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1.
4,4′-methylenedianiline (DAPM) is the main building block for production of 4,4′-methylenediphenyldiisocyanate that has been
widely used in the manufacturing of polyurethane materials including medical devices. Although it was revealed that damage
to biliary epithelial cells of the liver and common bile duct occurred upon acute exposure to DAPM, the exact mechanism of
DAPM toxicity is not fully understood. Both phase I and II biotransformations of DAPM, some of which generate reactive intermediates,
are characterized in detail by liquid chromatography electrospray tandem mass spectrometry. The two most prominent metabolites
found in rat bile (M2 and M7) implicated glutathione, glucuronic acid, and glycine conjugations (phase II) following hydroxylation,
and N-oxidation (phase I). Their decomposition pathways, as evidenced by MS
n
experiments, have been elucidated in detail.
Figure Proposed fragmentation pathways of a DAPM metabolite 相似文献
2.
Pérez Pavón JL García Pinto C Guerrero Peña A Moreno Cordero B 《Analytical and bioanalytical chemistry》2008,391(2):599-607
In the present work we report the results obtained with a methodology based on direct coupling of a headspace generator to
a mass spectrometer for the identification of different types of petroleum crudes in polluted soils. With no prior treatment,
the samples are subjected to the headspace generation process and the volatiles generated are introduced directly into the
mass spectrometer, thereby obtaining a fingerprint of volatiles in the sample analysed. The mass spectrum corresponding to
the mass/charge ratios (m/z) contains the information related to the composition of the headspace and is used as the analytical signal for the characterization
of the samples. The signals obtained for the different samples were treated by chemometric techniques to obtain the desired
information. The main advantage of the proposed methodology is that no prior chromatographic separation and no sample manipulation
are required. The method is rapid, simple and, in view of the results, highly promising for the implementation of a new approach
for oil spill identification in soils.
Figure PCA score plots illustrate clear discrimination of types of crude oil in polluted soil samples (e.g. results are shown for
vertisol) 相似文献
3.
Covalent adduction of the model protein apomyoglobin by 4-hydroxy-2-nonenal, a reactive end-product of lipid peroxidation,
was characterized by nanoelectrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (FTICR). The
high mass resolving power and mass measurement accuracy of the instrument facilitated a detailed compositional analysis of
the complex reaction product without the need for deconvolution and transformation to clearly show the pattern of adduction
and component molecular weights. Our study has also demonstrated the value of electron capture dissociation over collision-induced
dissociation for the tandem mass spectrometric determination of site modification for the 4-hydroxy-2-nonenal adduct of oxidized
insulin B chain as an example.
Figure FTICR allowed characterization of 4-hydroxy-2-nonenal (HNE)-modified apomyoglobin (an expanded spectrum of the +15 charge
state is shown) 相似文献
4.
Purification methods for proteomics samples are of crucial concern for improving the quality of the sample delivered to the
mass spectrometer. They constitute the link between the mass spectrometer and protein processing and peptide isolation steps
that usually require solvents, buffers, or detergents completely incompatible with MS-analysis conditions. This work describes
three new clean-up procedures using synthetic membranes and polymer media and compares them with standard procedures. The
efficiency of each of the purification procedures was studied via application to four standards and two membrane proteins.
This work highlights the importance of versatility in sample preparation, especially for MS-based proteomic investigations.
Figure PMF spectra obtained after MALDI-TOF measurements of bovine mitochondrial complex III (A) and complex IV (B) in-solution digests, with and without purification 相似文献
5.
Application of surface chemical analysis tools for characterization of nanoparticles 总被引:1,自引:1,他引:0
D. R. Baer D. J. Gaspar P. Nachimuthu S. D. Techane D. G. Castner 《Analytical and bioanalytical chemistry》2010,396(3):983-1002
The important role that surface chemical analysis methods can and should play in the characterization of nanoparticles is
described. The types of information that can be obtained from analysis of nanoparticles using Auger electron spectroscopy
(AES), X-ray photoelectron spectroscopy (XPS), time-of-flight secondary-ion mass spectrometry (TOF-SIMS), low-energy ion scattering
(LEIS), and scanning-probe microscopy (SPM), including scanning tunneling microscopy (STM) and atomic force microscopy (AFM),
are briefly summarized. Examples describing the characterization of engineered nanoparticles are provided. Specific analysis
considerations and issues associated with using surface-analysis methods for the characterization of nanoparticles are discussed
and summarized, with the impact that shape instability, environmentally induced changes, deliberate and accidental coating,
etc., have on nanoparticle properties.
