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1.
Screening and analysis of an antineoplastic compound in Rhizoma Chuanxiong by means of in vitro metabolism and HPLC-MS 总被引:1,自引:0,他引:1
A new screening and analysis method that combines in vitro metabolism with high-performance liquid chromatography-mass spectrometry
(HPLC-MS) was developed for the screening and analysis of an antineoplastic compound, coniferyl ferulate, which is present
in the rhizome of Rhizoma Chuanxiong. Infrared (IR), ultraviolet visible spectroscopy (UV-Vis), nuclear magnetic resonance (NMR) and element analysis were used
to identify the molecular structure of coniferyl ferulate. The quantitative analysis of coniferyl ferulate in different extracts
of Rhizoma Chuanxiong was carried out, and the metabolism of coniferyl ferulate was investigated by in vitro incubation with rat liver homogenate.
The metabolite of coniferyl ferulate, ferulic acid ethyl ester, was identified by HPLC-MS, UV-Vis and IR. In addition, antineoplastic
activities of coniferyl ferulate and ferulic acid ethyl ester were detected by the MTT assay. The observed inhibition rate
of coniferyl ferulate on the activity of HeLa cells was over 80% at 5.4 ng μl−1. However, its metabolite, ferulic acid ethyl ester, showed no antineoplastic activity in vitro.
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2.
Schütz K Persike M Carle R Schieber A 《Analytical and bioanalytical chemistry》2006,384(7-8):1511-1517
The anthocyanin pattern of artichoke heads (Cynara scolymus L.) has been investigated by high-performance liquid chromatography–electrospray ionization mass spectrometry. For this purpose a suitable extraction and liquid chromatographic method was developed. Besides the main anthocyanins—cyanidin 3,5-diglucoside, cyanidin 3-glucoside, cyanidin 3,5-malonyldiglucoside, cyanidin 3-(3′′-malonyl)glucoside, and cyanidin 3-(6′′-malonyl)glucoside—several minor compounds were identified. Among these, two peonidin derivatives and one delphinidin derivative were characterized on the basis of their fragmentation patterns. To the best of our knowledge this is the first report on anthocyanins in artichoke heads consisting of aglycones other than those of cyanidin. Quantification of individual compounds was performed by external calibration. Cyanidin 3-(6′′-malonyl)glucoside was found to be the major anthocyanin in all the samples analyzed. Total anthocyanin content ranged from 8.4 to 1,705.4 mg kg−1 dry mass.
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3.
The solubility of 1,4-naphthoquinone, plumbagin, lawsone, and juglone in supercritical carbon dioxide was determined spectroscopically at 40°C, and in the pressure range 8–18 MPa. Their solubilities at 12 MPa were between 0.3 and 10 g L−1. Plumbagin from Plumbago scandens L. roots was extracted at 40°C and 20 MPa. The extracted plumbagin mass fraction was up to 0.2% in fresh roots but down to about 0.006% in aged roots. n-Hexane and chloroform extraction of such aged roots indicates that the older and dryer the roots are, the stronger they bind plumbagin. Reversed-phase HPLC indicated a relatively pure plumbagin extract with supercritical carbon dioxide.
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4.
A cobalt hexacyanoferrate (CoHCF)-modified graphite paraffin wax composite electrode was prepared by a new approach. An amine-functionalised
graphite powder was used for the fabrication of the electrode. A functionalised graphite paraffin wax composite electrode
was prepared and the surface of the electrode was modified with a thin film of CoHCF. Various parameters that influence the
electrochemical behaviour of the modified electrode were studied by varying the background electrolytes, scan rates and pH.
