共查询到20条相似文献,搜索用时 31 毫秒
1.
J. L. López-Paz M. Catalá-Icardo B. Antón-Garrido 《Analytical and bioanalytical chemistry》2009,394(4):1073-1079
A simple, economic, sensitive and rapid method for the determination of the pesticide diquat was described. This new method
was based on the coupling of flow injection analysis methodology and direct chemiluminescent detection; to the authors’ knowledge,
this approach had not been used up to now with this pesticide. It was based on its oxidation with ferricyanide in alkaline
medium; significant improvements in the analytical signal were achieved by using high temperatures and quinine as sensitiser.
Its high throughput (144 h−1), together with its low limit of detection (2 ng mL−1), achieved without need of preconcentration steps, permitted the reliable quantification of diquat over the linear range
of (0.01–0.6) μg mL−1 in samples from different origins (river, tap, mineral and ground waters), even in the presence of a 40-fold concentration
of paraquat, a pesticide commonly present in the commercial formulations of diquat.
Figure Quartz luminometer cell 相似文献
2.
Eric B. Kalman Olivier Sudre Ivan Vlassiouk Zuzanna S. Siwy 《Analytical and bioanalytical chemistry》2009,394(2):413-419
Control of ionic transport through nanoporous systems is a topic of scientific interest for the ability to create new devices
that are applicable for ions and molecules in water solutions. We show the preparation of an ionic transistor based on single
conical nanopores in polymer films with an insulated gold thin film “gate.” By changing the electric potential applied to
the “gate,” the current through the device can be changed from the rectifying behavior of a typical conical nanopore to the
almost linear behavior seen in cylindrical nanopores. The mechanism for this change in transport behavior is thought to be
the enhancement of concentration polarization induced by the gate.
Figure
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
3.
van Zomeren A van der Weij-Zuiver E Comans RN 《Analytical and bioanalytical chemistry》2008,391(6):2365-2370
Characterization of humic substances (HS) in environmental samples generally involves labor-intensive and time-consuming isolation
and purification procedures. In this paper, the development of an automated system for HS isolation and purification is described.
The novelty of the developed system lies in the way the multiple liquids and columns used in the isolation/purification procedure
are handled in both forward and back-elution mode by solenoid valves. The automated procedure significantly reduces the total
throughput time needed, from 6–7 days to 48 h, and the amount of labor to obtain purified HS for further characterization.
Chemical characterization of purified HS showed that results were in good agreement with previously published values for HS
from a variety of sources, including the IHSS standard HS collection. It was also shown that the general properties of HS
were consistent among the different source materials (soil, waste, aquatic) used in this study. The developed system greatly
facilitates isolation and characterization of HS and reduces the risk of potential (time-dependent) alteration of HS properties
in the manual procedure.
Figure Photograph of the rear (left) and front (right) of the automated system for the isolation and purification of humic substances
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
4.
Aguinaga N Campillo N Viñas P Hernández-Córdoba M 《Analytical and bioanalytical chemistry》2008,391(3):753-758
A sensitive and solvent-free method for the determination of ten polycyclic aromatic hydrocarbons, namely, naphthalene, acenaphthylene,
acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo[a]anthracene and chrysene, with up to four aromatic rings, in milk samples using headspace solid-phase microextraction and
gas chromatography–mass spectrometry detection has been developed. A polydimethylsiloxane–divinylbenzene fiber was chosen
and used at 75°C for 60 min. Detection limits ranging from 0.2 to 5 ng L−1 were attained at a signal-to-noise ratio of 3, depending on the compound and the milk sample under analysis. The proposed
method was applied to ten different milk samples and the presence of six of the analytes studied in a skimmed milk with vegetal
fiber sample was confirmed. The reliability of the procedure was verified by analyzing two different certified reference materials
and by recovery studies.
Figure Milk is safe, healthy food 相似文献
5.
Jung C 《Analytical and bioanalytical chemistry》2008,392(6):1031-1058
Cytochrome P450 proteins (CYPs) are a big class of heme proteins which are involved in various metabolic processes of living
organisms. CYPs are the terminal catalytically active components of monooxygenase systems where the substrate binds and is
hydroxylated. In order to be functionally competent, the protein structures of CYPs possess specific properties that must
be explored in order to understand structure–function relationships and mechanistic aspects. Fourier transform infrared spectroscopy
(FTIR) is one tool that is used to study these structural properties. The application of FTIR spectroscopy to the secondary
structures of CYP proteins, protein unfolding, protein–protein interactions and the structure and dynamics of the CYP heme
pocket is reviewed. A comparison with other thiolate heme proteins (nitric oxide synthase and chloroperoxidase) is also included.
