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1.
Glutathione peroxidase (isolated from bovine erythrocytes) and its behaviour during alkylation and enzymatic digestion were
studied by various hyphenated techniques: gel electrophoresis–laser ablation (LA) inductively coupled plasma (ICP) mass spectrometry
(MS), size-exclusion liquid chromatography–ICP MS, capillary high-performance liquid chromatography (capHPLC)–ICP MS, matrix-assisted
laser desorption/ionization (MALDI) time-of-flight (TOF) MS, electrospray MS, and nanoHPLC–electrospray ionization (ESI) MS/MS.
ESI TOF MS and MALDI TOF MS allowed the determination of the molecular mass but could not confirm the presence of selenium
in the protein. The purity of the protein with respect to selenium species could be evaluated by LA ICP MS and size-exclusion
chromatography (SEC)–ICP MS under denaturating and nondenaturating conditions, respectively. SEC–ICP MS and capHPLC–ICP MS
turned out to be valuable techniques to study the enzymolysis efficiency, miscleavage and artefact formation during derivatization
and tryptic digestion. For the first time the parallel ICP MS and ESI MS/MS data are reported for the selenocysteine-containing
peptide extracted from the gel; capHPLC–ICP MS allowed the sensitive detection of the selenopeptide regardless of the matrix
and nanoHPLC–electrospray made possible its identification.
Figure Eye catching image
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
2.
Evaporative light scattering detection (ELSD) is widely recognized as a universal tool for liquid and supercritical chromatographies.
In addition, this detection technique is fully compatible with continuous-flow systems. In fact, the combination of continuous
non-chromatographic techniques and ELSD affords the design of simple, reliable systems for extracting qualitative information.
This paper reviews instrumental innovations regarding the miniaturization of evaporative light scattering detectors and their
uses in micro and capillary liquid chromatography; also, it discusses their increasingly important role in the development
of vanguard configurations for sample screening and the determination of total indices without the need for chromatographic
separation. Moreover, it compares them with other types of chromatographic detectors in terms of performance. Finally, the
potential of ELSD for solving real-life analytical problems arising from the need to meet (bio)chemical information needs
is illustrated with various selected applications.
Figure New trends in evaporative light scattering detection: recent chromatographic uses and its role in vanguard/rearguard strategies 相似文献
3.
In proteomics, nanoflow multidimensional chromatography is now the gold standard for the separation of complex mixtures of
peptides as generated by in-solution digestion of whole-cell lysates. Ideally, the different stationary phases used in multidimensional
chromatography should provide orthogonal separation characteristics. For this reason, the combination of strong cation exchange
chromatography (SCX) and reversed-phase (RP) chromatography is the most widely used combination for the separation of peptides.
Here, we review the potential of hydrophilic interaction liquid chromatography (HILIC) as a separation tool in the multidimensional
separation of peptides in proteomics applications. Recent work has revealed that HILIC may provide an excellent alternative
to SCX, possessing several advantages in the area of separation power and targeted analysis of protein post-translational
modifications.
Figure Artistic impression of the HILIC separation mechanism 相似文献
4.
Collision-induced reporter fragmentations of the currently most important covalent peptide modifications as detected by tandem
mass spectrometry are summarized. These fragmentations comprise the formation of reporter ions, which are preferentially immonium
ions, immonium ion-derived fragments or side chain fragments. In addition, the reporter neutral loss reactions for covalently
modified amino acid residues are summarized. For each individual covalent modification which can be recognized by a reporter
fragmentation, the accurate mass shift and the gross formula shift of the modified amino acid residue are given. The same
set of data is provided for the reporter fragmentations. Finally, an extensive accurate mass and gross formula list is presented
as supplementary material, describing mostly regular and modified y1 and dipeptide a and b ions, which are helpful for identification of the peptide ends of covalently modified peptides.
Figure When modified peptides are fragmented by collision-induced dissociation in a tandem mass spectrometer, the modification is
either lost as part of a charged fragment, so that a reporter ion for the modification is generated or it is lost as part of a neutral fragment, so that a modification-specific reporter neutral loss is observed in the fragment ion spectrum.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Chien-Wen Hung and Andreas Schlosser contributed equally to this work. 相似文献
5.
Various toxicological and metabolic interactions have been reported to exist between arsenic and selenium. In the present
study, synthetic seleno-arsenic compounds, potentially suitable for probing metabolic interactions between these two elements,
were prepared and tentatively characterized by using high-performance liquid chromatography (HPLC)–electrospray tandem mass
spectrometry and HPLC–inductively coupled plasma mass spectrometry. In analogy to the recently identified thio-arsenic species,
which can be prepared from their corresponding oxo-arsenic species via reaction with H2S, the seleno-arsenic compounds were also derived from oxo-arsenic compounds via reaction with H2Se.