The modified electrode showed good electrocatalytic activity towards the oxidation of butylated hydroxyanisole (BHA) under
optimal conditions and showed a linear response over the range from 7.9 × 10−7 to 1.9 × 10−4 M of BHA with a correlation coefficient of 0.9988. The limit of detection was 1.9 × 10−7 M. Electrocatalytic oxidation of BHA was effective at the modified electrode at a significantly reduced potential and at
a broader pH range. The utility of the modified electrode as an amperometric sensor for the determination of BHA in flow systems
was evaluated by carrying out hydrodynamic and chronoamperometric experiments. The modified electrode showed very good stability
and a longer shelf life. The modified electrode was applied for the determination of BHA in spiked samples of chewing gum
and edible sunflower oil. The advantage of this method is the ease of electrode fabrication, good stability, longer shelf
life, low cost and its diverse application for BHA determination.
Figure Cyclic Voltammogram of () CoHCF modified electrode, () in presence of 1.9 x 10−5 M of BHA and () bare electrode, () in the presence of 1.9 x 10−5 M of BHA in 1.0 M NaCl, pH 7.0 相似文献
5.
n-Butyl benzyl phthalate (BBP) is an endocrine-disrupting chemical. A bacterium species capable of using BBP as the sole source
of carbon and energy was isolated from mangrove sediment. Effects of BBP concentration, pH, temperature, and salinity on BBP
biodegradation were studied. The optimum pH, temperature, and salinity for the BBP biodegradation were 7.0, 37°C, and 15 g L−1, respectively. BBP was completely degraded within 6 days under optimum conditions, and the biodegradation of BBP could be
fitted to a first-order kinetic model. The major metabolites of BBP biodegradation were identified as mono-butyl phthalate,
mono-benzyl phthalate, phthalic acid, and benzoic acid by using high-performance liquid chromatography and gas chromatography–mass
spectrometry. A preliminary metabolic pathway was proposed for the biodegradation of BBP.
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6.
Two novel N-(2-mercapto-1,3,4-thiadiazol-5-yl)-N′-(4-substituted-arylacetyl) urea compounds have been synthesized, characterized by NMR and MS, and used as self-assembly reagents
to form self-assembled monolayers (SAMs) on Pt electrodes. The modified electrodes were characterized by electrochemical methods.
The electrochemical behavior of p-benzenediol at the SAMs electrodes was investigated. It was found that the electrochemical response to p-benzenediol is controlled by diffusion and can be electrocatalyzed to obtain more symmetrical redox peaks and higher voltammetric
current response at the SAMs electrodes, with a peak separation of 80 mV. For p-benzenediol the process at the SAMs electrodes is quasi-reversible with a rate constant of 0.6742 s−1. The SAMs electrodes have been used to determine p-benzenediol by differential pulse voltammetry. The peak current was linear for concentrations of p-benzenediol in the range 1×10−7−5×10−4 mol L−1 and the detection limit was 4.0×10−8 mol L−1. The SAMs electrodes were used to determine p-benzenediol in real photographic developer and in a synthetic waste water sample; the standard addition recovery was in the
range 96.6–100.4%.
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7.
Patricia W. Stege Lorena L. Sombra Germán A. Messina Luis D. Martinez María F. Silva 《Analytical and bioanalytical chemistry》2009,394(2):567-573
Many aromatic compounds can be found in the environment as a result of anthropogenic activities and some of them are highly
toxic. The need to determine low concentrations of pollutants requires analytical methods with high sensitivity, selectivity,
and resolution for application to soil, sediment, water, and other environmental samples. Complex sample preparation involving
analyte isolation and enrichment is generally necessary before the final analysis. The present paper outlines a novel, simple,
low-cost, and environmentally friendly method for the simultaneous determination of p-nitrophenol (PNP), p-aminophenol (PAP), and hydroquinone (HQ) by micellar electrokinetic capillary chromatography after preconcentration by cloud
point extraction. Enrichment factors of 180 to 200 were achieved. The limits of detection of the analytes for the preconcentration
of 50-ml sample volume were 0.10 μg L−1 for PNP, 0.20 μg L−1 for PAP, and 0.16 μg L−1 for HQ. The optimized procedure was applied to the determination of phenolic pollutants in natural waters from San Luis,
Argentina.
Figure Schematic representation of the cloud point extraction process. 相似文献
8.