Figure The protein secondary structure, protein unfolding, redox-partner protein–protein interaction, structural changes induced
by the reduction of the heme iron, and the structure and dynamics of the active site of cytochromes P450 (CYP) can be studied
using Fourier transform infrared spectroscopy (FTIR). FTIR spectroscopy is a good approach for gaining a deeper insight into
structure–function relationships in CYPs.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 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.
Aguinaga N Campillo N Viñas P Hernández-Córdoba M 《Analytical and bioanalytical chemistry》2008,391(4):1419-1424
This paper describes a headspace solid-phase microextraction (HS-SPME) procedure coupled to gas chromatography with mass spectrometric
detection (GC–MS) for the determination of eight PAHs in aquatic species. The influence of various parameters on the PAH extraction
efficiency was carefully examined. At 75 °C and for an extraction time of 60 min, a polydimethylsiloxane–divinylbenzene (PDMS/DVB)
fiber coating was found to be most suitable. Under the optimized conditions, detection limits ranged from 8 to 450 pg g−1, depending on the compound and the sample matrix. The repeatability varied between 7 and 15% (RSD). Accuracy was tested using
the NIST SRM 1974b reference material. The method was successfully applied to different samples, and the studied PAHs were
detected in several of the samples.
Figure Headspace SPME sampling followed by GC–MS facilitates routine monitoring of PAHs in aquatic species 相似文献
8.
Pérez-Sirvent C Martínez-Sánchez MJ García-Lorenzo M López-García I Hernández-Córdoba M 《Analytical and bioanalytical chemistry》2007,388(2):495-498
Use of small membrane pumps, instead of peristaltic pumps, to introduce sample and reagent solutions into the spectrometer
has several advantages in atomic fluorescence spectrometric determination of mercury. This simple modification results in
a substantial saving in the time required for the measurements and so 90% of reagent solution volumes and 95% of sample solution
volumes are saved, with a consequent decrease in the volume of waste generated. The sampling frequency is almost tripled,
with no deterioration in sensitivity, which is similar to that obtained by use of peristaltic pumps. The relative standard
deviation for ten consecutive measurements of a 1 μg L−1 mercury solution was approximately 2%.
Figure Small membrane pumps for the atomic fluorescene spectro metric determination of mercury 相似文献
9.
An ordinary atomic force microscopy (AFM) was functionalized and applied to electrochemically draw micropatterns of biomolecules.
To fabricate an electrochemical AFM probe having an electrode at the tip, a metal-coated AFM probe was first insulated with
Parylene C, and then the apex of the tip was ground mechanically to expose the electrode. The effective electrode diameter
was estimated to be ca. 500 nm. The electrode probe was positioned close to a heparin-coated antibiofouling substrate and
used to locally generate hypobromous acid from a dilute Br− solution to render the substrate surface protein-adhesive. In situ topographical imaging after the electrochemical treatment
suggested the heparin layer became detached to allow the adsorption of proteins, in this case fibronectin. The diameter of
the drawn fibronectin pattern was 2 μm, which is one order of magnitude smaller than we achieved previously using a microdisk
electrode (tip diameter 10 μm).
Figure AFM configuration integrated with the electrochemical-based surface modification and resultant micropatterns of fluorescence-labeled
fibronectin
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
10.
An intercomparison to establish the performance of routine laboratories in the determination of polybrominated flame retardants
in polymers was organised. Commercial poly(ethyleneterephthalate) was fortified with technical pentabromodiphenyl ether, octabromodiphenyl
ether and decabromodiphenyl ether mixtures and with a decabromobiphenyl technical mixture at 0.4–0.8 g/kg. Homogeneity and
stability of the total Br content in the material was confirmed. Thirty-seven laboratories from Europe, Asia and the Americas
submitted results. Relative repeatability standard deviations for individual congeners ranged from 7 to 17%. Relative between-laboratory
standard deviations ranged from 22 to 61%. No significant influence of a common standard, application of a standard method
or method parameters could be identified. The quality and uncertainty of the results of this study are significantly worse
than those reported in the environmental field and indicate a clear need for a learning process among the laboratories involved.
Figure Mandel’s h (between labs): critical level: 1.91 相似文献
11.
A screen-printed (SP) microarray is presented as a platform for the achievement of multiparametric biochips. The SP platform
is composed of eight (0.28-mm2) working electrodes modified with electroaddressed protein A-aryl diazonium adducts. The electrode surfaces are then used
as an affinity immobilisation support for the orientated binding of capture monoclonal antibodies, having specificity against
four different point-of-care related proteins (myoglobin, cardiac troponin I, C-reactive protein and brain natriuretic peptide).
