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1.
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
2.
A method has been developed for rapidly separating and detecting strychnine and brucine using a poly(dimethysiloxane) (PDMS)
microchip and electrochemical (EC) detection. PDMS microchannels dynamically modified by Brij35 are shown to be more efficient
than native ones. The two analytes are well separated within 90 s in 70 mmol/L acetate buffer (pH 5.5) containing 0.01% (v/v)
Brij35. Detection limits were found to be 1.0 μmol/L for strychnine and 0.2 μmol/L for brucine at S/N=3. The method was used
to determine trace strychnine and brucine in rat serum, and the results obtained correlate well with those obtained via high-performance
liquid chromatography (HPLC).
相似文献
3.
Benko B Kalász H Ludányi K Petroianu G Kuca K Darvas F Tekes K 《Analytical and bioanalytical chemistry》2007,389(4):1243-1247
Metabolic pathways of the oxime K-48 have been elucidated by means of in vitro and in vivo experiments. K-48 exposure to rat
liver microsomal fraction resulted in the formation of a hydroxylated derivative, in addition to a small molecular fragment.
The in vivo metabolism in rats was investigated after intramuscular administration of 50 μmol oxime. K-48 was present in the
rat serum in unchanged form. Similarly, the analysis of rat cerebrospinal fluid indicated the sole occurrence of unchanged
K-48. In contrast, unchanged K-48 was not found in the rat urine, where only the metabolite generated by epoxidation on the
alkyl chain connecting the two pyridinium rings was present. The presence of unchanged K-48 in the serum and cerebrospinal
fluid facilitates quantitative determination using HPLC separation and ultraviolet absorbance detection.
Figure Suggested metabolic pathways of K-48 相似文献
4.
Ragno G Risoli A De Luca M Ioele G Oliverio F 《Analytical and bioanalytical chemistry》2007,389(3):923-929
A novel analytical technique able to determine the anti-ischemic drug trapidil in human serum and urine is proposed. In order
to achieve satisfactory sensitivity and selectivity, an extraction procedure was required to isolate the drug from complex
matrixes such as serum and urine. A solid-phase extraction procedure was investigated to both increase the analyte concentration
and eliminate the interfering molecules present in large amounts in both matrixes. Optimization of the extraction step was
realized by selecting a new polymeric sorbent based on a surface-modified styrene–divinylbenzene polymer which provided fast
and efficient drug extraction. Drug quantification was performed by using the third-order derivative spectra of the SPE eluates.
Absorbance specific signals at 3D335,316 and 3D316 nm for urine and serum, respectively, were demonstrated to be directly proportional to drug concentration and barely affected
by residual matrix interferences. Under the optimized experimental conditions the calibration plots were linear over the concentration
range 0.2–50 μg mL−1. The method was validated by analysis of a series of spiked samples. Accuracy (recovery of 95 and 94% for serum and urine,
respectively) and precision (RSD below 4%) were good.
Figure Assay of Trapidil in biological fluids by SPE and derivative spectrophotometry 相似文献
5.
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
6.
A new spectrofluorimetric method was developed for the determination of trace amounts of lecithin using the ciprofloxacin (CIP)–terbium (Tb3+) ion complex as a fluorescent probe. In a buffer solution at pH=5.60, lecithin can remarkably reduce the fluorescence intensity of the CIP–Tb3+ complex at λ=545 nm. The reduced fluorescence intensity of the Tb3+ ion is proportional to the concentration of lecithin. Optimum conditions for the determination of lecithin were also investigated. The linear range and detection limit for the determination of lecithin were 1.0×10−6–3.0×10−5 mol L−1 and 3.44×10−7 mol L−1, respectively. This method is simple, practical, and relatively free of interference from coexisting substances. Furthermore, it has been successfully applied to assess lecithin in serum samples.
相似文献
7.
The application of near-infrared (NIR) dyes (λ
em > 750 nm) to the analysis of biological samples shows much promise, because the long emission wavelengths of such dyes allow
interferences from biomolecule matrices to be minimized. In this paper, a novel NIR dye, 5,5′-dicarboxy-1,1′-disulfobutyl-3,3,3′,3′-tetramethylindotricarbocyanine
(DCDSTCY) has been developed for the spectrophotometric determination of total protein in serum. Under acidic conditions,
the binding of DCDSTCY to proteins caused a new peak at 878 nm, the height of which was proportional to the concentration
of protein. The linear range of the method was found to be 0.04–0.5 μg mL−1 for bovine serum albumin (BSA) and human serum albumin (HSA), and detection limits of 5 ng mL−1 were obtained for these substances. The maximum binding number of BSA with DCDSTCY was measured to be 133. The method proposed
here has been applied to the quantitation of total protein in serum, and recoveries of 96.6–104% were achieved.
Figure Near-infrared probe for protein determination 相似文献
8.