A supramolecular catalytic kinetic spectrofluorimetric method was developed for the determination of platinum(IV) and the
possible mechanism of catalytic reaction was discussed. The method was based on the fluorescence-enhancing reaction of salicylaldehyde
furfuralhydrazone (SAFH) with potassium bromate, which was catalysed by platinum(IV) in a water–ethanol medium. β–Cyclodextrin (β-CD) obviously sensitized the determination at pH 5.20 and 25°C. Under optimum conditions, the β-CD–platinum–KBrO3–SAFH supramolecular kinetic catalytic reaction system had excitation and emission maxima at 372 and 461 nm, respectively.
The linear range of this method was 0.60–180 ng ml−1 with a relative standard deviation of 1.2%, and the detection limit was 0.18 ng ml−1. Investigation of the mechanism and the effects of interferences is presented. The proposed method was applied successfully
to determine trace platinum(IV) in the chemotherapeutic drug cisplatin and serum from patients with satisfactory results.
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9.
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
10.
A nonradioactive 31P nuclear magnetic resonance (NMR) spectroscopy protocol has been developed and used to investigate in vitro autophosphorylation of insulin receptors. Optimum experimental conditions have been explored, and the effects of Mn2+ and phosphocreatine (PCr) on the determination of the phosphorylation reaction have been assayed. The method was used to monitor the time courses of the phosphorylation reaction in solution. The results from this NMR study were in agreement with observations of insulin receptor phosphorylation made by using Western blotting.
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11.
Arya SK Datta M Singh SP Malhotra BD 《Analytical and bioanalytical chemistry》2007,389(7-8):2235-2242
Cholesterol oxidase (ChOx), cholesterol esterase (ChEt), and horseradish peroxidase (HRP) have been co-immobilized covalently
on a self-assembled monolayer (SAM) of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane (AEAPTS) deposited on an indium–tin–oxide (ITO) glass surface. These enzyme-modified
(ChOx-ChEt-HRP/AEAPTS/ITO) biosensing electrodes have been used to estimate cholesteryl oleate from 10 to 500 mg dL−1. The sensitivity, K
m value, and shelf-life of these ChEt-ChOx-HRP/AEAPTS/ITO biosensing electrodes have been found to be 124 nA mg−1 dL, 95.098 mg dL−1 (1.46 mmol L−1), and ten weeks, respectively. The ChEt-ChOx-HRP/AEAPTS/ITO bio-electrodes have been used to estimate total cholesterol in
serum samples.
Figure Covalent immobilization of enzymes onto AEAPTS/ITO surface using EDC/NHS chemistry
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
12.
Ortega-Algar S Ramos-Martos N Molina-Díaz A 《Analytical and bioanalytical chemistry》2008,391(2):715-719
A single optosensing device based on lanthanide-sensitized luminescence was developed for determination of p-aminobenzoic acid (PABA). The method is based on the formation of a complex between PABA and Tb(III) immobilized on the solid
phase (QAE A-25 resin) placed inside the flow cell. NaCl (1 M) was used as carrier solution and HCl (0.05 M) as eluent. The
sample solutions of PABA (100 μL) containing Tb(III) and buffered at pH = 6.0 were injected into the carrier stream and the
luminescence was measured at λ
ex = 290 nm and λ
em = 546 nm. The method shows a linear range from 0.2 to 6.0 μg mL−1 with an RSD of 1.2% (n = 10) and a sampling frequency of 22 h−1. A remarkable characteristic of the method is its high selectivity which allows it to be satisfactorily applied to the analysis
of PABA in pharmaceutical samples without prior treatment.
Figure Typical emission bands of Tb(III) in a solid-phase PABA–Tb(III) luminescence spectrum 相似文献
13.
