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1.
Heike Traub Markus W?lle Joachim Koch Ulrich Panne Ralf Matschat Heinrich Kipphardt Detlef Günther 《Analytical and bioanalytical chemistry》2009,395(5):1471-1480
Solution-doped metal powder pellets as well as aspirated liquids were used as calibration samples to analyze pure copper and
zinc certified reference materials (CRMs) by femtosecond laser ablation ICP-MS. It was demonstrated that calibration by copper
pellets resulted in relative deviations up to 20%, whereas fs-LA-ICP-MS among copper-based CRMs led to inaccuracies in the
same range unless nominal mass fractions were chosen to be <3 mg/kg. Calibration by zinc pellets generally provided better
accuracy. Depending on the analyte considered, deviations below 10% were obtained even for mass fractions close to the limit
of quantification. Our data, therefore, indicate solution-doped metal powder pellets to be suitable as calibration samples
for fs-LA-ICP-MS of metals. Furthermore, the utilization of liquid standards for calibration was found to result in stronger
deviations of up to 50% for both copper and zinc samples which, in addition, turned out to be dependent on the plasma conditions.
相似文献
2.
Veronica M. T. Lattanzio Michele Solfrizzo Angelo Visconti 《Analytical and bioanalytical chemistry》2009,395(5):1325-1334
The selective enzymatic deacetylation of T-2 toxin to give HT-2 toxin has been investigated in aqueous crude extracts of different
cereals and exploited to develop an analytical method for the determination of the sum of T-2 and HT-2 toxins. The method
has been validated for the analysis of total T-2 and HT-2 toxins in maize, wheat, and oats, showing recoveries from 72 to
97% for maize, from 67 to 84% for wheat, and from 61% to 87% for oats, at spiking levels of 20–400 μg/kg, with relative standard
deviation lower than 10%. Liquid chromatography-tandem mass spectrometry was used for quantitative toxin determination. The
potential biological role of this enzymatic conversion and its perspectives for application in the development of antibody-based
analytical techniques are discussed.
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3.
Núria Serrano José Manuel Díaz-Cruz Cristina Ariño Miquel Esteban 《Analytical and bioanalytical chemistry》2010,396(3):1365-1369
A commercially available screen-printed carbon electrode coated with an ex situ deposited bismuth film (BiSPCE) has been applied
to the determination of Pb(II) and Zn(II) ions in tap water (Barcelona water distribution network) by means of stripping voltammetry
(SV) and stripping chronopotentiometry (SCP). A good reproducibility of the measurements and a satisfactory agreement between
SV and SCP data were observed for both heavy metal ions. Although, in principle, the procedure could be also suited to the
determination of Cd(II), this species was not detected. The results were also consistent with the routine ICP-OES measurements
of the water distribution company, thus confirming the potential usefulness of such BiSPCE disposable devices for the analysis
of heavy metals in natural waters.
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4.
Determining sulfamonomethoxine and its acetyl/hydroxyl metabolites in chicken plasma under organic solvent-free conditions 总被引:1,自引:0,他引:1
Furusawa N 《Analytical and bioanalytical chemistry》2006,385(8):1570-1574
A quantitative technique is described for a sample preparation followed by high performance liquid chromatography method for
the simultaneous determination of sulfamonomethoxine and its metabolites, N
4-acetyl SMM and 2,6-dihydroxy SMM, in chicken plasma. The average recoveries, analytical total time, and limits of quantitation
were ≥80% (relative standard deviations (SD) ≤6%), <30 min sample-1 (12 samples in 2 h), and ≤0.09 μg ml−1, respectively. The procedure, performed under 100% aqueous conditions, uses no organic solvents and toxic reagents at all
and is, therefore, harmless to the environment and humans.
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5.
Zhang Y Wu HL Xia AL Zhu SH Han QJ Yu RQ 《Analytical and bioanalytical chemistry》2006,386(6):1741-1748
In this study a new spectrofluorimetric method for the direct determination of metoprolol in human plasma is presented and
discussed. It is based on the use of fluorescence excitation–emission matrices (EEMs) and second-order calibration performed
with parallel factor analysis (PARAFAC) or alternating trilinear decomposition (ATLD). This methodology enables accurate and
reliable discrimination of the analyte signal, even in the presence of unknown and uncalibrated fluorescent component(s),
which is often referred to as the second-order advantage. No separation or sample pretreatment steps were required. Satisfactory
results were obtained. Metoprolol recoveries in plasma were determined as 87±2% and 90±4% with PARAFAC and ATLD, respectively.
All RSD values of intra- and interday assays were below 5%.
Figure A three-dimensional plot of EEMs for a plasma sample and metoprolol solution 相似文献
6.
