共查询到20条相似文献,搜索用时 31 毫秒
1.
Chen Z Li G Zhang L Jiang J Li Z Peng Z Deng L 《Analytical and bioanalytical chemistry》2008,392(6):1185-1188
Fluorescence resonance energy transfer (FRET) between a quantum dot as donor and an organic fluorophore as acceptor has been
widely used for detection of nucleic acids and proteins. In this paper, we developed a new method, characterized by 605-nm
quantum dot (605QD) fluorescence intensity increase and corresponding Cy5 fluorescence intensity decrease, to detect adenosine
triphosphate (ATP). The new method involved the use of three different oligonucleotides: 3′-biotin-modified DNA that binds
to streptavidin-conjugated 605QD; 3′-Cy5-labelled DNA; and a capture DNA consisting of an ATP aptamer and a sequence which
could hybridize with both 3′-biotin-modified DNA and 3′-Cy5-labelled DNA. In the absence of the target ATP, the capture DNA
binds to 3′-biotin-modified DNA and 3′-Cy5-labelled DNA, bringing quantum dot and Cy5 into close proximity for greater FRET
efficiency. When ATP is introduced, the release of the 3′-Cy5-labelled DNA from the hybridization complex took place, triggering
605QD fluorescence intensity increase and corresponding Cy5 fluorescence intensity decrease. Taken together, the virtue of
FRET pair 605QD/Cy5 and the property of aptamer-specific conformation change caused by aptamer–ATP interaction, combined with
the fluorescence intensity change of both 605QD and Cy5, provide prerequisites for simple and convenient ATP detection.
Zhang Chen and Guang Li contributed equally to this work. 相似文献
2.
Khalid Hamad Abu-Shandi 《Analytical and bioanalytical chemistry》2009,395(2):527-532
A high-performance liquid chromatographic (HPLC) method with fluorescence detection for the quantification of vancomycin in
human plasma was developed and validated. The method includes an extraction of vancomycin by deproteinization with acetonitrile.
The analyses were carried out at 258 nm as the emission wavelength while exciting at 225 nm on a reversed-phase column (30 cm × 4 mm
i.d. × 10 μm Waters Associates μBondapak C18) using a mobile phase composed of methanol and phosphate buffer at pH 6.3. Vancomycin
was quantitatively recovered from human plasma samples (>96%) with high values of precision. The separation was completed
within 27 min. The calibration curve was linear over the range from 5 to 1,000 ng/mL with the detection and quantification
limits of 2 ng/mL and 5 ng/mL, respectively. This method is suitable for the routine assay of plasma samples.
Figure The effect of the deproteinization solvent on the signal of the interference peak at retention time of 15.0 min. The peak
which interferes with the peaks of Erythromycin and Vancomycin has been disappeared by using 2 mL acetonitrile as the deproteinization
solvent. 相似文献
3.
Michail K Matzi V Maier A Herwig R Greilberger J Juan H Kunert O Wintersteiger R 《Analytical and bioanalytical chemistry》2007,387(8):2801-2814
Hydroxymethylfurfural (HMF), a well-known heterocyclic Maillard reaction product, has often been studied for its potential
toxic, mutagenic, and carcinogenic effects. Recent clinical studies, however, have strongly suggested that HMF might have
exciting antitumor potential. We report on the development and validation of a bioanalytical assay for HMF that could be suitable
as a basis for pharmacokinetic models in cancer patients. Two strategies were tested, i.e., direct and indirect methodologies.
A direct isocratic LC determination at 283 nm was designed. Two indirect attempts involved derivatization coupled to HPLC-UV.
It was possible to resolve the stereoisomers of the HMF derivative, and factors influencing their equilibrium ratio are discussed.
HMF was extracted from the biomatrix by solid-phase extraction using different cartridges. A comparative study was made of
the implemented methods as well as the extraction protocols. Both indirect assays proved to be more sensitive and were used
to assess HMF quantitatively in human plasma. However, the newly introduced derivatization conditions led to the highest sensitivity
with a LOD (S/N ratio = 3) of at least 2 pmol analyte on column. The assay selectivity was satisfactory in pre- and post-dose
real samples. The mean recoveries of the assays were 79% and 89%, with acceptable accuracies and reproducibilities.
Figure Schematic representation of hydroxymethylfurfural (HMF) in human plasma 相似文献
4.
