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1.
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
2.
A novel headspace solid-phase microextraction method for the exact determination of organochlorine pesticides in environmental soil samples 总被引:2,自引:0,他引:2
Zhao R Wang X Yuan J Jiang T Fu S Xu X 《Analytical and bioanalytical chemistry》2006,384(7-8):1584-1589
A novel method of determining organochlorine pesticides (OCPs) is described. It is based on solid-phase microextraction (SPME) and gas chromatography–electron capture detection. During the development of the method, soil samples were prepared, spiked with standard solution, and then aged for some time. Extraction conditions such as the extraction time, the NaCl content, the volume of water, the extraction temperature and the desorption time were investigated and optimized. The limits of detection obtained using the method ranged from 0.10 to 0.51 ng g−1, and relative standard deviations were lower than 10% for most organochlorine pesticides. Real soil samples were successfully analyzed using the proposed method. The results from the method developed here were in good agreement with those obtained using ultrasonic extraction. The result demonstrates that aging soils spiked with standard solution is an important method development step, because the soil samples obtained using this approach are more like real soils than those obtained when aging is not used.
相似文献
3.
A method is described for determination of residues of the insecticide Etofenprox in environmental samples. Anionic surfactant
micelle-mediated extraction (coacervation extraction) was evaluated for isolation of Etofenprox before HPLC. The optimum conditions
used for extraction included: 0.09 g sodium dodecanesulfonate (SDoS), 3.1 mL (3.3, for concentrations below 0.04 mg L−1) 12 mol L−1 HCl, 5 min vortex stirring, 5 min centrifugation at 4000 rpm, 2 h equilibration time. The limits of quantification (LOQ)
and detection (LOD) were 0.01 and 0.004 mg L−1, respectively, and recoveries obtained from five real samples ranged from 94.33±2.48 to 100.13±2.71%. The precision of the
method was good; relative standard deviations (RSD) were less than 7%.
相似文献
4.
Ortner K Sivanandam VN Buchberger W Müller N 《Analytical and bioanalytical chemistry》2007,388(1):173-177
Enzymatically cleaved glycans from sub-milligram quantities of erythropoietin (EPO) and ovalbumin have been analyzed, without
further purification, by two-dimensional diffusion-ordered nuclear magnetic resonance spectroscopy. At NMR sample concentrations
below 50 μmol L−1 the major components of the oligosaccharide fractions could be distinguished by their anomeric proton chemical shift and
their size-dependent diffusion coefficients.
Figure
1H NMR diffusion decay curves of anomeric protons in the EPO glycan fraction 相似文献
5.
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
6.
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.
相似文献
7.
Lee JO So HM Jeon EK Chang H Won K Kim YH 《Analytical and bioanalytical chemistry》2008,390(4):1023-1032
Recent advances in nanotechnology have enabled the development of nanoscale sensors that outperform conventional biosensors.
This review summarizes the nanoscale biosensors that use aptamers as molecular recognition elements. The advantages of aptamers
over antibodies as sensors are highlighted. These advantages are especially apparent with electrical sensors such as electrochemical
sensors or those using field-effect transistors.
Figure Feeling proteins with aptamer-functionalized carbon nanotubes 相似文献
8.
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
9.
Chen F Chen L Wang Q Zhou J Xue X Zhao J 《Analytical and bioanalytical chemistry》2009,393(3):1073-1079
A rapid and reliable method was developed and applied for the simultaneous determination of 17 organochlorine pesticides (OCPs)
in propolis. After extraction with hexane and acetone (1:1, v/v), four sorbents (florisil, silica, graphitized carbon, and
tandem graphitized carbon plus florisil) were assayed for the clean-up step. The elution solvents hexane and ethyl acetate
(1:1, v/v), hexane and dichloromethane (3:7, v/v), and ethyl acetate and hexane (2:8, v/v) were studied. The results showed
that the combination of the tandem graphitized carbon and florisil cartridge with the elution solvent of 6mL of ethyl acetate
and hexane (2:8, v/v), which was capable of eliminating matrix interference and providing colorless eluates, was the most
efficient clean-up procedure for propolis extracts when testing for OCPs. The analytical technique employed was gas chromatography
with electron capture detection (GC–ECD). The correlation coefficients from linear regression for the analyzed concentrations
(5∼100 μg/kg) were >0.9961. The limits of detection (LODs) varied between 0.8 μg/kg for 4,4′-DDE and 11.4 μg/kg for endosulfan
II, and the limits of quantitation (LOQs) ranged from 2.6 to 38.1 μg/kg. The average recoveries varied between 62.6 and 109.6%.
