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1.
Kahina Si-Ahmed Fairouz Tazerouti Ahmed Y. Badjah-Hadj-Ahmed 《Analytical and bioanalytical chemistry》2009,395(2):507-518
In order to study the effect of the nature and the length of the spacer, three mixed 10-undecenoate/phenylcarbamate derivatives
of β-cyclodextrin have been prepared and linked to allylsilica gel by means of a radical reaction. The chiral recognition
ability of the resulting materials, when used as liquid chromatography chiral stationary phases (CSPs), was evaluated using
heptane and either 2-propanol or chloroform as organic mobile-phase modifiers. A large variety of racemic compounds have been
separated successfully on these CSPs (mainly pharmaceuticals and herbicides). Optimization of these separations was discussed
in terms of mobile-phase composition and structural patterns of the injected analytes. The efficiencies of the three prepared
materials were compared to those of previously described perphenylated-β-cyclodextrin column and to analogous cellulose derivative-based
CSPs.
Schematic illustration of the b-cyclodextrin/mandelic acid inclusion complex 相似文献
2.
D. Brynn Hibbert Danielle Blackmore Jianfeng Li Diako Ebrahimi Michael Collins Sasha Vujic Paul Gavoyannis 《Analytical and bioanalytical chemistry》2010,396(2):765-773
The probability density functions of amount ratios of compounds (total codeine/total morphine, 6-monoacetylemorphine/total
morphine, papaverine/total morphine, and noscapine/total morphine) from the analysis of seized heroin, originating from known
world regions (South East Asia, South West Asia, South America, Mexico) allows calculation of likelihood ratios for ‘unknown’
samples. Application of Bayes Theorem with a suitable prior probability, for example the frequency of a particular region
in the database, leads to the probability that a particular profile comes from a given target region. Data from 2549 seizures
of heroin at Australia’s border illustrates the method, and results are compared with simple HS1 ratio approaches for assigning
geographical origin. The method can be implemented in a spreadsheet and gives more refined intelligence of the origins of
seized drugs than simple ranges.
相似文献
3.
Alexander Fabian Le Blanc Christiane Albrecht Tomas Bonn Peter Fechner Günther Proll Florian Pr?ll Mats Carlquist Günter Gauglitz 《Analytical and bioanalytical chemistry》2009,395(6):1769-1776
A novel combined procedure for estrogen-affinity purification and labelling of estrogen receptor α ligand-binding domain with
Cy™ 5.5 cystein reactive dye was established. By using this procedure, mainly functional proteins are recovered. It can be
easily adapted to a large variety of other proteins for which ligand-coated affinity materials are available. The labelled
receptor was used in a total internal reflection fluorescence-based binding inhibition assay for determination of the impact
of pollutants in river water on the receptor. The great advantage compared to conventional methods is that the total effect
on the receptor is measured instead of concentrations of single compounds and that even currently unknown ligands are found
as well. Therefore, the obtained signal is related to the response of the organism, which is exposed to the water. The limit
of detection was found to be 0.139 nM of estradiol equivalents. The assay also provides a highly sensitive tool for pharmaceutical
research and can be adapted to diagnostic applications.
相似文献
4.
Alain Walcarius 《Analytical and bioanalytical chemistry》2010,396(1):261-272
Nano- and/or macrostructuring of electrode surfaces has recently emerged as a powerful method of improving the performances
of electrochemical devices by enhancing both molecular accessibility and rapid mass transport via diffusion, by increasing
the electroactive surface area in comparison to the geometric one, and/or by providing confinement platforms for hosting suitable
reagents. This brief overview highlights how template technology offers advantages in terms of designing new types of porous
electrodes—mostly based on thin films, and functionalized or not—and discusses their use in analytical chemistry via some
recent examples from the literature on electrochemical sensors and biosensors.
相似文献
5.
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
6.
András Gergely Péter Horváth György Szász Gábor Veress 《Analytical and bioanalytical chemistry》2009,394(8):2105-2109
A three-step gradient reversed-phase high-performance liquid chromatography (RP-HPLC) method was developed for the separation
of dehydroepiandrosterone (DHEA), its sulfate ester (DHEA-S), its three C7-oxidized metabolites (7αOH-DHEA, 7βOH-DHEA, 7-keto-DHEA),
and its biosynthetic congeners (androstenedione, testosterone, estradiol, pregnenolone). This new method allows the quantitative
characterization of DHEA metabolism and biosynthetic transformation under given physiological, pathological, or therapeutically
influenced circumstances. Tetrahydrofuran probably acts as a proton acceptor coadsorbent, while isopropanol behaves as a proton
donor during the separation of testosterone, estradiol, and the stereoisomers of 7-OH-DHEA.