A new kind of magnetic dextran microsphere (MDMS) with uniform shape and narrow diameter distribution has been prepared from
magnetic iron nanoparticles and dextran. Horseradish peroxidase (HRP) was successfully immobilized on the surface of an MDMS-modified
glassy-carbon electrode (GCE), and the immobilized HRP displayed excellent electrocatalytic activity in the reduction of H2O2 in the presence of the mediator hydroquinone (HQ). The effects of experimental variables such as the concentration of HQ,
solution pH, and the working potential were investigated for optimum analytical performance. This biosensor had a fast response
to H2O2 of less than 10 s and an excellent linear relationship was obtained in the concentration range 0.20 μmol L−1–0.68 mmol L−1, with a detection limit of 0.078 μmol L−1 (S/N = 3) under the optimum conditions. The response showed Michaelis–Menten behavior at larger H2O2 concentrations, and the apparent Michaelis–Menten constant was estimated to be 1.38 mmol L−1. Moreover, the selectivity, stability, and reproducibility of the biosensor were evaluated, with satisfactory results.
Figure Amperometric response of the biosensor to successive additions of H2O2 and the plot of amperometric response vs. H2O2 concentration 相似文献
9.
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
10.
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
11.
The electrochemical behavior of paracetamol in 0.1 M acetate buffer solution (pH 4.6) was investigated at a traditional carbon
paste electrode (TCPE) and a carbon ionic liquid electrode (CILE) fabricated by replacing nonconductive organic binders with
a conductive hydrophobic room temperature ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate (BmimPF6). The results showed that the CILE exhibited better reversibility for the electrochemical redox of paracetamol. The oxidation
potential of paracetamol at the CILE is +0.462 V, which is approximately 232 mV lower than that at the TCPE; the oxidation
peak current response is nine times higher than that at the TCPE. The differential pulse voltammetric determination of paracetamol
at the CILE was established based on this behavior. After optimizing several important parameters controlling the performance
of paracetamol at the CILE, the oxidation peak current versus paracetamol concentration at the CILE showed linearity in the
range from 1.0 μM to 2.0 mM (R
2
= 0.9992) with a detection limit of 0.3 μM (S/N = 3). The method has been applied to the determination of paracetamol in
tablets and urine samples and the average recovery of paracetamol was 98.5% and 99.3%, respectively. The proposed CILE showed
good sensitivity and reproducible response without influence of interferents commonly existing in pharmaceutical and urine
samples.
Figure CV curves of paracetamol illustrate the enhanced electrochemical behavior of paracetamol at the CILE (b), which forms the basis for the differential pulse voltammetric determination of paracetamol 相似文献
12.
Du D Huang X Cai J Zhang A Ding J Chen S 《Analytical and bioanalytical chemistry》2007,387(3):1059-1065
A simple method has been devised for immobilization of acetylcholinesterase (AChE)—covalent bonding to a multiwall carbon
nanotube (MWNT)–cross-linked chitosan composite (CMC)—and a sensitive amperometric sensor for rapid detection of acetylthiocholine
(ATCl) has been based on this. Fourier-transform infrared spectroscopy proved that the native structure of the immobilized
enzyme was preserved on this chemically clean and homogeneous composite film, because of the excellent biocompatibility and
non-toxicity of chitosan. Glutaraldehyde was used as cross-linker to covalently bond the AChE, and efficiently prevented leakage
of the enzyme from the film. Because of the inherent conductive properties of the MWNT, the immobilized AChE had greater affinity
for ATCl and excellent catalytic effect in the hydrolysis of ATCl, with a value of 132 μmol L−1, forming thiocholine, which was then oxidized to produce a detectable and rapid response. Under optimum conditions the amperometric
current increased linearly with the increasing concentration of ATCl in the range 2.0–400 μmol L−1, with a detection limit of 0.10 μmol L−1. Fabrication reproducibility of the sensor was good and the stability was acceptable. The sensor is a promising new tool
for characterization of enzyme inhibitors and for pesticide analysis.
Abstract 相似文献
13.
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
14.
A new method for the highly sensitive and selective determination of boron at nanograms per cubic decimeter levels has been
developed based on the derivatization reaction of boron using salicylaldehyde and 1-amino-8-naphtol-3,6-disulfonate with reversed-phase
partition high-performance liquid chromatography. A detection limit as low as 2.0 nmol/dm3 (22 ng/dm3) was achieved without any preconcentration. No significant interference was observed in the determination of 16 μmol/dm3 of boron with the addition of nine metal ions (AlIII, CuII, CoII, FeII, FeIII, NiII, MnII, VV, ZnII) at concentrations 100 times greater than that of boron without any masking procedure. The proposed method was successfully
applied to the determination of boron in river water, tap water, doubly distilled water, and highly purified water.
Figure Scheme of formation of boron-azomethine-H complex with salicylaldehyde and 1-amino-8-naphthol-3, 6-disulfonate 相似文献
15.
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.
相似文献
16.