Pisonero J Kroslakova I Günther D Latkoczy C 《Analytical and bioanalytical chemistry》2006,386(1):12-20
The spatial distribution and concentration of impurities in metallurgical-grade silicon (MG-Si) samples (97–99% w/w Si) were investigated by use of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The spatial resolution
(120 μm) and low limits of detection (mg kg−1) for quality assurance of such materials were studied in detail. The volume-dependent precision and accuracy of non-matrix-matched
calibration for quantification of minor elements, using NIST SRM 610 (silicate standard), indicates that LA-ICP-MS is well
suited to rapid process control of such materials. Quantitative results from LA-ICP-MS were compared with previously reported
literature data obtained by use of ICP-OES and rf-GD-OES. In particular, the distribution of element impurities and their
relationship to their different segregation coefficients in silicon is demonstrated.
Dedicated to Professor Klaus G. Heumann 相似文献
14.
We present here a new accessory for IR transmission measurements of 1H/2H exchange, as an ancillary tool for monitoring structural features of biomolecules in aqueous solution. This new accessory
results from the combination of two dialysis membranes and a conventional liquid cell having two cylinders containing 2H2O buffer. When compared with conventional transmission measurements, carried out either after dissolving lyophilized biomolecules
in 2H2O or after dialyzing the aqueous solution considered against 2H2O buffer, this accessory shows the following advantages: (1) controlled measurements over the initial steps of this isotopic
exchange and absence of molecular aggregation, and (2) smaller sample amounts. This new Fourier transform IR cell can also
be used to analyze ligand–biomolecule and drug–cell interactions.
相似文献
15.
Lapainis T Scanlan C Rubakhin SS Sweedler JV 《Analytical and bioanalytical chemistry》2007,387(1):97-105
A laser-induced native fluorescence detection system optimized for analysis of indolamines and catecholamines by capillary
electrophoresis is described. A hollow-cathode metal vapor laser emitting at 224 nm is used for fluorescence excitation, and
the emitted fluorescence is spectrally distributed by a series of dichroic beam-splitters into three wavelength channels:
250–310 nm, 310–400 nm, and >400 nm. A separate photomultiplier tube is used for detection of the fluorescence in each of
the three wavelength ranges. The instrument provides more information than a single-channel system, without the complexity
associfated with a spectrograph/charge-coupled device-based detector. With this instrument, analytes can be separated and
identified not only on the basis of their electrophoretic migration time but also on the basis of their multichannel signature,
which consists of the ratios of relative fluorescence intensities detected in each wavelength channel. The 224-nm excitation
channel resulted in a detection limit of 40 nmol L−1 for dopamine. The utility of this instrument for single-cell analysis was demonstrated by the detection and identification
of the neurotransmitters in serotonergic LPeD1 and dopaminergic RPeD1 neurons, isolated from the central nervous system of
the well-established neurobiological model Lymnaea stagnalis. Not only can this system detect neurotransmitters in these individual neurons with S/N>50, but analyte identity is confirmed on the basis of spectral characteristics.
Lapainis and Scanlan contributed equally to this work. 相似文献
16.
A synchrotron FTIR microspectroscopy investigation of fungal hyphae grown under optimal and stressed conditions 总被引:1,自引:0,他引:1
Synchrotron FTIR can provide high spatial resolution (<10 μm pixel size) in situ biochemical analyses of intact biotissues,
an area of increasing importance in the post-genomic era, as gene functions and gene networks are coming under direct scrutiny.
With this technique, we can simultaneously assess multiple aspects of cell biochemistry and cytoplasmic composition. In this
paper, we report the first results of our synchrotron FTIR examination of hyphae of three important fungal model systems,
each with sequenced genomes and a wealth of research: Aspergillus, Neurospora, and Rhizopus. We have analyzed the FTIR maps of Aspergillus nidulans cells containing the hypA1 allele, a well-characterized single-gene temperature-sensitive morphogenetic mutation. The hypA1 cells resemble wildtype at 28 °C but have growth defects at 42 °C. We have also investigated Neurospora and Rhizopus cultures grown in media with optimal or elevated pH. Significant differences between the spectra of the three fungi are likely
related to differences in composition and structure. In addition, high spatial resolution synchrotron FTIR spectroscopy provides
an outstanding method for monitoring subtle subcellular changes that accompany environmental stress.