Figure H2Se bubbled into solutions containing oxo‐arsenosugars converts them into their seleno‐arsenosugar analogues. 相似文献
6.
Ice chromatography, in which water-ice particles are employed as a chromatographic stationary phase, has proven an efficient
technique for probing the solution/ice interface. The preparation of fine ice particles has allowed us to not only obtain
higher-resolution separation but also investigate the molecular processes occurring on the ice surface in more detail. Chromatographic
investigations have revealed that two or more hydrogen bonds are simultaneously formed between a solute and the dangling bonds
on the ice surface when the solute gives measurable retention. Several compounds, including estrogens, amino acids, and acyclic
polyethers, have been successfully separated by ice chromatography with a hexane-based mobile phase. In addition, this method
effectively probes the surface melting of the ice stationary phase and the liquid phase that coexists with water ice at thermodynamic
equilibrium. The thickness of the surface liquid layer and the size of the liquid phase that grows inside an ice particle
have been evaluated. The perspectives of this method are also discussed.
相似文献
7.
We screened a series of RNA and DNA aptamers for their ability to serve in the dye displacement assays in which analytes compete
with TO dye. We conclude that, while the performance of the TO dye displacement approach is not always predictable, it is
still a simple and sensitive assay to detect binding between RNA aptamers and small molecules. In particular, we describe
efficient assays for tobramycin and theophylline, with up to 90% displacement of TO observed, and we describe the first aptameric
assay for cAMP.
Figure An RNA or DNA aptamer against a molecule (circle) binds TO dye, resulting in a fluorescent complex. Presence of free molecule in solution results in the displacement of TO
from the complex and a reduction in fluorescence
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
8.
New fast methods for the determination of pharmacokinetic behaviour of potential drug candidates are receiving increasing
interest. We present a new homogeneous method for the determination of drug binding and drug competition for human serum albumin
and α1-acid glycoprotein that is amenable to high-throughput-screening. It is based on selective fluorescent probes and the measurement
of fluorescence polarization. This leads to decreased interference with fluorescent drugs as compared with previously published
methods based on similar probes and the measurement of fluorescence intensity. The binding of highly fluorescent drugs that
still interfere with the probes can be measured by simply titrating the drugs in a two-component system with the serum protein.
The assay may also be used to discover strongly binding protein ligands that are interesting for drug-targeting strategies.
Additionally, binding data could be obtained from larger libraries of compounds for in silico predictive pharmacokinetics.
Figure Fluorescence polarization displacement titration of dansylsarcosine (3D-structure as insert) bound to human serum albumin
(HSA) by naproxene
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
9.
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
10.
Raczyńska ED Gal JF Maria PC Zientara K Szelag M 《Analytical and bioanalytical chemistry》2007,389(5):1365-1380
Fourier transform ion cyclotron resonance mass spectrometry, combined with modern ionization (fast atom bombardment , electrospray
ionization, matrix-assisted laser desorption–ionization), fragmentation (collision-induced dissociation, surface-induced dissociation,
one-photon ultraviolet photodissociation, infrared multiphoton dissociation, blackbody infrared radiative dissociation, electron-capture
dissociation), and separation (high-performance liquid chromatography, liquid chromatography, capillary electrophoresis) techniques
is now becoming one of the most attractive and frequently used instrumental platforms for gas-phase studies of biomolecules
such as amino acids, bioamines, peptides, polypeptides, proteins, nucleobases, nucleosides, nucleotides, polynucleotides,
nucleic acids, saccharides, polysaccharides, etc. Since it gives the possibilities to trap the ions from a few seconds up
to thousands of seconds, it is often applied to study ion/molecule reactions in the gas phase, particularly proton-transfer
reactions which provide important information on acid–base properties. These properties determine in part the three-dimensional
structure of biomolecules, most of their intramolecular and intermolecular interactions, and consequently their biological
activity. They also indicate the form (unionized, zwitterionic, protonated, or deprotonated) which the biomolecule may take
in a nonpolar environment.
Figure Biomolecules in the gas-phase acidity-basicity scale 相似文献
11.
Guanine-rich DNA sequences commonly form helical quadruplex structures via Hoogsteen hydrogen bonds. The aggregation behavior
of the nanoparticles, which are functionalized with four-guanine-terminated 27-base sequences at a nanoparticle-to-DNA ratio
of 1:60, is investigated. To some extent, the guanine-quadruplex structures between the gold nanoparticles (GNPs) promote
nanoparticle aggregation. However, the coordination site of the metal ion on the nanoparticle surface is partially passivated:
the stability of guanine-rich DNA-GNPs is slightly lower than that of the usual DNA-GNPs, and the metal-ion specificity of
nanoparticle assembly is substantially decreased. Thus, a mechanism for the aggregation of guanine-rich sequence-modified
GNPs is proposed. It is possible to obtain a stable guanine-rich sequence-functionalized nanoparticle solution at high ionic
strength by regulating guanine-rich DNA sequences. The controllability of guanine-rich sequence-modified nanoparticles makes
the secondary structure of DNA a potentially useful candidate for DNA analysis and disease diagnostics.