Marco Frasconi Monica Mazzarino Francesco Botrè Franco Mazzei 《Analytical and bioanalytical chemistry》2009,394(8):2151-2159
In this paper, we present a surface-plasmon-resonance-based immunosensor for the real-time detection of cortisol and cortisone
levels in urine and saliva samples. The method proposed here is simple, rapid, economic, sensitive, robust, and reproducible
thanks also to the special features of the polycarboxylate-hydrogel-based coatings used for the antibody immobilization. The
sensor surface displays a high level of stability during repeated regeneration and affinity reaction cycles. The immunosensor
shows high specificity for cortisol and cortisone; furthermore, no significant interferences from other steroids with a similar
chemical structure have been observed. The suitability of the hydrogel coating for the prevention of nonspecific binding is
also investigated. A good correlation is noticed between the results obtained by the proposed method and the reference liquid
chromatography/tandem mass spectrometry method for the analysis of cortisol and cortisone in urine and saliva samples. Standard
curves for the detection of cortisol and cortisone in saliva and urine are characterized by a detection limit less than 10 μg l−1, sufficiently sensitive for both clinical and forensic use.
Application of a newly developed SPR immunosensor for the measurement of cortisol in anti-doping analysis 相似文献
17.
The present work describes a headspace single-drop microextraction (HS-SDME) method in conjunction with gas chromatography
electron capture detection (GC–ECD) for the determination of an organophosphate insecticide, chlorpyrifos-ethyl (CPF), in
rat liver. Sample preparation included tissue homogenization with methanol in the presence of anhydrous sodium sulfate in
order to isolate CPF from the matrix, followed by dilution with 10 mL of 0.1 M H2SO4 and headspace microextraction to a 2-μL drop of 1-octanol. The main factors affecting extraction efficiency were optimized
[temperature 90 °C, preheating and extraction times of eight and six minutes, respectively, 2 g of (NH4)2SO4, stirring rate of 1000 rpm, 200 μL of methanolic extract]. The method allows for the separation and quantitation of residue
levels of CPF in the livers of rats exposed orally to that insecticide. Using internal standardization (with chlorpyrifos-methyl
used as an internal standard), the linearity of the method was demonstrated in the range 10–2500 ng g−1 with a correlation coefficient R > 0.996 and a satisfactory level of precision (RSD 3.85%, n = 6). Moreover, the results obtained with the new method do not differ from those obtained with the conventional residue
method used in our laboratory. The feasibility of this HS-SDME approach as an equivalent analytical method for the determination
of CPF in rat liver that possessess advantages such as low cost, low solvent consumption and high throughput was confirmed.
Figure Headspace single-drop microextraction 相似文献
18.
Zaher M Ravelet C Baussanne I Ravel A Grosset C Décout JL Peyrin E 《Analytical and bioanalytical chemistry》2009,393(2):655-660
In this paper, we describe the preparation and the evaluation of a porous graphitic carbon (PGC) column coated with a new
dinaphthyl derivative of neamine for chiral ligand-exchange (LE) chromatography. It was shown that the graphitic surface/dinaphthyl
anchor system efficiently (1.15 μmol/m2) and stably (three months of intensive use) adsorbs the neamine template onto the chromatographic support. The resulting
coated PGC stationary phase showed appreciable LE-based enantioselective properties towards several native amino acids.
Chromatographic separation of methionine enantiomers using a dinaphtyl neamine-based ligand-exchange chiral stationary phase 相似文献
19.
A method based on use of functionalized gold nanoparticles on polyethylenimine film has been developed for colorimetric detection of immunoglobulin G (IgG). The immunogold nanoparticles were immobilized on quartz slides by recognition between antibody and antigen, with the antigen chemically adsorbed on the polyethylenimine film. By measurement of the UV–visible spectra of the immobilized immunogold, detection of h-IgG was achieved. The detection limit for h-IgG by use of this method can be as low as 0.01 μg mL−1. This method is quite promising for numerous applications in immunoassay.
Figure 相似文献
20.
Selective solid-phase extraction of bisphenol A using molecularly imprinted polymers and its application to biological and environmental samples 总被引:1,自引:0,他引:1
Zhang JH Jiang M Zou L Shi D Mei SR Zhu YX Shi Y Dai K Lu B 《Analytical and bioanalytical chemistry》2006,385(4):780-786
Molecularly imprinted polymers (MIPs) were prepared using bisphenol A (BPA) as a template by precipitation polymerization. The polymer that had the highest binding selectivity and ability was used as solid-phase extraction (SPE) sorbents for direct extraction of BPA from different biological and environmental samples (human serum, pig urine, tap water and shrimp). The extraction protocol was optimized and the optimum conditions were as follows: conditioning with 5 mL methanol–acetic acid (3:1), 5 mL methanol, 5 mL acetonitrile and 5 mL water, respectively, loading with 5 mL aqueous samples, washing with 1 mL acetonitrile, and eluting with 3 mL methanol. MIPs can selectively recognize, effectively trap and preconcentrate BPA over a concentration range of 2–20 μM. Recoveries ranged from 94.03 to 105.3 %, with a relative standard deviation lower than 7.9 %. Under the optimal condition, molecularly imprinted SPE recoveries of spiked human serum, pig urine, tap water and shrimp were 65.80, 82.32, 76.00 and 75.97 %, respectively, when aqueous samples were applied directly. Compared with C18 SPE, a better baseline, better high-performance liquid chromatography separation efficiency and higher recoveries were achieved after molecularly imprinted SPE.
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