Figure Optimized gradient RP-HPLC results in full separation of DHEA from its biosynthetic congeners and metabolites 相似文献
7.
Nan Li Hui Tang Hongwei Gai Xiuling Dong Qi Wang Edward S. Yeung 《Analytical and bioanalytical chemistry》2009,394(7):1879-1885
Determination of protein surface excess is an important way of evaluating the properties of biomaterials and the characteristics
of biosensors. A single-molecule counting method is presented that uses a standard fluorescence microscope to measure coverage
of a liquid/solid interface by adsorbed proteins. The extremely low surface excess of lysozyme and bovine serum albumin (BSA),
in a bulk concentration range from 0.3 nmol L−1 (0.02 μg mL−1) to 3 nmol L−1 (0.2 μg mL−1), were measured by recording the counts of spatially isolated single molecules on either hydrophilic (glass) or hydrophobic
(polydimethylsiloxane, PDMS) surfaces at different pH. The differences observed in amounts of adsorbed proteins under different
experimental conditions can be qualitatively explained by the combined interactions of electrostatic and hydrophobic forces.
This, in turn, implies that single-molecule counting is an effective way of measuring surface coverage at a liquid/solid interface.
Figure Adsorption fraction of proteins on different surfaces changed with pH. 相似文献
8.
S. Pous-Torres J. R. Torres-Lapasió J. J. Baeza-Baeza M. C. García-álvarez-Coque 《Analytical and bioanalytical chemistry》2009,394(2):625-636
An indirect method for dead time (t
0) estimation in reversed-phase liquid chromatography, based on a relationship between retention time and organic solvent content,
is proposed. The method processes the retention data obtained in experimental designs. In order to get more general validity
and enhance the accuracy, the information from several compounds is used altogether in an alternating regression fashion.
The method was applied to nitrosamines, alkylbenzenes, phenols, benzene derivatives, polycyclic aromatic hydrocarbons and
β-blockers, among other compounds, chromatographed in a cyano and several C18 columns. A comprehensive validation was carried
out by comparing the results with those provided by the injection of markers, the observation of the solvent front and the
homologous series method. It was also found that different groups of compounds yielded the same t
0 value with the same column, which was verified in different solvent composition windows. The method allows improved models
useful for optimisation or for other purposes, since t
0 can be estimated with the retention data of the target solutes.
相似文献
9.
Rudolf Tuckermann Ljiljana Puskar Mahta Zavabeti Ryo Sekine Don McNaughton 《Analytical and bioanalytical chemistry》2009,394(5):1433-1441
An experimental apparatus combining Raman spectroscopy with acoustic levitation, Raman acoustic levitation spectroscopy (RALS),
is investigated in the field of physical and chemical analytics. Whereas acoustic levitation enables the contactless handling
of microsized samples, Raman spectroscopy offers the advantage of a noninvasive method without complex sample preparation.
After carrying out some systematic tests to probe the sensitivity of the technique to drop size, shape, and position, RALS
has been successfully applied in monitoring sample dilution and preconcentration, evaporation, crystallization, an acid–base
reaction, and analytes in a surface-enhanced Raman spectroscopy colloidal suspension.
Figure We have systematically investigated the analytical potential of Raman spectroscopy of samples in acoustically levitated drops. 相似文献
10.
Sara Wallin Anna Pettersson Henric Östmark Alison Hobro 《Analytical and bioanalytical chemistry》2009,395(2):259-274
A review of standoff detection technologies for explosives has been made. The review is focused on trace detection methods
(methods aiming to detect traces from handling explosives or the vapours surrounding an explosive charge due to the vapour
pressure of the explosive) rather than bulk detection methods (methods aiming to detect the bulk explosive charge). The requirements
for standoff detection technologies are discussed. The technologies discussed are mostly laser-based trace detection technologies,
such as laser-induced-breakdown spectroscopy, Raman spectroscopy, laser-induced-fluorescence spectroscopy and IR spectroscopy
but the bulk detection technologies millimetre wave imaging and terahertz spectroscopy are also discussed as a complement
to the laser-based methods. The review includes novel techniques, not yet tested in realistic environments, more mature technologies
which have been tested outdoors in realistic environments as well as the most mature millimetre wave imaging technique.