The immobilised capture antibodies are involved in sandwich assays of the four proteins together with biotinylated detection
antibodies and peroxidase-labelled streptavidin in order to permit a chemiluminescent imaging of the SP platform and a sensitive
detection of the assayed proteins. The performances of the system in pure buffered solutions, using a 25-min assay duration,
were characterised by dynamic ranges of 0.5–50, 0.1–120, 0.2–20 and 0.67–67 μg/L for C-reactive protein, myoglobin, cardiac
troponin I and brain natriuretic peptide, respectively. The four different assays were also validated in spiked 40-times-diluted
human sera, using LowCross buffer, and were shown to work simultaneously in this complex medium.
Figure Principle of the screen-printed POC microarray and a schematic representation of the assay architecture.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
12.
Competitive adsorption on adsorptive solid-phase microextraction (SPME) fibres implies careful determination of operating
conditions for reliable quantitative analysis of VOCs in indoor air. With this objective, two analytical approaches, involving
non-equilibrium and equilibrium extraction, were compared. The average detection limit obtained for GC-MS analysis of nine
VOCs by the equilibrium method is 0.2 μg m−3, compared with 1.9 μg m−3 with the non-equilibrium method. The effect of the relative humidity of the air on the calibration plots was studied, and
shown to affect acetone adsorption only. Hence, the concentrations that can be accurately determined are up to 9 μmol m−3. The methods were then applied to indoor air containing different concentrations of VOCs. The non-equilibrium method, involving
short extraction time, can be used for detection of pollution peaks whereas equilibrium extraction is preferable for measurement
of sub-μg m−3 ground concentration levels.
相似文献
13.
The enantioresolution of zolmitriptan was performed using cyclodextrin (CD)-modified capillary zone electrophoresis (CZE)
with hydroxypropyl-β-CD (HP-β-CD) as the chiral selector. The influence of experimental conditions on the enantioseparation
of zolmitriptan, such as pH, temperature, applied voltage, and concentrations of running electrolyte and CD, was systematically
investigated, obtaining a baseline separation of two enantiomers by the use of a 25 mM sodium dihydrogen phosphate (SDPH)
running electrolyte (pH 2.4) containing 30 mM HP-β-CD at 15 °C. Binding constants for each enantiomer–HP-β-CD pair at different
temperatures, as well as thermodynamic parameters for binding, were calculated. A nonlinear van’t Hoff plot was obtained,
indicating that the thermodynamic parameters of complexation were temperature-dependent for zolmitriptan enantiomers. The
significant contribution of the enthalpy difference to the Gibbs free energy change suggested a stereomeric barrier mechanism
for chiral recognition.
Figure Resolution of zolmitriptan enantiomers was achieved by using CD-modified CZE
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
14.
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
15.
Enhanced recognition of non-complementary hybridization by single-LNA-modified oligonucleotide probes 总被引:1,自引:0,他引:1
XianYu Piao Ying Yan Jing Yan YiFu Guan 《Analytical and bioanalytical chemistry》2009,394(6):1637-1643
Locked nucleic acid (LNA) is a deoxyribonucleotide analogue with an unusual ‘locked’ furanose conformation. LNA-modified oligonucleotide
probes have demonstrated an enhanced binding affinity towards their complementary strands; however, their potential to discriminate
non-complementary hybridization of mismatches has not been explored. In this study, we investigated the effect of the chemical
nature of LNA nucleobases on the hybridization stability and the capability of LNA-modified oligonucleotides to discriminate
the LNA:DNA mismatched base pairs. It was observed that LNA modification indeed improves the discrimination capability of
oligonucleotides by increasing the melting temperature differences between the complementary duplexes and hybrids containing
mismatches. Particularly, LNA purines offer a greater potential to recognize the mismatches than LNA pyrimidines and DNA purines.
Real-time PCR experiments further confirmed that LNA modifications at the 3′-end are more effective. The results and conclusions
in this study provide useful information for hybridization-based nucleic acid analysis where designing sound oligonucleotide
probes is crucial to the success of the analyses.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
16.
Phillips KM Wolf WR Patterson KY Sharpless KE Holden JM 《Analytical and bioanalytical chemistry》2007,389(1):219-229
Over a 6.5-year period a total of 2554 values were reported by nine laboratories for 259 certified or reference nutrient concentrations
in 26 certified reference materials (CRM) submitted to contract laboratories, blinded, as part of the qualifying process for
analytical contracts and in the routine sample stream as part of the National Food and Nutrient Analysis Program. Each value
was converted to a Z′-score, reflecting the difference from the assigned value related to the combined expected analytical uncertainty plus the
uncertainty in the CRM value. Z′-scores >|3.0| were considered unacceptable. For some nutrients (Na, folate, dietary fiber, pantothenic acid, thiamin, tocopherols,
carotenoids, monounsaturated, and polyunsaturated fatty acids), >20% of Z′-scores were >|3.0|. For total fat, vitamin C, and niacin >25% of Z′-scores were >|2.0|. Components for which CRM data were
best (more than 90% of Z′-scores <|2.0|) were Mg, P, Mn, Se, and vitamin B12. In some cases deviations from assigned values were not uniform across
laboratories and materials. For Na almost all high Z′-scores were for low-Na matrices, suggesting analytical problems related to concentration.