Figure Proposed mechanism for the aggregation of G-rich sequence-functionalized GNP
Electronic supplementary material The online version of this article (doi: ) contains supplementary material, which is available to authorized users. 相似文献
12.
The efficiencies of two traditional extraction methods used in Chinese medicine (the decoction method and the maceration method)
were evaluated for the extraction of antioxidants from medicinal plants. A group of medicinal plants possessing nutritious
and tonic functions were chosen as model plants. A commonly used extraction method was used as a reference method. The antioxidant
capacities and total phenolic contents of the extracts were measured by ferric-reducing antioxidant power and Trolox equivalent
antioxidant capacity assays as well as the Folin–Ciocalteu method, respectively. The results obtained indicated that the two
traditional extraction methods could effectively extract antioxidants from medicinal plants. These extraction methods can
be applied to the analysis and purification of antioxidants in plants, respectively. At home, people can use these methods
to extract antioxidants from plants for consumption. In the food industry, these methods could be utilized to prepare crude
extracts from plants containing antioxidants for use as food additives.
Figure Relation and comparison of extraction efficiencies of two traditional extraction methods with the reference method
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
13.
Two-dimensional liquid chromatography of synthetic polymers 总被引:2,自引:0,他引:2
Dušan Berek 《Analytical and bioanalytical chemistry》2010,396(1):421-441
Two-dimensional liquid chromatography, 2D-LC of synthetic polymers is critically assessed. Similarities and differences of
2D-LC of low-molecular-mass and polymeric substances are reviewed. The rationale of application of 2D-LC to macromolecular
substances is discussed. Basic information on retention mechanisms in liquid chromatography of synthetic polymers is furnished.
The principles, reasons, and significance of coupling of retention mechanisms are explained. The resulting separation processes
are elucidated, and the technical concepts of the corresponding experimental arrangements are described. The benefits of 2D-LC
are demonstrated together with numerous problems and shortcomings of the method.
相似文献
14.
Natalini B Sardella R Camaioni E Gioiello A Pellicciari R 《Analytical and bioanalytical chemistry》2007,388(8):1681-1688
The discovery that bile acids are involved in the modulation of nuclear steroid receptors has prompted renewed interest in
this field of research. Due to the nature of research in this field, a technique that enables simple and effective assessment
of the hydrophobic/hydrophilic balance, thus improving and speeding up evaluations of the biological profiles of these compounds,
is greatly needed. In this context, both CMC value determination and RP-HPLC mobility evaluation were explored as possible
approaches. While the CMC was calculated using the noninvasive conductimetric method, the RP-HPLC mobility was assessed by
measuring the retention factor at several mobile phase compositions and extrapolating back to the pure aqueous mobile phase.
The correlation of the CMC with the derived chromatographic hydrophobic index ϕ
0 was satisfactory.
Figure Experimental versus predicted pCMC values 相似文献
15.
Lee WC Cheng CH Pan HH Chung TH Hwang CC 《Analytical and bioanalytical chemistry》2008,390(4):1101-1109
Recent efforts in the investigation of chromatographic characterization of molecularly imprinted polymers (MIPs) have focused
mainly on the nature of heterogeneous binding sites. More data on the thermodynamics than on the kinetic features of MIP columns
have been published. The present article addresses the sources of peak broadening and tailing, which are the main drawbacks
often associated with imprinted polymers in chromatography for practical applications. With use of the theory of nonlinear
chromatography, the peak properties of a MIP column, including the retention and peak broadening and tailing, can be well
interpreted. Efforts to improve chromatographic efficiency using MIPs prepared by approaches different from the conventional
method, including covalent imprinting and the format of uniformly sized spherical microbeads, are reviewed and discussed.
This review leads to the conclusion that nonlinear chromatography theory is useful for characterizing chromatographic features
of MIP columns, since a MIP is essentially an affinity-based chromatographic stationary phase. We expect more theoretical
and experimental studies on the kinetic aspects of MIP columns, especially the factors influencing the apparent rate constant,
as well as the analysis of the influences of mobile-phase composition on the chromatographic performance. In addition to revealing
the affinity interaction by molecular recognition, slow nonspecific interactions which may be inherited from the imperfect
imprinting and may be involved in the rebinding of the template to MIPs also need to be characterized.
