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1.
Magdalena C. Waldhier Michael A. Gruber Katja Dettmer Peter J. Oefner 《Analytical and bioanalytical chemistry》2009,394(3):695-706
Free amino acids are typically quantified as the sum of their enantiomers, because in terrestrial organisms they mainly exist
in the left-handed form. However, with increasing understanding of the biological significance of right-handed amino acids
interest in enantioselective quantification of amino acids has steadily increased. Initially, electrophoretic and chromatographic
methods using chiral (pseudo)-stationary phases or chiral eluents were applied to the separation of amino acid enantiomers.
Later, derivatization of amino acids prior to chromatography with chiral reagents gained in popularity, because the diastereomers
formed can be resolved on conventional reversed-phase columns. Novel multi-interaction chiral columns turned attention back
to direct chiral chromatographic methods. Hyphenation to mass spectrometry has increasingly replaced optical detection because
of superior selectivity, although this has not obviated the need for baseline resolution of amino acid enantiomers. Despite
the progress made, enantioselective separation and quantification of amino acids remains an analytical challenge owing to
frequently incomplete resolution of all naturally occurring enantiomers and insufficient sensitivity for the determination
of the trace amounts of d-amino acids typically found in biological fluids and tissues.
Chiral GC-MS analysis of heptafluorobutanol/pentafluoropropionanhydride amino acid derivatives on an Rt-gDEXsa column 相似文献
2.
Popot MA Woolfitt AR Garcia P Tabet JC 《Analytical and bioanalytical chemistry》2008,390(7):1843-1852
The insulin-like-growth factor (IGF-I) peptide is considered to be the main indirect marker for growth hormone administration
(GH) in a horse. Further to a previous investigation on measurement of IGF-I in plasma samples by mass spectrometry, this
study focuses on quantitative and qualitative analysis of intact IGF-I in horse plasma. First, protein-transposing software
has been developed for IGF-I to facilitate its quantification by HPLC–electrospray–ion-trap mass spectrometry. Second, product-ion
scan experiments on IGF-I have been conducted on standard samples, non-fortified equine plasma samples, fortified plasma samples,
and equine GH post-administration samples. This “top-down” approach method enables characterisation of fragment ions corresponding
to the carboxy terminal end, which can be useful for the confirmation of the presence of IGF-I in plasma samples.
Figure Structure of IGF-I and amino acid sequences of IGF-I and R3 IGF-I. Deconvolution mass spectra of the IGF-I and R3 IGF-I mixture 相似文献
3.
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
4.
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
5.
The paper reviews the state-of-art for micro optical fluidic systems (MOFS), or optofluidics, which employs optics and fluidics
in a microsystem environment to perform novel functionalities and in-depth analysis in the biophysical area. Various topics,
which include the introduction of MOFS in biomedical engineering, the implementation of near-field optics and also the applications
of MOFS to biophysical studies, are discussed. Different optical detection techniques, such as evanescent wave, surface plasmon
resonance, surface enhanced Raman scattering, resonators and transistors, have been studied extensively and integrated into
MOFS. In addition, MOFS also provides a platform for various studies of cell biophysics, such as cell mass determination and
cell Young’s modulus measurement.
Figure Cell encapsulation and trapping for refractive index measurement in MOFS 相似文献
6.
The element sulfur is almost omnipresent in all natural proteomes and plays a key role in protein quantification. Incorporated
in the amino acids cysteine and methionine, it has been served as target for many protein-labeling reactions in classic quantitative
proteomic approaches based on electrospray or MALDI mass spectrometry. This critical review discusses the potential and limitations
of sulfur isotope dilution analysis (IDA) by inductively coupled plasma—mass spectrometry (ICP-MS) for absolute protein quantification.
The development of this approach was made possible due to the improved sensitivity and accuracy of sulfur isotope ratio measurement
by ICP-MS in recent years. The unique feature of ICP-MS, compound-independent ionization, enables compound (species)-unspecific
sulfur IDA. This has the main advantage that only one generic sulfur standard (i.e., one isotopically labeled sulfur spike)
is required to quantify each peptide or protein in a sample provided that they are completely separated in chromatography
or electrophoresis and that their identities are known. The principles of this approach are illustrated with selected examples
from the literature. The discussion includes also related fields of P/S and metal/S ratio measurements for the determination
of phosphorylation degrees of proteins and stoichiometries in metalloproteins, respectively. Emerging new areas and future
trends such as protein derivatization with metal tags for improved sensitivity of protein detection in ICP-MS are discussed.
Figure The key role of sulfur in protein quantification 相似文献
7.