相似文献
6.
Herschbach H Hosomizu K Hahn U Leize E Van Dorsselaer A Imahori H Nierengarten JF 《Analytical and bioanalytical chemistry》2006,386(1):46-51
The electrospray mass spectrometric characterization of neutral dendrons with a carboxylic acid function or a t-butyl ester moiety at the central point and up to eight peripheral C60 subunits has been performed and is described in detail. Molecules bearing a carboxylic acid group at the center turned out
to be preferentially ionized by deprotonation, whereas those with a t-butyl ester head group were ionized by reduction of the C60 units in the infusion capillary of the electrospray source.
Electronic supplementary material Supplementary material is available for this article at and is accessible for authorized users. 相似文献
7.
Pyochelin is a siderophore and virulence factor common to Burkholderia cepacia and several Pseudomonas strains. It is isolated from bacterial media as a mixture of two epimers, which readily equilibrate in most solvents. Experiments based on high-performance liquid chromatography/electrospray ionization mass spectrometry are reported here, allowing the investigation of the different Fe(III)-chelating properties of pyochelin diastereomers in solution without the need for labourious isolation. It is demonstrated in this study that only one of the two pyochelin diastereomers is able to chelate Fe(III); no Fe(III) complexes of the other diastereomer could be detected. The Fe(III)–pyochelin complex exhibited a 1:1 metal-to-siderophore ratio and no evidence for other stoichiometries was found.
相似文献
8.
Webb A 《Analytical and bioanalytical chemistry》2007,388(3):525-528
Figure Schematic diagram of a typical arrangement used for hyphenating chemical microseparations (e.g. capillary HPLC, CE, or CEC)
with microcoil NMR detection 相似文献
9.
Emily O’Neill Danielle Harrington John Allison 《Analytical and bioanalytical chemistry》2009,393(8):2029-2038
Monitoring of cell cultures in microbioreactors is a crucial task in cell bioassays and toxicological tests. In this work
a novel tool based on a miniaturized sensor array fabricated using low-temperature cofired ceramics (LTCC) technology is presented.
The developed device is applied to the monitoring of cell-culture media change, detection of the growth of various species,
and in toxicological studies performed with the use of cells. Noninvasive monitoring performed with the LTCC microelectrode
array can be applied for future cell-engineering purposes.
Figure Microelectrode array for monitoring of cell cultures 相似文献
10.
Nora Graf Thomas Gross Thomas Wirth Wilfried Weigel Wolfgang E. S. Unger 《Analytical and bioanalytical chemistry》2009,393(8):1907-1912
The chemical composition of the functional surfaces of substrates used for microarrays is one of the important parameters
that determine the quality of a microarray experiment. In addition to the commonly used contact angle measurements to determine
the wettability of functionalized supports, X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry
(ToF-SIMS) are more specific methods to elucidate details about the chemical surface constitution. XPS yields information
about the atomic composition of the surface, whereas from ToF-SIMS, information on the molecular species on the surface can
be concluded. Applied on printed DNA microarrays, both techniques provide impressive chemical images down to the micrometer
scale and can be utilized for label-free spot detection and characterization. Detailed information about the chemical constitution
of single spots of microarrays can be obtained by high-resolution XPS imaging.
Figure Eye-catching image for the graphical online abstract 相似文献
11.
Harir M Frommberger M Gaspar A Martens D Kettrup A El Azzouzi M Schmitt-Kopplin P 《Analytical and bioanalytical chemistry》2007,389(5):1459-1467
The photodecomposition of imazamox, a herbicide of the imidazolinone family, was investigated in pure water. The main photoproducts
from the photolysis were followed over time by liquid chromatography mass spectrometry and structures were proposed from exact
mass determinations obtained by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry. The method
comprised exact mass determination with better than 0.2 ppm mass accuracy and a corresponding structural visualization taking
care of respective isotopes with an adapted van Krevelen diagram that enabled a systematic approach to the characterisation
of the elementary composition of each photoproduct. By taking advantage of the high resolving power of FT-ICR MS to make precise
formula assignments, the derived 2D van Krevelen diagram (O/C; H/C; m/z) enabled one to structurally differentiate the formed photoproducts and to propose a degradation pathway for imazamox.