Figure The peak broadening and tailing associated often with molecularly imprinted polymers (MIPs) in column chromatography for practical
applications can be well characterized by the theory of nonlinear chromatography. 相似文献
16.
Tuulia Hyötyläinen 《Analytical and bioanalytical chemistry》2009,394(3):743-758
Sample preparation before chromatographic separation is the most time-consuming and error-prone part of the analytical procedure.
Therefore, selecting and optimizing an appropriate sample preparation scheme is a key factor in the final success of the analysis,
and the judicious choice of an appropriate procedure greatly influences the reliability and accuracy of a given analysis.
The main objective of this review is to critically evaluate the applicability, disadvantages, and advantages of various sample
preparation techniques. Particular emphasis is placed on extraction techniques suitable for both liquid and solid samples.
Figure Miniaturised extraction techniques allow sensitive analysis of also small sample volumes. 相似文献
17.
Subash C. B. Gopinath Koichi Awazu Makoto Fujimaki Katsuaki Sugimoto Yoshimichi Ohki Tetsuro Komatsubara Junji Tominaga Penmetcha K. R. Kumar 《Analytical and bioanalytical chemistry》2009,394(2):481-488
Biological self-assembly is a natural process that involves various biomolecules, and finding the missing partner in these
interactions is crucial for a specific biological function. Previously, we showed that evanescent-field-coupled waveguide-mode
sensor in conjunction with a SiO2 waveguide, the surfaces which contain cylindrical nanometric holes produced by atomic bombardment, allowed us to detect efficiently
the biomolecular interactions. In the present studies, we showed that the assembly of biomolecules can be monitored using
the evanescent-field-coupled waveguide-mode biosensor and thus provide a methodology in monitoring assembly process in macromolecular
machines while they are assembling.
Evanescent-field-coupled waveguide-mode sensor
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
18.
Rosenberg E 《Analytical and bioanalytical chemistry》2008,391(1):33-57
This review discusses the characterisation of natural organic dyestuffs of historical interest by liquid chromatography–mass
spectrometry. The structures of the most important natural organic dyestuffs traditionally used are presented and discussed
from the perspective of their analytical chemical determination. The practical aspects of the determination of this inhomogeneous
range of compounds with different structures, such as anthraquinones, flavonoids, indigoids or tannins, are discussed with
their implications for sample preparation, liquid chromatographic separation and mass spectrometric detection. The particular
focus of this review is the discussion of the mass spectral fragmentation patterns of the different classes of natural organic
dyestuffs, which in the ideal case allow the identification of the dyestuff actually used, and thereby provide a key to the
better characterisation and understanding of historical objects dyed with natural organic dyestuffs.
Figure LC-MS allows characterisation of natural dyestuff constituents: the MS spectrum of alizarin is superimposed over a photo of
a textile coloured using this red dye 相似文献
19.
Templating is an effective way for the structural modifications of a material and hence for altering its functional properties.
Here protein imprinting was exploited to alter polymeric polyacrylamide (PAA) membranes. The sieving properties and selection
abilities of the material formed were evaluated by studying the electrically driven transport of various proteins across templated
PAA membranes. The sieving properties correlated with the templating process and depended on the quantity of template used
during the polymerisation. For 1 mg/mL protein-templated membranes a ‘gate effect’ was shown, which induced a preferential
migration of the template and of similar-size proteins. Such template preferential electrotransport was exploited for the
selective removal of certain proteins in biological fluids prior to proteome analysis (depletion of albumin from human serum);
the efficiency of the removal was demonstrated by analysing the serum proteome by two-dimensional electrophoresis experiments.
Figure PAA templeted membrane for the electroremoval of serum albumin before proteome analysis 相似文献
20.
Telomerase is a potentially important biomarker and a prognostic indicator of cancer. Several techniques for assessing telomerase
activity, including the telomeric repeat amplification protocol (TRAP) and its modified versions, have been developed. Of
these methods, real-time quantitative TRAP (RTQ-TRAP) is considered the most promising. In this work, a novel RTQ-TRAP method
is developed in which a telomeric repeats-specific molecular beacon is used. The use of the molecular beacon can improve the
specificity of the RTQ-TRAP assay, making the method suitable for studying the overall processivity results and the turnover
rate of telomerase. In addition, the real-time, closed-tube protocol used obviates the need for post-amplification procedures,
reduces the risk of carryover contamination, and supports high throughput. Its performance in synthetic telomerase products
and cell extracts suggests that the developed molecular beacon assay can further enhance the clinical utility of telomerase
activity as a biomarker/indicator in cancer diagnosis and prognosis. The method also provides a novel approach to the specific
detection of some particular gene sequences to which sequence-specific fluorogenic probes cannot be applied directly.
Figure Real-time PCR detection of telomerase activity using specific molecular beacon probes
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献