Masako Fujiwara Takeshi Kobayashi Takahiro Jomori Yutaka Maruyama Yoshitomo Oka Hiroshi Sekino Yutaka Imai Kazuhisa Takeuchi 《Analytical and bioanalytical chemistry》2009,394(6):1655-1660
1H NMR spectroscopic and pattern recognition-based methods (NMR-PR) were applied to the metabolic profiling studies on hemodialysis
(HD). Plasma samples were collected from 37 patients before and after HD and measured by 600 MHz NMR spectroscopy. Each spectrum
was data-processed and subjected to principal component analysis for pattern recognition. Spectral patterns of plasma between
pre- and post-dialyses were clearly discriminated, together with significant fluctuations in the levels of creatinine, trimethylamine-N-oxide, glucose, lactate, and acetate, which were quantitated. We have first observed the significant elevation of lactate
levels in post-dialysis plasma. The present study has demonstrated the high feasibility of NMR-PR method for monitoring the
dialysis condition and comprehensive profiling of the change of low-molecular-weight metabolites in HD.
Figure PCA for 1H NMR spectra of plasma from HD patients 相似文献
7.
A dual sample introduction system was explored for volatile hydride generation in inductively coupled plasma–optical emission
spectrometry (ICP–OES) performed in the radially viewed mode. The system consists of two pneumatic nebulizers connected to
the conventional spray chamber of the instrument via a simple adaptor. This configuration permits hydride generation but still
allows other elements to be determined by pneumatic nebulization. This work was focused on the optimization of the plasma
operating conditions for the determination of As, Hg, Sb and Se and other elements. The excitation conditions of the ICP–OES
instrument operated with the dual sample introduction system were also explored. Results showed that the analytical performance
of the dual system for the determination of As, Hg, Sb and Se was superior to those of conventional nebulization systems.
The dual system also enabled the determination of elements that do not form volatile hydrides, but with less sensitivity than
conventional nebulization systems. An evaluation of the plasma robustness showed that the gases generated in the hydride reactions
did not significantly affect the plasma discharge. Similar to conventional hydride generation techniques, the analysis was
susceptible to nonspectroscopic interferences produced by transition metals. Finally, the applicability of the dual nebulization
system to practical ICP–OES studies was demonstrated by determining the trace elements in an oyster tissue standard reference
material.
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8.
A nonradioactive 31P nuclear magnetic resonance (NMR) spectroscopy protocol has been developed and used to investigate in vitro autophosphorylation of insulin receptors. Optimum experimental conditions have been explored, and the effects of Mn2+ and phosphocreatine (PCr) on the determination of the phosphorylation reaction have been assayed. The method was used to monitor the time courses of the phosphorylation reaction in solution. The results from this NMR study were in agreement with observations of insulin receptor phosphorylation made by using Western blotting.
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9.
Berchmans S Vergheese TM Kavitha AL Veerakumar M Yegnaraman V 《Analytical and bioanalytical chemistry》2008,390(3):939-946
The present work describes, for the first time, in situ electrochemical preparation of dendrimer-encapsulated Cu nanoparticles
using a self-assembled monolayer of fourth-generation amine-terminated polyamidoamine (PAMAM) dendrimer as the template. Atomic
force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) studies of the modified surface confirmed the presence of
Cu nanoparticles entrapped in dendrimer film. Au electrode modified with a monolayer of the dendrimer enables preconcentration
and subsequent voltammetric detection of Cu2+ at picomolar concentrations. Further, Cu nanoparticles in the dendrimer monolayer could be electrochemically derivatised
to Cu hexacyanoferrate, which exhibits specific crystal planes, unlike the random distribution of crystal planes in bulk-formed
Cu hexacyanoferrate, which is another catalytically active material for sensor applications.
Figure Electrochemical preparation of copper–dendrimer nanocomposite 相似文献
10.
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
11.
ágnes Varga Gergely Gyetvai Lívia Nagy Géza Nagy 《Analytical and bioanalytical chemistry》2009,394(7):1955-1963
The diffusion coefficient of glucose in different media is an important parameter in life sciences, as well as in biotechnology
and microbiology. In this work a simple, fast method is proposed that is based on the electrochemical time of flight principle.
In most of the earlier time of flight experiments performed, a constant flight distance was applied. In the present work a
scanning electrochemical microscope (SECM) was applied as a measuring tool. With use of the SECM, the flying distance could
be changed with high precision, making measurements with several flight distances more accurate and reliable values could
be obtained for solutions as well as for gels. The conventional voltammetric methods are not applicable for glucose detection.
In our work electrocatalytic copper oxide coated copper microelectrodes and micro-sized amperometric enzyme sensors were used
as detectors, while microdroplet-ejecting pneumatically driven micropipettes were used as a source.