Figure Overview of applied method to analyse the photolysis process of imazamox herbicide 相似文献
12.
Amino acids are important targets for metabolic profiling. For decades, amino acid analysis has been accomplished by either
cation-exchange or reversed-phase liquid chromatography coupled to UV absorbance or fluorescence detection of pre-column or
post-column-derivatized amino acids. Recent years have seen great progress in the development of direct-infusion or hyphenated
mass spectrometry in the analysis of free amino acids in physiological fluids, because mass spectrometry not only matches
optical detection in sensitivity, but also offers superior selectivity. The advent of cryo-probes has also brought NMR spectroscopy
within the detection limits required for the analysis of free amino acids. But there is still room for further improvement,
including expansion of the analyte spectrum, reduction of sample preparation and analysis time, automation, and synthesis
of affordable isotope standards.
Figure Fully automated gas chromatography-mass spectrometry analysis of amino acids. 相似文献
13.
Abstract One-pot, three-components synthesis of 2,4,6-triarylpyridines and 5-unsubstituted-3,4-dihydropyrimidin-2(1H)-ones was performed under solvent-free conditions using molecular iodine as the catalyst in moderate to good product yields.
Graphical abstract
相似文献
14.
Sen Hou Xinxin Li Xiaoyu Li Xi-Zeng Feng Rui Wang Chen Wang Lei Yu Ming-Qiang Qiao 《Analytical and bioanalytical chemistry》2009,394(3):783-789
Surface wettability conversion with hydrophobins is important for its applications in biodevices. In this work, the application
of a type I hydrophobin HGFI in surface wettability conversion on mica, glass, and poly(dimethylsiloxane) (PDMS) was investigated.
X-ray photoelectron spectroscopy (XPS) and water-contact-angle (WCA) measurements indicated that HGFI modification could efficiently
change the surface wettability. Data also showed that self-assembled HGFI had better stability than type II hydrophobin HFBI.
Protein patterning and the following immunoassay illustrated that surface modification with HGFI should be a feasible strategy
for biosensor device fabrication.
Figure A hydrophobin HGFI has been applied into surface wettability conversion for protein immobilization
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
15.
Bai LP Cai Z Zhao ZZ Nakatani K Jiang ZH 《Analytical and bioanalytical chemistry》2008,392(4):709-716
Spectrofluorometric titration, electrospray ionization time-of-flight mass spectrometric and UV melting methods were employed
to study the binding of chelerythrine and sanguinarine to bulged DNA. The results showed that both alkaloids bind specifically
to single pyrimidine (C, T) bulge sites. The ability of sanguinarine to bind to both regular and bulged hairpins was found
to be stronger than that of chelerythrine, but the binding selectivity of chelerythrine toward single-base bulges was much
larger than that of sanguinarine.
Figure Association constants for chelerythrine and sanguinarine toward regular and single-base bulged hairpins obtained from fluorometric
analysis 相似文献
16.
Surmeian A Diplasu C Groza A Ganciu M Belenguer P Tempez A Chapon P 《Analytical and bioanalytical chemistry》2007,388(8):1625-1629
A high-current pulsed hollow cathode discharge was used to study the role of atomic and ionic metastables involved in ionization
plasma processes. We observed the enhancement of the spectral emission lines of noble gas ions in the afterglow. A study of
the processes that involve atomic and ionic metastables is of great interest since it should lead to a better understanding
of and enhanced control over the ionization mechanisms crucial to analytical glow discharge mass spectrometry (GDMS) analysis.
Figure Time profile of Ti, Ti+, and Ne+ spectral lines 相似文献
17.