Frank LA Borisova VV Markova SV Malikova NP Stepanyuk GA Vysotski ES 《Analytical and bioanalytical chemistry》2008,391(8):2891-2896
Two kinds of Ca2+-regulated photoprotein obelin with altered color of bioluminescence were obtained by active-center amino acid substitution.
The mutant W92F-H22E emits violet light (λmax = 390 nm) and the mutant Y139F emits greenish light (λ
max = 498 nm), with small spectral overlap, both display high activity and stability and thus may be used as reporters. For demonstration,
the mutants were applied in dual-color simultaneous immunoassay of two gonadotropic hormones—follicle-stimulating hormone
and luteinizing hormone. Bioluminescence of the reporters was simultaneously triggered by single injection of Ca2+ solution, divided using band-pass optical filters and measured with a two-channel photometer. The sensitivity of simultaneous
bioluminescence assay was close to that of a separate radioimmunoassay.
Figure Two kinds of Ca2+-regulated photoprotein obelin with altered color of bioluminescence were obtained and applied in dual-color simultaneous
immunoassay of two gonadotropic hormones. 相似文献
5.
A novel fluorescence quenching method for the determination of cationic surfactants (CS), specifically cetyltrimethylammonium
bromide (CTAB), dodecyltrimethylammonium bromide (DTAB), and cetylpyridinium chloride (CPC), has been developed using water-soluble
luminescent CdTe quantum dots (QDs) modified with thioglycolic acid (TGA). The possible interference from heavy and transition
metals (HTM) has been efficiently eliminated through simple sample treatment with mercapto cotton made in-house. Under optimum
conditions, the extent of fluorescence quenching of CdTe QDs is linearly proportional to the concentration of CS from 2.0 × 10−7 to 7.0 × 10−6 mol L−1 with a detection limit of 5.0 × 10−8 mol L−1. The relative standard deviation for 1.0 × 10−6 mol L−1 CTAB is 2.5% (n = 6). The proposed method exhibits high sensitivity and selectivity and furthermore avoided the use of toxic organic solvents
and tedious solvent extraction procedures. It has been applied to the determination of trace CS in natural river water and
commodity samples with satisfactory results.
Potential interference from heavy and transition metals is eliminated during photoluminescence detection of CS through simple
sample pre-treatment with mercapto cotton 相似文献
6.
Ming-Zhou Zhang Min-Zi Wang Zong-Lun Chen Jie-Hong Fang Mei-Ming Fang Jun Liu Xiao-Ping Yu 《Analytical and bioanalytical chemistry》2009,395(8):2591-2599
A multianalyte lateral-flow immunochromatographic technique using colloidal gold-labeled polyclonal antibodies was developed
for the rapid simultaneous detection of clenbuterol and ractopamine. The assay procedure could be accomplished within 5 min,
and the results of this qualitative one-step assay were evaluated visually according to whether test lines appeared or not.
When applied to the swine urines, the detection limit and the half maximal inhibitory concentration (IC50) of the test strip under an optical density scanner were calculated to be 0.1 ± 0.01 ng mL−1 and 0.1 ± 0.01 ng mL−1, 0.56 ± 0.08 ng mL−1, and 0.71 ± 0.06 ng mL−1, respectively, the cut-off levels with the naked eye of 1 ng mL−1 and 1 ng mL−1 for clenbuterol and ractopamine were observed. Parallel analysis of swine urine samples with clenbuterol and ractopamine
showed comparable results obtained from the multianalyte lateral-flow test strip and GC-MS. Therefore, the described multianalyte
lateral-flow test strip can be used as a reliable, rapid, and cost-effective on-site screening technique for the simultaneous
determination of clenbuterol and ractopamine residues in swine urine.
相似文献
7.
Monterola MP Smith BW Omenetto N Winefordner JD 《Analytical and bioanalytical chemistry》2008,391(7):2617-2626
A simple, fast, reliable, sensitive and potentially portable explosive detection device was developed employing laser photofragmentation
(PF) followed by heterogeneous chemiluminescence (CL) detection. The PF process involves the release of NOx(x = 1,2) moieties from explosive compounds such as TNT, RDX, and PETN through a stepwise excitation–dissociation process using a 193 nm
ArF laser. The NOx(x = 1,2) produced upon PF is subsequently detected by its CL reaction with basic luminol solution. The intensity of the CL signal
was detected by a thermoelectrically cooled photomultiplier tube with high quantum efficiency and negligible dark current
counts. The system was able to detect trace amounts of explosives in various forms in real time under ambient conditions.
