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1.
Acetone plays an important role in the chemistry of both the atmosphere and the ocean, due to its potential effect on the
tropospheric HOx (= HO + HO2) budget, as well as its environmental and health effects. We discuss the development of a mobile, sensitive, selective, economical
and facile method for the determination of acetone in seawater. The method consists of derivatizing acetone to its pentafluorobenzyl
oxime using 1,2,3,4,5-pentafluorobenzylhydroxylamine (PFBHA), followed by solid-phase microextraction (SPME) and analysis
by gas chromatography/mass spectrometry (GC/MS). A detection limit of 3.0 nM was achieved. The buffering capacity of seawater
imposes challenges in using the method’s optimum pH (3.7) on seawater samples, requiring calibration standards to be made
in buffered salt water and the acidification of seawater samples and standards prior to extraction. We employed the technique
for analysis of selected surface seawater samples taken on the Nordic seas during the ARK-XX/1 cruise (R.V. Polarstern). An upper limit of 5.5–9.6 nM was observed for acetone in these waters, the first acetone measurements reported for far
North Atlantic and Arctic waters.
Simplified schematic of transformations of organic compounds at the atmosphere–ocean interface 相似文献
2.
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
3.
Céspedes R Lacorte S Ginebreda A Barceló D 《Analytical and bioanalytical chemistry》2006,385(6):992-1000
This study presents a quantitative estimation of the analysis and fate of several emerging pollutants, some of them endocrine-disrupting
compounds, in surface water samples collected at several locations along the Ter River and two of its tributaries. Influent
and effluent waters and particulate matter from five sewage treatment plants (STP) that discharge into these rivers were also
studied. The target compounds analyzed were: nonylphenol ethoxylates (NPEO), nonylphenol (NP), octylphenol (OP), bisphenol
A (BPA), phthalates, alcohol ethoxylates (AEO) and benzothiazoles. Chemical analysis by liquid chromatography–mass spectrometry
using an electrospray interface (LC–ESI–MS) revealed the presence of low amounts (between 0.06 and 17.5 μg L−1) of the target compounds NPE1+2O and NP, which were detected in 100% and 84% of the samples respectively. Maximum concentrations occurred in the STPs associated
with the municipalities of Vic and Girona. From the fate and behavior data obtained for the various compounds analyzed in
the STP influent and effluent, we can conclude that the STPs are effective at removing large amounts (more than 70%) of the
compounds studied from the water.
相似文献
4.
Martínez Ocaña R Mena Granero A Egea Gonzalez FJ Garrido Frenich A Martínez Vidal JL Plaza Bolaños P 《Analytical and bioanalytical chemistry》2008,390(5):1413-1423
A multiresidue method for determining 22 polychlorinated biphenyls (PCBs) in air has been developed and validated by gas chromatography
(GC) coupled to tandem mass spectrometry (MS/MS) using a triple quadrupole analyzer (QqQ). The method was validated in terms
of both steps of sampling and analysis. The sampling method, which is based on active sampling using polyurethane foam (PUF)
as adsorbent, was validated by generating standard atmospheres. The retention capacity of this sampling sorbent allows up
to 5 m3 of air to be sampled without any breakthrough for most compounds. Two solvent extraction methods were compared: sonication
and Soxhlet extraction with a mixture of n-hexane:diethyl ether (95:5 v/v). Both extraction methods yielded similar results, but the first one required less solvent
and time. The method exhibited good accuracy (80.3–99.8%), precision (2.2–15.2%) and lower limits that allowed quantification
and confirmation at levels as low as 0.008 ng/m3. Finally, the method was applied to the analysis of PCBs in the air in areas near to a municipal solid-waste landfill and
directly above the refuse in the landfill, where it indicatedd the presence of some of the target compounds.
Figure General chemical structure of polychlorinated biphenyls 相似文献
5.