Figure Photomicrographs and FTIR spectra acquired along Rhizopus hyphae grown at pH 6.5 (a) and pH 8.5 (b). Scale bars 50 μm 相似文献
17.
Determination of norfloxacin in human urine by capillary electrophoresis with electrochemiluminescence detection 总被引:3,自引:0,他引:3
A fast and sensitive approach that can be used to detect norfloxacin in human urine using capillary electrophoresis with end-column
electrochemiluminescence (ECL) detection of is described. The separation column was a 75-μm i.d. capillary. The running buffer was 15 mmol L−1 sodium phosphate (pH 8.2). The solution in the detection cell was 50 mmol L−1 sodium phosphate (pH 8.0) and 5 mmol L−1
The ECL intensity varied linearly with norfloxacin concentration from 0.05 to 10 μmol L−1. The detection limit (S/N=3) was 0.0048 μmol L−1, and the relative standard deviations of the ECL intensity and the migration time for eleven consecutive injections of 1.0 μmol L−1 norfloxacin (n=11) were 2.6% and 0.8%, respectively. The method was successfully applied to the determination of norfloxacin spiked in human
urine without sample pretreatment. The recoveries were 92.7–97.9%.
相似文献
18.
Cho SK Shim SH Park KR Choi SH Lee S 《Analytical and bioanalytical chemistry》2006,386(7-8):2027-2033
Three hundred and thirty two bacterial colonies were isolated from soil contaminated by an oil spill. All the bacteria were
cultured in a liquid medium individually, and the surface tensions of the media were compared. The bacterium whose culture
medium had the lowest surface tension was identified as Pseudomonas sp. G11. A biosurfactant was produced by cultivation of the Pseudomonas sp. G11 in the LB media. For extraction of the biosurfactant, two solvent systems were used (n-hexane and a 2:1 (v/v) mixture of chloroform/MeOH), and the results were compared. Various experimental conditions (solvent
composition, flow rate, etc.) were tested to optimize the analysis of the biosurfactant by asymmetrical flow field-flow fractionation
(AsFlFFF). The biosurfactant was successfully separated from the culture medium by AsFlFFF when pure water was used as the
carrier. From the retention data, the hydrodynamic diameter (d
H) and molecular weight (M) of the biosurfactant were determined by AsFlFFF. The molecular weight was determined by using pullulans as the calibration
standards. The d
H and M were 49 nm and 2.3 × 105 Da when extracted with n-hexane, and 39 nm and 1.13 × 105 Da when extracted with the 2:1 mixture of chloroform/MeOH, respectively.
Figure Separation of biosurfactant from its culture medium by flow FFF 相似文献
19.
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
20.
Limbut W Hedström M Thavarungkul P Kanatharana P Mattiasson B 《Analytical and bioanalytical chemistry》2007,389(2):517-525
A capacitive biosensor for the detection of bacterial endotoxin has been developed. Endotoxin-neutralizing protein derived
from American horseshoe crab was immobilized to a self-assembled thiol layer on a biosensor transducer (Au). Upon injection
of a sample containing endotoxin, a decrease in the observed capacitive signal was registered. Endotoxin could be determined
under optimum conditions with a detection limit of 1.0 × 10−13 M and linearity ranging from 1.0 × 10−13 to 1.0 × 10−10 M. Good agreement was achieved when applying endotoxin preparations purified from an Escherichia coli cultivation to the capacitive biosensor system, utilizing the conventional method for quantitative endotoxin determination,
the Limulus amebocyte lysate test as a reference. The capacitive biosensor method was statistically tested with the Wilcoxon signed rank test, which proved
the system is acceptable for the quantitative analysis of bacterial endotoxin (P < 0.05).
Figure The flow-injection capacitive biosensor system and the capacitive properties of the transducer surface, where CSAM is the capacitance change of the self-assembled thiol monolayer, CP is the capacitance change of the protein layer, Ca is the capacitance change of the analyte layer and CTotal is the total capacitance change measured at the working electrode/solution interface (modified from Limbut et al., 2006.
Biosens Bioelectron 22: 233-240) 相似文献