Figure Standoff detection and identification is one of the most wanted capabilities 相似文献
11.
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
12.
A novel microextraction method is introduced based on dispersive liquid–liquid microextraction (DLLME) in which an in situ
metathesis reaction forms a water-immiscible ionic liquid (IL) that preconcentrates aromatic compounds from water followed
by separation using high-performance liquid chromatography. The simultaneous extraction and metathesis reaction forming the
IL-based extraction phase greatly decreases the extraction time as well as provides higher enrichment factors compared to
traditional IL DLLME and direct immersion single-drop microextraction methods. The effects of various experimental parameters
including type of extraction solvent, extraction and centrifugation times, volume of the sample solution, extraction IL and
exchanging reagent, and addition of organic solvent and salt were investigated and optimized for the extraction of 13 aromatic
compounds. The limits of detection for seven polycyclic aromatic hydrocarbons varied from 0.02 to 0.3 μg L−1. The method reproducibility produced relative standard deviation values ranging from 3.7% to 6.9%. Four real water samples
including tap water, well water, creek water, and river water were analyzed and yielded recoveries ranging from 84% to 115%.
相似文献
13.
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
14.
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
15.
Christine Mousty 《Analytical and bioanalytical chemistry》2010,396(1):315-325
Two-dimensional layered inorganic solids, such as cationic clays and layered double hydroxides (LDHs), also defined as anionic
clays, have open structures which are favourable for interactions with enzymes and which intercalate redox mediators. This
review aims to show the interest in clays and LDHs as suitable host matrices likely to immobilize enzymes onto electrode surfaces
for biosensing applications. It is meant to provide an overview of the various types of electrochemical biosensors that have
been developed with these 2D layered materials, along with significant advances over the last several years. The different
biosensor configurations and their specific transduction procedures are discussed.
相似文献
16.
This work reports the development of a bienzyme system consisting of salicylate hydroxylase (SHL) and nitrate reductase (NaR)
for the electrochemical determination of nitrate. This method measures the concentration of nitrate directly under ambient
air without suffering from oxygen interferences. The determination is based on the detection of NADH consumption, and the
principle is as follows: NADH initiates the irreversible decarboxylation and hydroxylation of salicylate by SHL in the presence
of oxygen to produce catechol, which results in a detectable signal due to its oxidation at the working electrode; the second
enzyme, NaR, in the presence of nitrate, reduced the availability of NADH, and consequently, the current difference after
the injection of nitrate is proportional to its concentration. This method shows high performance characteristics for nitrate
determination with a broad detection range between 10 μM and 1,000 μM, a short measuring time of around 5 min, and a simple
operation without sample pretreatment by inert gas purge or oxygen scavenger.
Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible to authorized users. 相似文献
Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible to authorized users. 相似文献
17.
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
18.
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
19.
Alvarado Tarun Norihiko Hayazawa Satoshi Kawata 《Analytical and bioanalytical chemistry》2009,394(7):1775-1785
Tip-enhanced Raman spectroscopy (TERS), which utilizes the strong localized optical field generated at the apex of a metallic
tip when illuminated, has been shown to successfully probe the vibrational spectrum of today’s and tomorrow’s state-of-the-art
silicon and next-generation semiconductor devices, such as quantum dots. Collecting and analyzing the vibrational spectrum
not only aids in material identification but also provides insight into strain distributions in semiconductors. Here, the
potential of TERS for nanoscale characterization of strain in silicon devices is reviewed. Emphasis will be placed on the
key challenges of obtaining spectroscopic images of strain in actual strained silicon devices.
Figure Figure Concept of Tip Enhanced Raman Spectroscopy (TERS), which utilizes the strong localized optical field generated at the
apex of a metallic tip when illuminated. TERS has been demonstrated to successfully probe the vibrational spectrum of today’s
and tomorrow’s state-of-the-art silicon and next generation semiconductor devices 相似文献