Updated estimates of the selenomethionine content of four NIST wheat reference materials have been obtained by use of a revised
gas chromatography–stable-isotope dilution mass spectrometric method. The revised method makes use of digestion with methanesulfonic
acid, which enables more complete recovery of endogenous selenomethionine than was previously achieved by overnight denaturing
treatment in 0.1 mol L−1 HCl. The NIST wheat reference materials each contain approximately 55% of their total Se content as selenomethionine. Information
about forms of Se in reference materials adds value to these materials in Se speciation studies. Estimates of selenomethionine
content are also provided for other wheat samples, including several grown under conditions of exposure to high Se levels.
These samples also contain approximately 55% of their total Se content as selenomethionine. The consistent level of 55% of
total selenium occurring in the form of selenomethionine when the total selenium content varies by a factor of 500 is suggestive
of an active mechanism of incorporation of selenium into wheat grain.
Figure Selenomethionine content of wheat samples 相似文献
6.
Barr DB Leng G Berger-Preiss E Hoppe HW Weerasekera G Gries W Gerling S Perez J Smith K Needham LL Angerer J 《Analytical and bioanalytical chemistry》2007,389(3):811-818
The objective of our study was to compare three vastly different analytical methods for measuring urinary metabolites of pyrethroid
and pyrethrum insecticides to determine whether they could produce comparable data and to determine if similar analytical
characteristics of the methods could be obtained by a secondary laboratory. This study was conducted as a part of a series
of validation studies undertaken by the German Research Foundation’s Committee on the Standardization of Analytical Methods
for Occupational and Environmental Medicine. We compared methods using different sample preparation methods (liquid–liquid
extraction and solid-phase extraction with and without chemical derivatization) and different analytical detection methods
(gas chromatography–mass spectrometry (single quadrupole), gas chromatography–high resolution mass spectrometry (magnetic
sector) in both electron impact ionization and negative chemical ionization modes, and high-performance liquid chromatography–tandem
mass spectrometry (triple quadrupole) with electrospray ionization). Our cross validation proved that similar analytical characteristics
could be obtained with any combination of sample preparation/analytical detection method and that all methods produced comparable
analytical results on unknown urine samples.
Cross-method comparison using unknown urine samples revealed reasonably good agreement for any combination of the methods
tested 相似文献
7.
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
8.
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
9.
n-Butyl benzyl phthalate (BBP) is an endocrine-disrupting chemical. A bacterium species capable of using BBP as the sole source
of carbon and energy was isolated from mangrove sediment. Effects of BBP concentration, pH, temperature, and salinity on BBP
biodegradation were studied. The optimum pH, temperature, and salinity for the BBP biodegradation were 7.0, 37°C, and 15 g L−1, respectively. BBP was completely degraded within 6 days under optimum conditions, and the biodegradation of BBP could be
fitted to a first-order kinetic model. The major metabolites of BBP biodegradation were identified as mono-butyl phthalate,
mono-benzyl phthalate, phthalic acid, and benzoic acid by using high-performance liquid chromatography and gas chromatography–mass
spectrometry. A preliminary metabolic pathway was proposed for the biodegradation of BBP.
相似文献
10.
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
11.
Han X Wang C He L Beesley TE Armstrong DW 《Analytical and bioanalytical chemistry》2007,387(8):2681-2697
A new synthetic polymeric chiral stationary phase for liquid chromatography was prepared via free-radical-initiated polymerization
of trans-9,10-dihydro-9,10-ethanoanthracene-(11S,12S)-11,12-dicarboxylic acid bis-4-vinylphenylamide. The new polymeric chiral stationary phase (CSP) showed enantioselectivity
for many chiral compounds in multiple mobile phases. High stability and sample capacities were observed on this polymeric
chiral stationary phase. Mobile phase components and additives affected chiral separation greatly. This new synthetic chiral
stationary phase is complementary to two other related commercially available CSPs: the P-CAP and P-CAP-DP columns. Interactions
between the chiral stationary phase and analytes that lead to retention and chiral recognition include hydrogen bonding, dipolar,
and π–π interactions. Repulsive (steric) interactions also contribute to chiral recognition.
Figure LC chromatograms showing the analytical (blue) and preparative (red) separations of N-(3,5-dinitrobenzoylleucine) enantiomers on a new synthetic polymeric chiral stationary phase 相似文献
12.