Detection limits of 3 ppbv for PETN, 2 ppbv for RDX, and 34 ppbv for TNT were obtained. It was also demonstrated that the
presence of PETN residue within the range of 61 to 186 ng/cm2 can be detected at a given signal-to-background ratio of 10 using a few microjoules of laser energy. The technique also demonstrated
its potential for the direct analysis of trace explosive in soil. An LOD range of 0.5–4.3 ppm for PETN was established, which
is comparable to currently available techniques.
Figure Photofragmentation–chemiluminescence detector 相似文献
8.
Arvand M Pourhabib A Shemshadi R Giahi M 《Analytical and bioanalytical chemistry》2007,387(3):1033-1039
Liquid polymer membrane electrodes based on nickel and manganese phthalocyanines were examined for use as anion-selective
electrodes. The electrodes were prepared by incorporating the ionophores into plasticized poly(vinyl chloride) membranes,
which were directly coated onto the surfaces of graphite electrodes. The resulting electrodes demonstrate near-Nernstian responses
over a wide linear range of perchlorate anion (5 × 10−7 to 1 × 10−1 M). The electrodes have a fast response time, submicromolar detection limits (5 × 10−7 M perchlorate), and could be used over a wide pH range of 3.5–10. The influences of lipophilic cationic and anionic additives
on the response properties of the electrodes were investigated. The proposed sensors revealed high selectivity for perchlorate
over a number of common inorganic and organic anions. The highest selectivity was observed for the electrode based on manganese
phthalocyanine in the presence of the lipophilic anionic additive sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate. Application
of the electrodes to determine perchlorate in tap water and human urine is also reported.
相似文献
9.
The objective of this research was to investigate nanoindentation-induced residual stresses in human enamel using Raman microspectroscopy
and establish if this approach can be used as a stress meter. Healthy human premolars and sintered hydroxyapatite samples
were embedded, cut, and the surfaces were polished finely with a 0.05 μm polishing paste before Berkovich and spherical indentations
were made with a force of 100 mN. Spectra were collected using a Renishaw Raman InVia reflex microscope equipped with an air-cooled
charge-coupled device (CCD) camera. Sample excitation was achieved using either an argon ion laser emitting at 514.5-nm or
a NIR diode laser emitting at 830-nm. The residual micro stresses within and surrounding the indentation impressions were
monitored by mapping the position of the ν1(PO4) band of (crystalline) hydroxyapatite. The Raman maps coincided well with the optical micrographs of the samples. Despite
the presence of a fluorescence background from the organic component of human enamel, spectra collected using 514.5-nm excitation
exhibited more significant shifts in the position of the ν1(PO4) band than spectra collected using 830-nm excitation. This implies that the former excitation may be a more appropriate excitation
for stress detection. It was concluded that Raman microspectroscopy provides a novel high-resolution and non-destructive method
for exploring the role of microstructure on the residual stress distribution within natural biocomposites.
Figure Stress maps of nanoindentation impressions on both human enamel and hydroxyapatite disk via Raman Microspectroscopy 相似文献
10.
Stratis-Cullum DN Griffin GD Mobley J Vo-Dinh T 《Analytical and bioanalytical chemistry》2008,391(5):1655-1660
This paper reports the first intensified biochip system for chemiluminescence detection and the feasibility of using this
system for the analysis of biological warfare agents is demonstrated. An enzyme-linked immunosorbent assay targeting Bacillus globigii spores, a surrogate species for Bacillus anthracis, using a chemiluminescent alkaline phosphatase substrate is combined with a compact intensified biochip detection system.
The enzymatic amplification was found to be an attractive method for detection of low spore concentrations when combined with
the intensified biochip device. This system was capable of detecting approximately 1 × 105
Bacillus globigii spores. Moreover, the chemiluminescence method, combined with the self-contained biochip design, allows for a simple, compact
system that does not require laser excitation and is readily adaptable to field use.
Figure Schematic diagram of the miniature biochip detection system 相似文献
11.
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
12.