Figure Experimental set up for SCEM-TOF diffusion coefficient measurements
Presented at the 9th International Symposium on Instrumental Analysis, Pécs, Hungary, 29 July-2 August 2008 相似文献
12.
A novel method named a wavelet packet transform based Elman recurrent neural network (WPTERNN) was proposed for the simultaneous
UV–visible spectrometric determination of Cu(II), Cd(II) and Zn(II). This method combined wavelet packet denoising with an
Elman recurrent neural network. A wavelet packet transform was applied to perform data compression, to extract relevant information,
and to eliminate noise and collinearity. An Elman recurrent network was applied for nonlinear multivariate calibration. In
this case, using trials, the kind of wavelet function, the decomposition level, and the number of hidden nodes for the WPTERNN
method were selected as Daubechies 14, 3, and 8, respectively. A program (PWPTERNN) was designed that could perform the simultaneous
determination of Cu(II), Cd(II) and Zn(II). The relative standard errors of prediction (RSEP) obtained for all components
using WPTERNN, a Elman recurrent neural network (ERNN), partial least squares (PLS), principal component regression (PCR),
Fourier transform based PCR (FTPCR), and multivariate linear regression (MLR) were compared. Experimental results demonstrated
that the WPTERRN method was successful even where there was severe overlap of spectra. The results obtained from an additional
test case also demonstrated that the WPTERNN method performed very well.
Figure The part of WP coefficients obtained by wavelet packet transforms 相似文献
13.
Liming Wang Yu-Feng Li Liangjun Zhou Ying Liu Li Meng Ke Zhang Xiaochun Wu Lili Zhang Bai Li Chunying Chen 《Analytical and bioanalytical chemistry》2010,396(3):1105-1114
Integrated analytical techniques were used to study the tissue distribution and structural information of gold nanorods (Au
NRs) in Sprague-Dawley rats through tail intravenous injection. Before in vivo experiments were conducted, careful characterization
of Au NRs was performed. The zeta potential proved that adsorption of bovine serum albumin on Au NRs turned the surface charges
from positive to negative as in an in vitro simulation. The biodistribution of Au NRs was investigated quantitatively by inductively
coupled plasma mass spectrometry at different time points after injection. As target tissues, both liver and spleen were chosen
to further demonstrate the intracellular localization of Au NRs by the combination of transmission electron microscopy and
energy-dispersive X-ray spectroscopy. Moreover, synchrotron-radiation-based X-ray absorption spectroscopy was employed and
it was observed that long-term retention of Au NRs in liver and spleen did not induce obvious changes in the oxidation states
of gold. Therefore, the present systematic method can provide important information about the fates of Au NRs in vivo and
can also be extended to study the biological effects of other metallic nanomaterials in the future.
相似文献
14.
Small-volume fiber-optic evanescent-wave absorption sensor for nitrite determination 总被引:1,自引:0,他引:1
Yan Xiong Dao-qian Zhu Chun-feng Duan Jian-wei Wang Ya-feng Guan 《Analytical and bioanalytical chemistry》2010,396(2):943-948
A novel small-volume fiber-optic evanescent-wave absorption sensor based on the Griess–Ilosvay reaction has been developed
and evaluated for nitrite determination. The sensor was constructed by inserting a decladded optical fiber into a transparent
capillary to form an annular column microchannel. The Evanescent wave (EW) field produced on the optical fiber core surface
penetrated into the surrounding medium and interacted with the azo dye, which was generated by the reaction of nitrite and
nitrite-sensitive reagents. The detector was designed to be parallel to the axis of the optical fiber. The defined absorbance
was linear with the concentration of nitrite in the range from 0.05 to 10 mg L−1, and the detection limit was 0.02 mg L−1 (3σ) with the relative standard deviation (RSD) of 2.6% (n = 8). The present sensor was successfully used to determine nitrite in real samples of mineral water, tap water, rain water,
and seawater. The results were consistent with the data obtained by standard spectrophotometric method, showing potential
of the proposed sensor for practical application.
相似文献
15.
Yveline Henchoz Bruno Bard Davy Guillarme Pierre-Alain Carrupt Jean-Luc Veuthey Sophie Martel 《Analytical and bioanalytical chemistry》2009,394(3):707-729
The measurement of physicochemical properties at an early phase of drug discovery and development is crucial to reduce attrition
rates due to poor biopharmaceutical properties. Among these properties, ionization, lipophilicity, solubility and permeability
are mandatory to predict the pharmacokinetic behavior of NCEs (new chemical entities). Due to the high number of NCEs, the
analytical tools used to measure these properties are automated and progressively adapted to high-throughput technologies.