Walther C Rothe J Fuss M Büchner S Koltsov S Bergmann T 《Analytical and bioanalytical chemistry》2007,388(2):409-431
Polynuclear species of zirconium in acidic aqueous solution are investigated by combining X-ray absorption spectroscopy (XAFS)
and nanoelectrospray mass spectrometry (ESI-MS). Species distributions are measured between pHC 0 and pHC 3 for [Zr] = 1.5–10 mM. While the monomer remains a minor species, with increasing pH the degree of polymerization increases
and the formation of tetramers, pentamers, octamers, and larger polymers is observed. The high resolution of the mass spectrometer
permits the unambiguous determination of polynuclear zirconium hydroxide complexes by means of their isotopic patterns. The
relative abundances of mononuclear and polynuclear species present simultaneously in solution are measured, even if one of
the species contributes only 0.1% of the Zr concentration. For the first time it has been directly observed that the hydrolysis
of polynuclear Zr species is a continuous process which leads to charge compensation through the sequential substitution of
water molecules by hydroxide ligands until doubly charged polymers dominate at conditions (H+ and Zr concentrations) close to the solubility of Zr(OH)4(am). The invasiveness of the electrospray process was minimized by using very mild declustering conditions, leaving the polynuclear
species within a solvent shell of approximately 20 water molecules.
Figure Schematic Diagram of Multiplexed Measurement of 9 Anti-Nuclear Antibodies Using the AtheNa Multilyte Assay 相似文献
18.
This paper reports on an integrated analytical approach for the noninvasive characterization of Chinese nephrite samples,
encompassing both geological reference specimens and museum objects. Natural variations induced by cationic substitutions,
as well as human-induced alterations such as heating, which both affect color, are the focus of this contribution. Totally
noninvasive methods of analysis were used, including X-ray fluorescence spectroscopy, Raman microspectroscopy, visible reflectance
spectroscopy and X-ray diffraction; moreover, the feasibility of using a portable Raman spectrometer for the in-field identification
of jades has been demonstrated. Fe/Fe+Mg (% p.f.u.) ratios of the jades have been calculated based on hydroxyl stretching
Raman bands, which will provide an important addition to similar data that are being collected at major museums in the Western
and Eastern hemispheres.
相似文献
19.
Nattikarn Kaewkhomdee Sandra Mounicou Joanna Szpunar Ryszard Lobinski Juwadee Shiowatana 《Analytical and bioanalytical chemistry》2010,396(3):1355-1364
Sequential extraction (water, Driselase, protease XIV) and extraction with simulated gastric and intestinal fluids were proposed
to characterize the binding and the bioaccessibility of chromium in two commercial food supplements obtained by incorporation
of this element into yeast. Chromium in Cr-enriched yeast was found to be hardly extractable with water, Driselase, or simulated
gastric fluid (recoveries of approximately 10–20%), but proteolysis or gastrointestinal fluid digestion released more than
half of the chromium present. Fractionation with size-exclusion chromatography with Cr-specific detection by inductively coupled
plasma mass spectrometry (ICP MS) allowed the distinction of two fractions: one below approximately 1 kDa and one 1–5 kDa;
they contained the entirety of the released Cr with proportions varying as a function of the extracting solution and the origin
of sample. When collected and investigated by reversed-phase high-performance liquid chromatography–ICP MS, the low molecular
mass fraction was found to release Cr(III), whereas the heavier one showed most of Cr bound in fairly stable hydrophobic complexes.
However, an attempt of their identification by electrospray ionization MS/MS and matrix-assisted laser desorption ionization
MS was not successful.
相似文献
20.
The derivatization of cysteine-containing peptides with benzoquinone compounds is rapid, quantitative and specific in acidic
media. The conversion of cysteines into hydrophobic benzoquinone-adducted residues in peptides is used here to alter the chromatographic
properties of cysteinyl peptides during liquid chromatography separation. The benzoquinone derivatization is shown to allow
the accurate selection of cysteine-containing peptides of bovine serum albumin tryptic digest by diagonal reversed-phase chromatography,
which consists of one primary and a series of secondary identical liquid chromatographic separations, before and after a cysteinyl-targeted
modification of the peptides by benzoquinone compounds.
Figure Diagonal chromatographic selection of cysteinyl peptides modified with benzoquinones
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献