Careri M Costa A Elviri L Lagos JB Mangia A Terenghi M Cereti A Garoffo LP 《Analytical and bioanalytical chemistry》2007,389(6):1901-1907
A liquid chromatography–electrospray-tandem mass spectrometry (LC–ESI-MS–MS) method based on the detection of biomarker peptides
from allergenic proteins was devised for confirming and quantifying peanut allergens in foods. Peptides obtained from tryptic
digestion of Ara h 2 and Ara h 3/4 proteins were identified and characterized by LC–MS and LC–MS–MS with a quadrupole-time
of flight mass analyzer. Four peptides were chosen and investigated as biomarkers taking into account their selectivity, the
absence of missed cleavages, the uniform distribution in the Ara h 2 and Ara h 3/4 protein isoforms together with their spectral
features under ESI-MS–MS conditions, and good repeatability of LC retention time. Because of the different expression levels,
the selection of two different allergenic proteins was proved to be useful in the identification and univocal confirmation
of the presence of peanuts in foodstuffs. Using rice crispy and chocolate-based snacks as model food matrix, an LC–MS–MS method
with triple quadrupole mass analyzer allowed good detection limits to be obtained for Ara h2 (5 μg protein g−1 matrix) and Ara h3/4 (1 μg protein g−1 matrix). Linearity of the method was established in the 10–200 μg g−1 range of peanut proteins in the food matrix investigated. Method selectivity was demonstrated by analyzing tree nuts (almonds,
pecan nuts, hazelnuts, walnuts) and food ingredients such as milk, soy beans, chocolate, cornflakes, and rice crispy.
Figure ESI-QTOF-MS mass spectrum of Ara h3/4 triptig digest 相似文献
13.
A new vapor generation system for mercury (Hg) species based on the irradiation of mercaptoethanol (ME) with UV was developed
to provide an effective sample introduction unit for atomic fluorescence spectrometry (AFS). Preliminary investigations of
the mechanism of this novel vapor generation system were based on GC–MS and FT–IR studies. Under optimum conditions, the limits
of determination for inorganic divalence mercury and methyl mercury were 60 and 50 pg mL−1, respectively. Certified reference materials (BCR 463 tuna fish and BCR 580 estuarine sediment) were used to validate this
new method, and the results agreed well with certified values. This new system provides an attractive alternative method of
chemical vapor generation (CVG) of mercury species compared to other developed CVG systems (for example, the traditional KBH4/NaOH–acid system). To our knowledge, this is the first systematic report on UV/ME-based Hg species vapor generation and the
determination of total and methyl Hg in environmental and biological samples using UV/ME–AFS.
Figure A new vapor generation system for mercury species using mercaptoethanol under UV irradiation was developed as an effective
sample introduction unit for atomic fluorescence spectrometry 相似文献
14.
Tribalat L Paisse O Dessalces G Grenier-Loustalot MF 《Analytical and bioanalytical chemistry》2006,386(7-8):2161-2168
In the framework of developing analyses for exogenous contaminants in food matrices such as honey, we have compared data obtained
by high-performance liquid chromatography coupled with mass spectrometry (LC–MS) to those provided by high-performance liquid
chromatography and tandem mass spectrometry (LC–MS–MS). Initial results obtained with LC–MS showed that the technique lacked
selectivity, which is why the method was validated by LC–MS–MS. This method involves a solid-phase extraction (SPE) of nitrofuran
metabolites and nitrofuran parent drugs, a derivatization by 2-nitrobenzaldehyde for 17 h, and finally a clean-up by SPE.
The data obtained show that the limits of detection varied between 0.2 and 0.6 μg kg−1 for the metabolites and between 1 and 2 μg kg−1 for nitrofuran parent drugs. The method was applied to different flower honeys. The results showed that nitrofurans (used
as antibiotics) are consistently present in this matrix, the predominant compound being furazolidone.
Figure Working bees 相似文献
15.