Figure Z′-scores for vitamins in certified reference materials
Disclaimer: Certain commercial equipment, instruments, or materials are identified in this paper in order to specify the experimental
procedure adequately. Such identification is not intended to imply recommendation or endorsement by the National Institute
of Standards and Technology, or the United States Department of Agriculture, nor is it intended to imply that the materials
or equipment identified are necessarily the best available for the purpose. 相似文献
17.
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
18.
Destandau E Lefèvre JP Chouai Fakhr Eddine A Desportes S Jullien MC Hierle R Leray I Valeur B Delaire JA 《Analytical and bioanalytical chemistry》2007,387(8):2627-2632
A microfabricated device has been developed for fluorimetric detection of potassium ions without previous separation. It is
based on use of a fluorescent molecular sensor, calix–bodipy, specially designed to be sensitive to and selective for the
target ion. The device is essentially made of a Y-shape microchannel moulded in PDMS fixed on a glass substrate. A passive
mixer is used for mixing the reactant and the analyte. The optical detection arrangement uses two optical fibres, one for
excitation by a light-emitting diode, the other for collection of the fluorescence. This system enabled the flow-injection
analysis of the concentration of potassium ions in aqueous solutions with a detection limit of 0.5 mmol L−1 and without interference with sodium ions. A calibration plot was constructed using potassium standard solutions in the range
0–16 mmol L−1, and was used for the determination of the potassium content of a pharmaceutical pill.
Figure Photography of the microfluidic channel showing the ridges in the PDMS substrate at the top of the channel 相似文献
19.
Gross JH Nieth N Linden HB Blumbach U Richter FJ Tauchert ME Tompers R Hofmann P 《Analytical and bioanalytical chemistry》2006,386(1):52-58
Liquid injection field desorption/ionization (LIFDI) has been applied to identify transition metal complexes that are highly
reactive to air and moisture by mass spectrometry. The complexes of nickel and rhodium were supplied as dilute solutions (∼0.2 mg
ml−1) in toluene, tetrahydrofuran or acetonitrile, and were applied onto the field desorption emitter inside the vacuum of the
ion source under inert conditions by means of the injection capillary unique to the LIFDI set-up. LIFDI mass spectrometry
on a double-focusing magnetic sector instrument provided spectra exhibiting intense molecular ion peaks for the species investigated
or signals that could easily be related to the target compound by assuming neutral loss of the weakest-bound ligand. Eventually,
byproducts of the synthesis or other components resulting from incomplete reactions or some degree of decomposition were also
detected.
Dedicated to Prof. J. J. Veith on the occasion of his 65th birthday. 相似文献
20.
Development of a chemiluminescent ELISA and a colloidal gold-based LFIA for TNT detection 总被引:1,自引:0,他引:1
S. Girotti S. Eremin A. Montoya M. J. Moreno P. Caputo M. D’Elia L. Ripani F. S. Romolo E. Maiolini 《Analytical and bioanalytical chemistry》2010,396(2):687-695
To identify the explosive used in a terrorist attack, or to obtain an early sign of environmental pollution it is important
to use simple and rapid assays able to detect analytes at low levels, possibly on-site. This is particularly true for TNT
(2,4,6-trinitrotoluene), one of the most employed explosives in the 20th century and at the same time, because of its toxicity,
a well known pollutant. In this work we describe the development of an indirect competitive ELISA with chemiluminescent detection
(CL-ELISA) and of a lateral-flow immunoassay (LFIA) based on colloidal gold nanoparticle labels. A commercially available
monoclonal antibody was used and 13 specially synthesized conjugates were tested. We optimized the assay by determining the
optimal concentration of monoclonal antibody and conjugates and the influence of various non-specific factors such as: tolerance
to organic solvents at different concentrations, the washing and competitive step time, and the cross-reactivity with related
compounds. The sensitivity and reproducibility of the CL-ELISA were good (LOD and IC50 values in the ng mL−1 range, and CV value about 7%). It has been applied to real samples of various materials involved in a controlled explosion
of an “improvised explosive device”. Three extraction procedures were tested on these samples, all employing methanol as the
solvent. The lateral flow immunoassay (LFIA), developed by using the same immunoreagents, reached a detection limit of 1 μg mL−1 when tested on the same samples analysed by CL-ELISA.
相似文献