共查询到20条相似文献,搜索用时 15 毫秒
1.
Kevin A. Wepasnick Billy A. Smith Julie L. Bitter D. Howard Fairbrother 《Analytical and bioanalytical chemistry》2010,396(3):1003-1014
To utilize carbon nanotubes (CNTs) in various commercial and scientific applications, the graphene sheets that comprise CNT
surfaces are often modified to tailor properties, such as dispersion. In this article, we provide a critical review of the
techniques used to explore the chemical and structural characteristics of CNTs modified by covalent surface modification strategies
that involve the direct incorporation of specific elements and inorganic or organic functional groups into the graphene sidewalls.
Using examples from the literature, we discuss not only the popular techniques such as TEM, XPS, IR, and Raman spectroscopy
but also more specialized techniques such as chemical derivatization, Boehm titrations, EELS, NEXAFS, TPD, and TGA. The chemical
or structural information provided by each technique discussed, as well as their strengths and limitations. Particular emphasis
is placed on XPS and the application of chemical derivatization in conjunction with XPS to quantify functional groups on CNT
surfaces in situations where spectral deconvolution of XPS lineshapes is ambiguous.
相似文献
2.
Application of surface chemical analysis tools for characterization of nanoparticles 总被引:1,自引:1,他引:0
D. R. Baer D. J. Gaspar P. Nachimuthu S. D. Techane D. G. Castner 《Analytical and bioanalytical chemistry》2010,396(3):983-1002
The important role that surface chemical analysis methods can and should play in the characterization of nanoparticles is
described. The types of information that can be obtained from analysis of nanoparticles using Auger electron spectroscopy
(AES), X-ray photoelectron spectroscopy (XPS), time-of-flight secondary-ion mass spectrometry (TOF-SIMS), low-energy ion scattering
(LEIS), and scanning-probe microscopy (SPM), including scanning tunneling microscopy (STM) and atomic force microscopy (AFM),
are briefly summarized. Examples describing the characterization of engineered nanoparticles are provided. Specific analysis
considerations and issues associated with using surface-analysis methods for the characterization of nanoparticles are discussed
and summarized, with the impact that shape instability, environmentally induced changes, deliberate and accidental coating,
etc., have on nanoparticle properties.
相似文献
3.
Bo Yan Zheng-Jiang Zhu Oscar R. Miranda Apiwat Chompoosor Vincent M. Rotello Richard W. Vachet 《Analytical and bioanalytical chemistry》2010,396(3):1025-1035
Monolayer-protected gold nanoparticles (AuNPs) feature unique surface properties that enable numerous applications. Thus,
there is a need for simple, rapid, and accurate methods to confirm the surface structures of these materials. Here, we describe
how laser desorption/ionization mass spectrometry (LDI-MS) can be used to characterize AuNPs with neutral, positively, and
negatively charged surface functional groups. LDI readily desorbs and ionizes the gold-bound ligands to produce both free
thiols and disulfide ions in pure and complex samples. We also find that LDI-MS can provide a semi-quantitative measure of
the ligand composition of mixed-monolayer AuNPs by monitoring mixed disulfide ions that are formed. Overall, the LDI-MS approach
requires very little sample, provides an accurate measure of the surface ligands, and can be used to monitor AuNPs in complex
mixtures.
相似文献
4.
Sen Hou Xinxin Li Xiaoyu Li Xi-Zeng Feng Rui Wang Chen Wang Lei Yu Ming-Qiang Qiao 《Analytical and bioanalytical chemistry》2009,394(3):783-789
Surface wettability conversion with hydrophobins is important for its applications in biodevices. In this work, the application
of a type I hydrophobin HGFI in surface wettability conversion on mica, glass, and poly(dimethylsiloxane) (PDMS) was investigated.
X-ray photoelectron spectroscopy (XPS) and water-contact-angle (WCA) measurements indicated that HGFI modification could efficiently
change the surface wettability. Data also showed that self-assembled HGFI had better stability than type II hydrophobin HFBI.
Protein patterning and the following immunoassay illustrated that surface modification with HGFI should be a feasible strategy
for biosensor device fabrication.
Figure A hydrophobin HGFI has been applied into surface wettability conversion for protein immobilization
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
5.
Hinrichs K Gensch M Esser N Schade U Rappich J Kröning S Portwich M Volkmer R 《Analytical and bioanalytical chemistry》2007,387(5):1823-1829
The standard methods currently used to read out microarrays are fluorescent and chemiluminesent imaging techniques. These
methods require labeling of a component with a marker and, usually, only the concentration of the marker molecule is detected.