D'Ulivo A Battistini SS Pitzalis E Zamboni R Mester Z Sturgeon RE 《Analytical and bioanalytical chemistry》2007,388(4):783-791
The effect of mM concentrations of K3[Fe(CN)6], Fe(III), Mo(VI), KSCN and KMnO4 on the generation of BiH3 by the reaction of 0.2–10 μg ml−1 Bi(III) with 0.2 M tetrahydroborate(III) at 1 M acidity (HCl or HNO3) was investigated. Chemical vapour generation (CVG) of BiH3 was investigated by atomic absorption spectrometry using a continuous flow reaction system (CF–CVG–AAS) and different mixing
sequences and reagent reaction times. Gas chromatography–mass spectrometry (GC–MS) was employed in batch generation experiments
with NaBD4. In the absence of additives, the formation of Bi0 at high concentrations of Bi(III) caused rollover of calibration curves and limited the linear range to less than 1 μg ml−1 Bi(III). In the presence of additives, the formation of Bi0 was not observed and the linear range was increased to 5 μg ml−1 of Bi(III) while rollover was completely removed. GC–MS experiments indicated that the presence of additives did not affect
the direct transfer of H from boron to bismuth. Experiments with CF–CVG–AAS and different mixing sequences and reagent reaction
times suggest that additives act by preventing the formation of Bi0 through the formation of reaction intermediates which evolve towards the formation of BiH3 at elevated Bi(III)/NaBH4 ratios.
相似文献
16.
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
17.
An X-ray fluorescence method (XRF) is presented that allowed low detection limits (at the 0.1–23 ng mL−1 level) to be obtained for Cr, Mn, Fe, Ni, Zn, Sr, Pb, Bi and Br in water. The samples were prepared using a thin layer method. Trace elements were determined via the calibration curve and standard addition. Absorption effects and inhomogenities in prepared samples were checked for using the emission–transmission method and internal standards, respectively. The results from the XRF method were compared with the results from the inductively coupled plasma atomic emission spectrometry method.
相似文献
18.
An aptamer-based label-free approach to hemin recognition and DNA assay using capillary electrophoresis with chemiluminescence
detection is introduced here. Two guanine-rich DNA aptamers were used as the recognition element and target DNA, respectively.
In the presence of potassium ions, the two aptamers folded into the G-quartet structures, binding hemin with high specificity
and affinity. Based on the G-quartet–hemin interactions, the ligand molecule was specifically recognized with a K
d ≈ 73 nM, and the target DNA could be detected at 0.1 μM. In phosphate buffer of pH 11.0, hemin catalyzed the H2O2-mediated oxidation of luminol to generate strong chemiluminescence signal; thus the target molecule itself served as an indicator
for the molecule–aptamer interaction, which made the labeling and/or modification of aptamers or target molecules unnecessary.
This label-free method for molecular recognition and DNA detection is therefore simple, easy, and effective.
Figure A label-free approach to aptamer-based hemin recognition and DNA detection is introduced, which gives great potential for
using a small molecule itself as the indicator for molecular recognition and DNA detection thereby avoiding any labeling or
modification step 相似文献
19.
A rapid, specific, and sensitive method has been developed using molecularly imprinted polymers (MIPs) as solid-phase extraction
sorbents for extraction of trace tetracycline antibiotics (TCs) in foodstuffs. MIPs were prepared by precipitation polymerization
using tetracycline as the template. Under the optimal condition, the imprinting factors for MIPs were 4.1 (oxytetracycline),
7.0 (tetracycline), 7.4 (chlortetracycline), 7.7 (doxycycline), respectively. Furthermore, the performance of MIPs as solid-phase
extraction sorbents was evaluated and high extraction efficiency of molecularly imprinted solid-phase extraction (MISPE) procedure
was demonstrated. Compared with commercial sorbents, MISPE gave a better cleanup efficiency than C18 cartridge and a higher
recovery than Oasis HLB cartridge. Finally, the method of liquid chromatography–tandem mass spectrometry coupled with molecular-imprinted
solid-phase extraction was validated in real samples including lobster, duck, honey, and egg. The spiked recoveries of TCs
ranged from 94.51% to 103.0%. The limits of detection were in the range of 0.1–0.3 μg kg−1.
Chromatograms obtained by direct injection of the spiked egg extracts (5 × 10-3 mmol L−1) and purification with MISPE 相似文献
20.
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