The present review is dedicated to experimental methods applied in the early drug discovery process for the determination
of solubility, ionization constants, lipophilicity and permeability of small molecules. The principles and experimental conditions
of the different methods are described, and important enhancements in terms of throughput are highlighted.
Figure Scheme of the Drug Research Process. 相似文献
16.
Xiaoshan Zhu Dayue Duan Steen Madsen Nelson G. Publicover 《Analytical and bioanalytical chemistry》2010,396(3):1345-1353
In this work, the compatibility of quantum dots (QDs) with immunobuffers was studied by investigating the fluorescence stability
of QDs in immunobuffers (in this research immunobuffers were defined as buffers for immunoaffinity binding or separation).
Experimentally, the fluorescence signals of QDs with different surface chemistries (amine-terminated, streptavidin-coated,
or antibody-conjugated) in commonly used immunobuffers were monitored versus time. The effect of some buffer composition on
the compatibility of QDs with these buffers was also explored. Based on experimental data, the QD compatibility with these
buffers is summarized, and it is found that a trace amount of bovine serum albumin added to most of these buffers helps QDs
to achieve compatibility with them. Moreover, with QD as fluorescence label and C-reactive protein as a model analyte, a magnetic
bead-based assay was performed using compatible and incompatible QD–immunobuffer systems. It is shown that compatible QD–immunobuffer
systems can be used to achieve a higher assay signal/background ratio.
相似文献
17.
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
18.
C. R. Dockery A. R. Stefan A. A. Nieuwland S. N. Roberson B. M. Baguley J. E. Hendrix S. L. Morgan 《Analytical and bioanalytical chemistry》2009,394(8):2095-2103
Systematic designed experiments were employed to find the optimum conditions for extraction of direct, reactive, and vat dyes
from cotton fibers prior to forensic characterization. Automated microextractions were coupled with measurements of extraction
efficiencies on a microplate reader UV–visible spectrophotometer to enable rapid screening of extraction efficiency as a function
of solvent composition. Solvent extraction conditions were also developed to be compatible with subsequent forensic characterization
of extracted dyes by capillary electrophoresis with UV–visible diode array detection. The capillary electrophoresis electrolyte
successfully used in this work consists of 5 mM ammonium acetate in 40:60 acetonitrile–water at pH 9.3, with the addition
of sodium dithionite reducing agent to facilitate analysis of vat dyes. The ultimate goal of these research efforts is enhanced
discrimination of trace fiber evidence by analysis of extracted dyes.
Figure Fitted absorbance response surface for extraction of a direct dye, C. I. yellow 58, using a ternary solvent system. 相似文献
19.
External μPIXE has been used for characterisation of small samples of varnish from historical violins, and pieces of varnished
wood from historical and modern stringed instruments. To obtain spatially resolved information about the distribution of elements
across the varnish layers single-spot analysis, line-scans, and area-mapping were performed. Local resolution of approximately
20 μm was obtained from the 3 MeV, 1 nA proton micro-probe. Results from simultaneous multi-element determination of Na, Mg,
Al, Si, P, S, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Br, Rb, Sr, Ag, Cd, Sn, Ba, and Pb in historical varnishes are
presented. Semi-quantitative evaluation of line-scans recorded on diverse historical varnishes is reported. The applied method
is discussed in detail and the results obtained are critically reviewed and compared with those in the literature.
相似文献
20.
A colloidal synthesis method was developed to produce face centered cubic (fcc) Cu nanoparticles in the presence of surfactants
in an organic solvent under an Ar environment. Various synthetic conditions were explored to control the size of the as-prepared
nanoparticles by changing the precursor, varying the amount of surfactants, and tuning the reaction temperature. Transmission
electron microscopy (TEM), selected-area electron diffraction, and high-resolution TEM were used as the main characterization
tools. Upon exposure to air, these nanoparticles are oxidized at different levels depending on their sizes: (1) an inhomogeneous
layer of fcc Cu2O forms at the surface of Cu nanoparticles (about 30 nm); (2) Cu nanoparticles (about 5 nm) are immediately oxidized into
fcc Cu2O nanoparticles (about 6 nm). The occurrence of these different levels of oxidization demonstrates the reactive nature of
Cu nanoparticles and the effect of size on their reactivity. Furthermore, utilization of their chemical reactivity and conversion
of spherical Cu nanoparticles into CuS nanoplates through the nanoscale Kirkendall effect were demonstrated. The oxidization
and sulfidation of Cu nanoparticles were compared. Different diffusion and growth behaviors were involved in these two chemical
transformations, resulting in the formation of isotropic Cu2O nanoparticles during oxidization and anisotropic CuS nanoplates during sulfidation.
相似文献