Bo Xu Xiaojun Feng Youzhi Xu Wei Du Qingming Luo Bi-Feng Liu 《Analytical and bioanalytical chemistry》2009,394(7):1911-1917
Analysis of complex biological samples requires the use of high-throughput analytical tools. In this work, a microfluidic
two-dimensional electrophoresis system was developed with mercury-lamp-induced fluorescence detection. Mixtures of 20 standard
amino acids were used to evaluate the separation performance of the system. After fluorescent labeling with fluorescein isothiocyanate,
mixtures of amino acids were separated by micellar electrokinetic chromatography in the first dimension and by capillary zone
electrophoresis in the second. A double electrokinetic valve system was employed for the sample injection and the switching
between separation channels. Under the optimized conditions, 20 standard amino acids were effectively separated within 20 min
with high resolution and repeatability. Quantitative analysis revealed linear dynamic ranges of over three orders of magnitudes
with detection limits at micromolar range. To further evaluate the reliability of the system, quantitative analysis of a commercial
nutrition supplement liquid was successfully demonstrated.
Figure 相似文献
8.
Sergi M Bafile E Compagnone D Curini R D'Ascenzo G Romolo FS 《Analytical and bioanalytical chemistry》2009,393(2):709-718
An analytical procedure for the simultaneous determination in human plasma and oral fluids of several illicit drugs belonging
to different chemical and toxicological classes is presented. Amphetamine, methamphetamine, morphine, 6-monoacetylmorphine,
methylenedioxyamphetamine, methylenedioxyethylamphetamine, methylenedioxymethamphetamine, cocaine, benzoylecgonine, tetrahydrocannabinol,
carboxytetrahydrocannabinol, ketamine, and phencyclidine have been quantified in real samples using a very rapid sample treatment,
basically a protein precipitation. The quantitative analysis was performed by liquid chromatography–tandem mass spectrometry
and has been fully validated. All the analytes were detected in positive ionization mode using a TurboIonSpray source, except
carboxytetrahydrocannabinol, which was detected in negative ionization mode. The use of a diverter valve between the column
and the mass spectrometer allows the preservation of the ion source performances for high-throughput analysis.
Figure Diverter system 相似文献
9.
Individual transfer ribonucleic acids (tRNAs) in a complex mixture can be identified by the matrix-assisted laser desorption/ionization
mass spectrometry (MALDI-MS) detection of their signature digestion products. Signature digestion products are endonuclease
digestion products whose mass-to-charge value is unique thus corresponding to only a single tRNA. To improve the effectiveness
of this approach, we have expanded the applicable endonucleases and examined the use of multiple endonucleases for tRNA identification.
The purine specific endonucleases RNase T1 and RNase TA generate the largest number of predicted signature digestion products.
Experimentally, MALDI-MS analysis of endonuclease digests from Escherichia coli and Bacillus subtilis finds that any two endonucleases used in combination increases tRNA identification by about 25% over the number identified
with a single endonuclease. Using three endonucleases, RNase T1, RNase A, and RNase TA, further improves the number of tRNAs
identified by 10–15% over those found with two endonucleases. Limitations in the MALDI-MS approach for complex mixtures were
revealed in this study, suggesting that the direct MALDI-MS analysis of signature digestion products is more effective for
organisms having 30 or less unique tRNAs.
Figure Signature digestion products for tRNACys 相似文献
10.
Zaher M Ravelet C Baussanne I Ravel A Grosset C Décout JL Peyrin E 《Analytical and bioanalytical chemistry》2009,393(2):655-660
In this paper, we describe the preparation and the evaluation of a porous graphitic carbon (PGC) column coated with a new
dinaphthyl derivative of neamine for chiral ligand-exchange (LE) chromatography. It was shown that the graphitic surface/dinaphthyl
anchor system efficiently (1.15 μmol/m2) and stably (three months of intensive use) adsorbs the neamine template onto the chromatographic support. The resulting
coated PGC stationary phase showed appreciable LE-based enantioselective properties towards several native amino acids.
Chromatographic separation of methionine enantiomers using a dinaphtyl neamine-based ligand-exchange chiral stationary phase 相似文献
11.
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
12.
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
13.
Stir bar sorptive extraction in combination with thermal desorption coupled online to capillary gas chromatography–mass spectrometry
was applied to investigate volatile and semivolatile fractions in two waste leachate samples: old and fresh ones. The present
study helps to improve our knowledge of waste leachate organic composition. The aim is to then make use of this knowledge
afterwards in order to generate more reliable and specific treatment processes for waste leachates and thus to respect the
environmental statute law regarding their rejection. The volatile and semivolatile compounds appeared to be mainly anthropogenic
in origin. Moreover, lactic acid and cyclic octaatomic sulfur could potentially be used as microbiological activity indicators,
since they occur during organic matter degradation processes within waste leachates.
Figure TDU-CGC-MS analytical equipment 相似文献
14.