Relative standard deviations (RSD%) ranged from 0.8 to 9.4%. Sample analysis indicated that 4,4′-DDE was detected more often
in propolis than other pesticides, such as β-HCH, δ-HCH and heptachlor.
Figure GC-ECD chromatogram of a standard solution with 0.1 mg/L of OCPs 相似文献
10.
Martínez Ocaña R Mena Granero A Egea Gonzalez FJ Garrido Frenich A Martínez Vidal JL Plaza Bolaños P 《Analytical and bioanalytical chemistry》2008,390(5):1413-1423
A multiresidue method for determining 22 polychlorinated biphenyls (PCBs) in air has been developed and validated by gas chromatography
(GC) coupled to tandem mass spectrometry (MS/MS) using a triple quadrupole analyzer (QqQ). The method was validated in terms
of both steps of sampling and analysis. The sampling method, which is based on active sampling using polyurethane foam (PUF)
as adsorbent, was validated by generating standard atmospheres. The retention capacity of this sampling sorbent allows up
to 5 m3 of air to be sampled without any breakthrough for most compounds. Two solvent extraction methods were compared: sonication
and Soxhlet extraction with a mixture of n-hexane:diethyl ether (95:5 v/v). Both extraction methods yielded similar results, but the first one required less solvent
and time. The method exhibited good accuracy (80.3–99.8%), precision (2.2–15.2%) and lower limits that allowed quantification
and confirmation at levels as low as 0.008 ng/m3. Finally, the method was applied to the analysis of PCBs in the air in areas near to a municipal solid-waste landfill and
directly above the refuse in the landfill, where it indicatedd the presence of some of the target compounds.
Figure General chemical structure of polychlorinated biphenyls 相似文献
11.
12.
An X-ray fluorescence method (XRF) is presented that allowed low detection limits (at the 0.1–23 ng mL−1 level) to be obtained for Cr, Mn, Fe, Ni, Zn, Sr, Pb, Bi and Br in water. The samples were prepared using a thin layer method. Trace elements were determined via the calibration curve and standard addition. Absorption effects and inhomogenities in prepared samples were checked for using the emission–transmission method and internal standards, respectively. The results from the XRF method were compared with the results from the inductively coupled plasma atomic emission spectrometry method.
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13.
Goryacheva IY Basova EY Van Peteghem C Eremin SA Pussemier L Motte JC De Saeger S 《Analytical and bioanalytical chemistry》2008,390(2):723-727
A rapid easy-to-use immunoassay was optimised for the non-instrumental detection of ochratoxin A (OTA) in beer. The analytical
method involves preconcentration on the immunoaffinity layer inside a column followed by direct competitive ELISA detection
in the same layer. The visual cut-off value, i.e. the lowest OTA concentration resulting in no colour development, was 0.2 μg
L-1. Assay validation was performed using samples spiked with OTA. Thirty-seven naturally contaminated samples were screened
with the gel-based method developed and no false-negative results were obtained. The method described offers a simple, rapid
and cost-effective screening tool, thus contributing to better health protection of consumers.
Figure Gel-based immunoassay of spiked beer samples. 相似文献
14.
Cordes DB Miller A Gamsey S Singaram B 《Analytical and bioanalytical chemistry》2007,387(8):2767-2773
The simultaneous use of several fluorescent reporter dyes in a multicomponent boronic acid-based glucose sensing system is
reported. In one application, two dyes with widely different emission wavelengths are used to report changes in glucose concentration.