Self-assembled monolayers (SAMS) of chemisorbed thioglycollate on a gold electrode surface have been used as a base interface
for the electrostatic adsorption of ferrocenium ion. Electrochemical impedance spectra (EIS) and cyclic voltammetry (CV) were
used to evaluate the electrochemical properties of the supramolecular film. The bare gold electrode failed to distinguish
the oxidation peaks of ascorbic acid (AA) and uric acid (UA) in phosphate buffer solution (PBS, pH 7.0), while the ferricinium–thioglycollate
modified electrode could separate them efficiently. In differiential pulse voltammetric measurements, the prepared gold electrode
could separate AA and UA signals, allowing the simultaneous determination of AA and UA. Under optimal conditions and within
the linear range of 1.0 × 10−6 to 5.0 × 10−4 M, the detection limits of AA and UA achieved were 2.0 × 10−7 and 1.0 × 10−7 M, respectively. The applicability of the prepared electrode was demonstrated by measuring AA and UA in human urine without
any pretreatment.
Figure Fabrication process for the modified electrode 相似文献
13.
We have developed a circular-dichroism thermal lens microscope for UV wavelengths (UV-CD-TLM), for the first time, to realize
sensitive chiral analysis on a microchip. Quasi-continuous-wave phase modulation of a pulsed UV laser was used to generate
left-circularly polarized light and right-circularly polarized light and to detect the generated TL signal amplitude and phase
with a lock-in amplifier. The amplitude and phase were used to determine the concentration and chirality, respectively, of
a sample. The basic principle of UV-CD-TLM for chiral analysis on a microchip was verified by measuring aqueous solutions
of optically active camphorsulfonic acids (CSA). Lower limits of detection (LOD) were calculated at S/N = 2 and were 8.7 × 10−4 mol L−1 (ΔA = 5.2 × 10−6 Abs.) for (+)-CSA and 8.4 × 10−4 mol L−1 (ΔA = 5.0 × 10−6 Abs.) for (−)-CSA. In terms of number of molecules, LODs for UV-CD-TLM were calculated to be 8.7 fmol and 8.4 fmol, respectively.
This is at least three orders of magnitude lower than previously obtained. The applicability of UV-CD-TLM for chiral analysis
on a microchip was verified.
Figure Sensitive chiral analysis by thermal lens microscope (TLM) 相似文献
14.
Highly efficient analysis of underivatized carbohydrates using monolithic-silica-based capillary hydrophilic interaction (HILIC) HPLC 总被引:1,自引:1,他引:0
Ikegami T Horie K Saad N Hosoya K Fiehn O Tanaka N 《Analytical and bioanalytical chemistry》2008,391(7):2533-2542
A polyacrylamide (PAAm)-modified monolithic silica capillary column of increased phase ratio, 200T-PAAm, for hydrophilic interaction
liquid chromatography (HILIC) was prepared. The column showed high separation efficiency, with a theoretical plate height
H = 7–20 μm at a linear velocity, u = 1–7 mm/s. From a kinetic plot analysis, it was expected that the monolithic column could provide three times faster separation
than particle-packed HILIC columns under a pressure limit at 20 MPa. HILIC coupled with electrospray ionization (ESI)–mass
spectrometry (HILIC-ESI-MS) using the 200T-PAAm column was employed for the analysis of underivatized carbohydrates to achieve
fast and efficient separations of mixtures containing mono-, di-, and trisaccharides within 5 min. Under single MS full scan
mode, 200 pg of oligosaccharides was detected by the system. The limit of detection (LOD) of the LC-ESI-MS/MS system was determined
using selected reaction monitoring (SRM) to be as low as 3.2 ng/mL (attomol level) for nonreducing saccharides. The system
was successfully applied to the detection of disaccharides in extracts of plant, such as corn, soybean, and Arabidopsis thaliana.
Figure HILIC-ESI-MS provides a high-efficiency separation and sensitive detection of underivatized carbohydrate oligomers, e.g.,
the homologs of glucose (1) up to maltoheptaose (7) 相似文献
15.
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
16.
Guoqing Wang Chunhong Dong Yukuan Shang Yu-an Sun Dexue Fu Jianbo Zhao 《Analytical and bioanalytical chemistry》2009,394(3):827-833
A method is proposed for monitoring the radix rehmanniae proparate processing procedure and determining the endpoint of the
process using attenuated total reflectance (ATR) FT-IR through nonnegative independent component analysis (ICA). In the proposed
method, ATR FT-IR spectra of the samples were firstly measured at different steaming periods. Then, nonnegative ICA was used
for direct estimation of the feature spectra of the pure components in the mixture without pre-separation and other prior
information. The estimated independent components (ICs) and their variation of the relative concentrations were used to characterize
the processing procedure and determine the endpoint. The results show that the estimated three ICs are consistent with that
of the chemical components in the mixtures, i.e. catalpol/rehmaionoside, glucose, and other compounds that nearly keep invariant
during the processing procedure. The endpoint determined by the IR-ICA method is 15 h, which was located in the range obtained
by expert sensory analysis, whereas the endpoint determined by the traditional sensory analysis is 14 ∼ 17 h and even 14 ∼ 20 h,
which showed the significant deviation of the endpoints determined by different operators.