Jackson AT Slade SE Thalassinos K Scrivens JH 《Analytical and bioanalytical chemistry》2008,392(4):643-650
The end-group functionalisation of a series of poly(propylene glycol)s has been characterised by means of electrospray ionisation–tandem
mass spectrometry (ESI-MS/MS). A series of peaks with mass-to-charge ratios that are close to that of the precursor ion were
used to generate information on the end-group functionalities of the poly(propylene glycol)s. Fragment ions resulting from
losses of both of the end groups were noted from some of the samples. An example is presented of how software can be used
to significantly reduce the length of time involved in data interpretation (which is typically the most time-consuming part
of the analysis).
Figure Screenshot from Polymerator software of annotated ESI-MS/MS spectrum from the lithiated heptamer of poly(propylene glycol)
di-acrylate 相似文献
15.
Beatriz Fernández Jose Manuel Costa Rosario Pereiro Alfredo Sanz-Medel 《Analytical and bioanalytical chemistry》2010,396(1):15-29
Inorganic mass spectrometry techniques may offer great potential for the characterisation at the nanoscale, because they provide
unique elemental information of great value for a better understanding of processes occurring at nanometre-length dimensions.
Two main groups of techniques are reviewed: those allowing direct solid analysis with spatial resolution capabilities, i.e.
lateral (imaging) and/or in-depth profile, and those for the analysis of liquids containing colloids. In this context, the
present capabilities of widespread elemental mass spectrometry techniques such as laser ablation coupled with inductively
coupled plasma mass spectrometry (ICP-MS), glow discharge mass spectrometry and secondary ion/neutral mass spectrometry are
described and compared through selected examples from various scientific fields. On the other hand, approaches for the characterisation
(i.e. size, composition, presence of impurities, etc.) of colloidal solutions containing nanoparticles by the well-established
ICP-MS technique are described. In this latter case, the capabilities derived from the on-line coupling of separation techniques
such as field-flow fractionation and liquid chromatography with ICP-MS are also assessed. Finally, appealing trends using
ICP-MS for bioassays with biomolecules labelled with nanoparticles are delineated.
相似文献
16.
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
17.
Kallio M Jussila M Raimi P Hyötyläinen T 《Analytical and bioanalytical chemistry》2008,391(6):2357-2363
A previously constructed semi-rotating cryogenic modulator was modified for comprehensive two-dimensional gas chromatography
(GC×GC). The retention time repeatability was improved by replacing the modulator control program unit with a new system.
Peak widths obtained with the modified modulator were comparable with those obtained with the previous modulator and other
modulator types. The modulator was easy to construct and it can be installed in any commercial GC system. The constructed
GC×GC–FID system and data obtained by gas chromatography–mass spectrometry (GC–MS) were used for identification of unknowns
in forest aerosol samples.
Figure A semi-rotating cryogenic modulator in which modulation is based on two-step cryogenic trapping with continuously flowing
carbon dioxide has been developed for comprehensive two-dimensional gas chromatography 相似文献
18.
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
19.
Determination of antimicrobial residues and metabolites in the aquatic environment by liquid chromatography tandem mass spectrometry 总被引:2,自引:0,他引:2
Antimicrobials are used in large quantities in human and veterinary medicine. Their environmental occurrence is of particular
concern due to the potential spread and maintenance of bacterial resistance. After intake by the organisms, the unchanged
drug and its metabolized forms are excreted and enter wastewater treatment plants where they are mostly incompletely eliminated,
and are therefore eventually released into the aquatic environment. The reliable detection of several antimicrobials in different
environmental aqueous compartments is the result of great improvements achieved in analytical chemistry. This article provides
an overview of the more outstanding analytical methods based on liquid chromatography tandem mass spectrometry, developed
and applied to determine antimicrobial residues and metabolites present in surface, waste, and ground waters.
相似文献
20.
Krupp EM Milne BF Mestrot A Meharg AA Feldmann J 《Analytical and bioanalytical chemistry》2008,390(7):1753-1764
Mercury in plants or animal tissue is supposed to occur in the form of complexes formed with biologically relevant thiols
(biothiols), rather than as free cation. We describe a technique for the separation and molecular identification of mercury
and methylmercury complexes derived from their reactions with cysteine (Cys) and glutathione (GS): Hg(Cys)2, Hg(GS)2, MeHgCys, MeHgGS. Complexes were characterised by electrospray mass spectrometry (MS) equipped with an ion trap and the fragmentation
pattern of MeHgCys was explained by using MP2 and B3LYP calculations, showing the importance of mercury–amine interactions
in the gas phase. Chromatographic baseline separation was performed within 10 min with formic acid as the mobile phase on
a reversed-phase column. Detection was done by online simultaneous coupling of ES-MS and inductively coupled plasma MS. When
the mercury complexes were spiked in real samples (plant extracts), no perturbation of the separation and detection conditions
was observed, suggesting that this method is capable of detecting mercury biothiol complexes in plants.
Figure Separation and structural identification of Hg and MeHg biothiols
A part of this work was presented as a poster at the European Winter Conference on Plasma Spectrochemistry, 2007, held in
Taormina, Italy. 相似文献