A label-free imaging method that also enables quantitative spectroscopic analysis of the composition and component interaction
would be of great advantage. In this article it is shown for the first time that IR mapping ellipsometry enables label-free
imaging of a biochip before and after incubation with peptide solution. The measurements prove that IR ellipsometry is a sensitive
tool for laterally resolved identification of the different materials and determination of the composition of a biochip. The
lateral resolution required was achieved by using radiation from an infrared synchrotron beamline.
相似文献
6.
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.
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7.
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
8.
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
9.
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
10.
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
11.
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
12.
Sen Hou Xin-Xin Li Xiao-Yu Li Xi-Zeng Feng Li Guan Yan-Lian Yang Chen Wang 《Analytical and bioanalytical chemistry》2009,394(8):2111-2117
Controllable cell growth on the defined areas of surfaces is important for potential applications in biosensor fabrication
and tissue engineering. In this study, controllable cell growth was achieved by culturing 293 T fibroblast cells on a mica
surface which had been patterned with collagen strips by a microcontact printing (μCP) technique. The collagen area was designed
to support cell adhesion and the native mica surface was designed to repel cell adhesion. Consequently, the resulting cell
patterns should follow the micro-patterns of the collagen. X-ray photoelectron spectroscopy (XPS), water contact angle (WCA)
measurement, atomic-force microscope (AFM) observation, and force-curve measurement were used to monitor property changes
before and after the collagen adsorption process. Further data showed that the patterned cells were of good viability and
able to perform a gene-transfection experiment in vitro. This technique should be of potential applications in the fields
of biosensor fabrication and tissue engineering.
Figure Controllable cells growth has been achieved by culturing 293T fibroblast cells on the mica surface which had been patterned
with collagen strips by microcontact printing (μCP) technique 相似文献
13.
Roel De Mondt Luc Van Vaeck Andreas Heile Heinrich F. Arlinghaus Frank Vangaever Jens Lenaerts 《Analytical and bioanalytical chemistry》2009,393(8):1917-1921
Recent publications on static secondary ion mass spectrometry (S-SIMS) focus on molecular depth profiling by using polyatomic
or ultra-low energy monoatomic projectiles. Since their applicability depends on the relationship between the ion yield and
the depth, which is hard to obtain without extensive studies, a combination of a wear test method with S-SIMS surface analysis
was performed in the current study. Using this non-sputtering procedure, the relation between the signal intensity and the
local concentration remains in principle the same as that at the surface (which is easy to determine). Mechanical erosion
was successfully applied to expose sub-surface material from organic multilayers. Through surface analysis with S-SIMS on
the gradually exposed deeper planes, molecular depth profiles could be obtained. The study was conducted on a model system
relevant to offset printing, consisting of two polymer layers, containing dyes and a surfactant, cast on an Al substrate.
Figure Concept of mechanical erosion followed by S-SIMS surface analysis to obtain molecular depth profiles 相似文献
14.
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
15.
16.
Fourier transform infrared (FTIR) spectroscopic imaging is a relatively new method that has received great attention as a
new field of analytical chemistry. The greatest benefit of this technique lies in the high molecular sensitivity combined
with a spatial resolution down to a few micrometers. Another advantage is the ability to probe samples under native conditions,
which allows new insights into samples without the need for fixation, stains, or an additional marker. Advances in instrumentation
have made FTIR spectroscopic imaging the tool of choice for an increasing number of applications. The main applications are
in the bioanalytical chemistry of cells and tissue, polymers, and recently as well as in homeland security. This report gives
a short overview of current developments and recent applications.
Figure FTIR image of a polymer blend reveals the chemical composition. Online Abstract Figure (365 KB). 相似文献
17.
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
18.
Zhao Yue Waqas Khalid Marco Zanella Azhar Zahoor Abbasi Andrea Pfreundt Pilar Rivera Gil Kirsten Schubert Fred Lisdat Wolfgang J. Parak 《Analytical and bioanalytical chemistry》2010,396(3):1095-1103
Gold electrodes with switchable conductance are created by coating the gold surface with different colloidal quantum dots.
For the quantum dot immobilization, a dithiol compound was used. By polarizing the electrode and applying a light pointer,
local photocurrents were generated. The performance of this setup was characterized for a variety of different nanoparticle
materials regarding drift and signal-to-noise ratio. We varied the following parameters: quantum dot materials and immobilization
protocol. The results indicate that the performance of the sensor strongly depends on how the quantum dots are bound to the
gold electrode. The best results were obtained by inclusion of an additional polyelectrolyte film, which had been fabricated
using layer-by-layer assembly.
相似文献
19.
20.
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