Figure Characterisation of radix rehmanniae processing procedure using FT-IR spectroscopy through nonnegative independent component
analysis 相似文献
17.
R. DellAnna P. Lazzeri M. Frisanco F. Monti F. Malvezzi Campeggi E. Gottardini M. Bersani 《Analytical and bioanalytical chemistry》2009,394(5):1443-1452
The discrimination and classification of allergy-relevant pollen was studied for the first time by mid-infrared Fourier transform
infrared (FT-IR) microspectroscopy together with unsupervised and supervised multivariate statistical methods. Pollen samples
of 11 different taxa were collected, whose outdoor air concentration during the flowering time is typically measured by aerobiological
monitoring networks. Unsupervised hierarchical cluster analysis provided valuable information about the reproducibility of
FT-IR spectra of the same taxon acquired either from one pollen grain in a 25 × 25 μm2 area or from a group of grains inside a 100 × 100 μm2 area. As regards the supervised learning method, best results were achieved using a K nearest neighbors classifier and the leave-one-out cross-validation procedure on the dataset composed of single pollen grain
spectra (overall accuracy 84%). FT-IR microspectroscopy is therefore a reliable method for discrimination and classification
of allergenic pollen. The limits of its practical application to the monitoring performed in the aerobiological stations were
also discussed.
Figure Traditional and innovative methods for the identification of airborne pollen grains 相似文献
18.
Lee KC Cheuk MW Chan W Lee AW Zhao ZZ Jiang ZH Cai Z 《Analytical and bioanalytical chemistry》2006,386(7-8):2225-2232
A reversed-phase HPLC method has been developed for determination of twelve intact glucosinolates—glucoiberin, glucocheirolin,
progoitrin, sinigrin, epiprogoitrin, glucoraphenin, sinalbin, gluconapin, glucosibarin, glucotropaeolin, glucoerucin, and
gluconasturtiin—in ten traditional Chinese plants. The samples were extracted with methanol and the extracts were cleaned
on an activated Florisil column. A mobile phase gradient prepared from methanol and 30 mmol L−1 ammonium acetate at pH 5.0 enabled baseline separation of the glucosinolates. Glucosinolate detection was confirmed by quadrupole
time-of-flight tandem mass spectrometric analysis in negative-ionization mode. Detection limits ranged from 0.06 to 0.36 μg
g−1 when 5 g of dried plant was analyzed. Recoveries of the glucosinolates were better than 85% and precision (relative standard
derivation, n = 3) ranged from 5.3 to 14.6%. Analysis of the glucosinolates provided scientific evidence enabling differentiation of three
pairs of easily confused plants.
Figure Glucosinolates Analysis for the Differentiation of Easily-Confusing Herbs 相似文献
19.
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
20.
Antje Vollmer Kristin Voiges Christian Bork Kathrin Fiege Katja Cuber Petra Mischnick 《Analytical and bioanalytical chemistry》2009,395(6):1749-1768
Dextrans from Leuconostoc ssp., α-1,6-linked glucans branched at O-3, were O-methylated in DMSO with lithium dimsyl and methyl iodide under various conditions. Methyl substituent distribution was comprehensively
studied in the terminal, internal, and branched glucosyl units and along and over the dextran macromolecules. The order of
reactivity was O-2 > O-4 ≥ O-3. The methyl pattern in the glucosyl units significantly deviates from a random distribution
with enhanced amounts of un- and trisubstituted moieties. This deviation was found to proceed on macromolecular level by means
of ESI-MS of perdeuteromethylated and partially depolymerized methyl dextrans. Heterogeneity was much more pronounced than
for methyl amylose prepared under comparable conditions. DS gradients in and over the material are discussed with respect
to dextran structure and the mechanism of Li dimsyl alkylation. For comparison, cyanoethyl dextrans were prepared by sodium
hydroxide catalyzed addition of acrylonitrile. Monomer analysis of cyanoethyl dextrans revealed that this thermodynamically
controlled reaction gave a random substitution pattern with 48% of cyanoethyl groups at O-2, 33% at O-4, and 19% at O-3.
相似文献