A third glucose-insensitive dye was then added to act as a reference dye and provide for a ratiometric correction to the two
reporter dye signals. The inclusion of such a reference dye reduces errors arising from sources such as fluctuations in lamp
intensity and sample dilution.
The simultaneous use of multiple fluorescent reporter dyes 相似文献
15.
This paper describes a liquid chromatographic/tandem mass spectrometric (LC/MS–MS) method specifically designed for the screening
of synthetic glucocorticosteroids in human urine. The method is designed to recognize a common mass spectral fragment formed
from the particular portion of the molecular structure that is common to all synthetic glucocorticosteroids and that is fundamental
to their pharmacological activity. As such, the method is also suitable for detecting unknown substances, provided they contain
the portion of the molecular structure selected as the analytical target. The effectiveness of this approach was evaluated
on seventeen synthetic glucocorticosteroids. Urine samples, including blank urines spiked with one or more synthetic glucocorticosteroids,
were treated according to a standard procedure (enzymatic hydrolysis, liquid/liquid extraction and evaporation to dryness)
and analyzed using LC/MS-MS with electrospray ionization (ESI). MS–MS acquisition was carried out in a precursor ion scan,
and the results were compared with those obtained by a previously developed reference technique based on acquisition in the
multiple reaction monitoring (MRM) mode. All of the glucocorticosteroids considered in this study are clearly detectable in
urine, with a limit of detection in the concentration range 5–20 ng/mL, depending on the glucocorticosteroid structure. The
proposed method is therefore suitable for the detection of glucocorticosteroids in urine samples taken for “in competition”
sport anti-doping control tests, matching the requirements of the World Anti-Doping Agency (WADA) for accredited anti-doping
laboratories.
Figure Structures of the synthetic glucocorticoids considered in this study 相似文献
16.
17.
We quantitatively modeled the volume phase transition of a hydrogel containing a crystalline colloidal array with a crown
ether ligand which binds Pb2+. The hydrogel volume response and the wavelength diffracted depend on the Pb2+ concentration and on both the ionic strength and the valence of the nonbinding ionic species. We successfully modeled the
response of this hydrogel Pb2+ sensor to ionic strength and the cation valence of the added salts.
Figure Cation identity dependence of crown ether photonic crystal Pb+ sensing 相似文献
18.
Templating is an effective way for the structural modifications of a material and hence for altering its functional properties.
Here protein imprinting was exploited to alter polymeric polyacrylamide (PAA) membranes. The sieving properties and selection
abilities of the material formed were evaluated by studying the electrically driven transport of various proteins across templated
PAA membranes. The sieving properties correlated with the templating process and depended on the quantity of template used
during the polymerisation. For 1 mg/mL protein-templated membranes a ‘gate effect’ was shown, which induced a preferential
migration of the template and of similar-size proteins. Such template preferential electrotransport was exploited for the
selective removal of certain proteins in biological fluids prior to proteome analysis (depletion of albumin from human serum);
the efficiency of the removal was demonstrated by analysing the serum proteome by two-dimensional electrophoresis experiments.
Figure PAA templeted membrane for the electroremoval of serum albumin before proteome analysis 相似文献
19.
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
20.
Ma X Zhu T Xu H Li G Zheng J Liu A Zhang J Du H 《Analytical and bioanalytical chemistry》2008,390(4):1133-1137
A chemical prototype sensor was constructed based on nanofiber-structured TiO2 and highly sensitive quartz resonators. The gas-sensing behavior of this new sensor to selected simulant warfare agents was
investigated at room temperature. Results showed rapid response and good reversibility of this sensor when used with high-purity
nitrogen. This provides a simple approach to preparation of materials needed as chemical sensors for selected organic volatiles
or warfare agents.
Figure Sensing behavior of TiO2 nanofiber sensor to chemical vapors 相似文献