PW(12) catalyst can be easily separated from the reaction system and has good stability for reuse. 相似文献
116.
Aiming at investigating the effect of structure on electrocatalytic properties, Pd(50)Ru(50) nanoparticles (NPs) with three different structures were carefully designed in a one-pot polyol process for application in formic acid electrooxidation. The three structures are: (1) single-phase PdRu nanodendrites (denoted as PR-1), (2) a mixed-phase mixture of PdRu nanodendrites and monometallic Ru NPs (denoted as PR-2), and (3) a mixed-phase mixture of monometallic Pd and Ru NPs (denoted as PR-3). From PR-1 to PR-3, the structure was varied from single-phase to mixed-phase. The relative position of Ru was altered from completely Pd-connected (PR-1), to a mixture of Pd-connected and monometallic (PR-2), and completely monometallic (PR-3). All PdRu NPs outperform the commercial Pd/C. PR-2 exhibits the highest peak current density, but its stability is slightly lower than that of PR-3. When both the current density and the durability are taken into consideration, PR-2 is the best choice of catalyst for formic acid oxidation. It indicates that both the Pd-connected Ru NPs and monometallic Ru NPs in the mixed-phase PR-2 are essential to improve the electrocatalytic properties. Our study also illustrates that the electrochemical active surface area (ECSA) and hydrogen storage capacity of the as-prepared PdRu NPs are greatly enhanced after several hundred scans in formic acid, indicating the possibility for highly restorable catalysts in direct formic acid fuel cells. 相似文献
117.
Mass transfer from the first-dimension to the second-dimension column in comprehensive two-dimensional gas chromatography (GC x GC) is normally quantitative, which means that the peak areas produced by GC x GC are equal to those obtained in one-dimensional gas chromatography (GC). In view of this relationship, it was investigated whether normal GC calibration could be used to quantify compounds analysed by GC x GC. Quantification of polycyclic aromatic hydrocarbons (PAHs) in sediment was used as a test case. It was concluded that more laborious and time-consuming GC x GC area calibration can be replaced by GC area calibration if separation quality and quantity prerequisites are met. 相似文献
118.
Mercedes Vázquez Johan Bobacka Minna Luostarinen Kari Rissanen Andrzej Lewenstam Ari Ivaska 《Journal of Solid State Electrochemistry》2005,9(5):312-319
Potentiometric ion sensors have been prepared by galvanostatic electrosynthesis of the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) doped with p-sulfonated calix[4]arene (C[4]S) and p-methylsulfonated calix[4]resorcarenes (Rn[4]S) with alkyl substituents of different chain length (R1=CH3; R2=C2H5; R3=C6H13). The bowl-shape of these doping ions makes them suitable as ionic recognition sites, and their bulky character is expected to prevent them from leaching out of the conducting polymer membrane. For comparison, sensors based on PEDOT doped with poly(styrene sulfonate) (PSS) and poly(vinyl sulfonate) (PVS) were also constructed. The resulting GC/PEDOT electrodes were conditioned in 0.01 mol L–1 AgNO3 and their performance as Ag+ ion-selective electrodes (ISEs) studied. Results reveal that selectivity and lifetime of the electrodes is affected by the doping anion structure, although all electrodes show selectivity towards Ag+ ions. Interaction of Ag+ with sulfur atoms present in the conducting polymer backbone is considered to be the main reason for this behavior. A second set of electrodes was constructed and conditioned in 0.1 mol L–1 KCl. These electrodes were tested in chloride solutions of quaternary ammonium cations, showing that C[4]S and R2[4]S exhibit significant sensitivity towards pyridinium.Dedicated to Professor György Horányi on the occasion of his 70th birthday in recognition of his outstanding contributions to electrochemistry 相似文献
119.
Minna Kallio Maarit KivilompoloSami Varjo Matti JussilaTuulia Hyötyläinen 《Journal of chromatography. A》2009,1216(14):2923-2927
User-friendly and easy-to-use laboratory-written programs for visualisation and interpretation of comprehensive two-dimensional chromatographic data were developed. The programs that are not tied to any particular commercial instrument, and data obtained either by comprehensive two-dimensional liquid (LC × LC) or gas (GC × GC) chromatography can be analysed. Operations of the programs allow visualisation of 2D and 3D plots, comparison of two 2D plots at a time, as well as determination of retention times and peak heights and volumes. 相似文献
120.