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1.
C. Couriol S. Le Quellec L. Guihard D. Mollé B. Chaufer Y. Prigent 《Chromatographia》2000,52(7-8):465-472
Summary The eluent flow through a fixed bed of a strong anion-exchanger Q Hyper D/F packing has been characterized by mean of the
residence time distribution and the separation conditions of acid whey proteins have been established. Myoglobin under non-retaining
conditions was used as a test protein because its molecular weight was close to that of α-lactalbumin, the target protein
of this study. In the interstitial velocity range of 44–350 cm h−1 a constant reduced height equivalent to a theoretical plate of 13 was observed. Nearly pure fractions of the five main acid
whey proteins were obtained on the preparative scale for a gradient slope of NaCl 1 mM mL−1, in the pH range of 6–8 and an interstitial velocity of 127 cm h−1 (flow rate of 2 mL min−1). A separation focused on a pure fraction of α-lactalbumin was achieved at pH 7.5 and was effective up to an interstitial
velocity of 500 cm h−1 (flow rate of 8 mL min−1). An indepth characterization of α-lactalbumin by electrospray ionization—mass spectrometry showed that 15% of α-lactalbumin
was lactosylated both in the collected fraction and in the acid whey protein concentrate used as feed. 相似文献
2.
A high-performance liquid chromatographic method with evaporative light-scattering detection (ELSD) has been developed for
analysis of spectinomycin and related impurities. Separation of spectinomycin from structurally related impurities was achieved
on a C18 column. The optimized mobile phase was 25 mmol L−1 ammonium acetate (pH 7.5)-methanol, 90:10 (v/v), at a flow rate of 0.6 mL min−1. The temperature of the drift tube of the ELSD was 95°C and the flow rate of carrier gas was 2.2 L min−1. The accuracy, specificity, precision, linearity, sensitivity, and robustness of the method were validated in accordance
with ICH guidelines. In addition to determination of spectinomycin and related impurities, the method is also ideal for determination
of the salts spectinomycin hydrochloride and spectinomycin sulfate. 相似文献
3.
The fully automated on-line trace enrichment of 27 (polar) pollutants, using volumes of up to 1,000 mL, on a polymeric precolumn
followed by liquid chromatography —diode-array detection has been studied. Various parameters influencing the reproducibility
of these large volume injections like breakthrough volume, precolumn capacity, matrix effects, and enrichment flow rate are
discussed. The relative standard deviation of the recoveries after enrichment of 25–500 mL of sample is 1–20%. Enrichment
flow rates up to 15 mL min−1 can be used with an optimum at 10 mL min−1. A pore size of 300 A provides the best results using the polymeric PLRP-S material. The breakthrough volumes show significant
dependence upon the concentration of the analytes in the sample. 相似文献
4.
Umemura T Ueki Y Tsunoda K Katakai A Tamada M Haraguchi H 《Analytical and bioanalytical chemistry》2006,386(3):566-571
Hexyl methacrylate (HMA)-based monolithic semi-micro columns were prepared by in situ polymerization within the confines of
1.02-mm-i.d. silicosteel tubing for reversed-phase and/or precipitation–redissolution liquid chromatography. Practically useful
monolithic columns with adequate separation efficiency, high permeability, and good mechanical strength were successfully
obtained using a polymerization mixture comprising 24% hexyl methacrylate (HMA), 6% ethylene dimethacrylate (EDMA), 44.5%
1-propanol, and 25.5% 1,4-butanediol. The column performance was evaluated through the separations of a series of alkylbenzenes.
At a normal flow rate of 50 μL min−1, the produced HMA-based monolithic columns typically exhibited 3,000 theoretical plates for a 20-cm-long column, and the
pressure drop was generally less than 1 MPa per 20 cm. The monolithic columns were resistant to at least 15 MPa, and could
be properly operated at 15–20 times higher flow rate than normal, reducing the separation time to 1/15–1/20. The HMA-based
monolithic columns were applied to rapid and efficient separations of proteins such as ribonuclease A, cytochrome c, transferrin,
and ovalbumin in the precipitation–redissolution mode. Using a CH3CN gradient elution at a flow rate of 1,000 μL min−1, four proteins were baseline separated within 20 s. 相似文献
5.
Christine Farthing Don Farthing Donald F. Brophy Terri Larus Lena Maynor Itaf Fakhry Todd W. B. Gehr 《Chromatographia》2008,67(5-6):365-368
A simple high-performance liquid chromatographic (HPLC) method was developed for the simultaneous determination of cefepime
and cefazolin in human plasma and dialysate. For component separation, the method utilized a C18 column with an aqueous mobile phase of dibasic potassium hydrogen phosphate (pH 7.0) and methanol gradient at a flow rate
of 1 mL min−1. The method demonstrated linearity from 2.0 to 100.0 μg mL−1 (r > 0.999) with detection limit of 1 μg mL−1 for both cefepime and cefazolin. The method was utilized for evaluation of plasma and dialysate samples in a clinical study
evaluating the dialyzer clearance of cefepime and cefazolin using high-flux hemodialysis with varying blood flow rates in
chronic kidney failure patients undergoing hemodialysis and peritoneal dialysis treatment. 相似文献
6.
Beom Soo Shin Deok Ki Hong Jong Hwan Kwak John Kim Sun Dong Yoo 《Chromatographia》2008,67(3-4):231-235
A rapid and sensitive liquid chromatography-tandem mass spectrometry assay was developed for the determination of a novel
histone deacetylase inhibitor, cyclo{(2S)-2-amino-8-[(aminocarbonyl)hydrazono]decanoyl-1-l-tryptophyl-l-isoleucyl-(2R)-2-piperidinecarbonyl} (SD-2007), in rat serum. The mobile phase consisted of acetonitrile and ammonium formate
(10 mM) (85:15 v/v), and the flow rate was 0.25 mL min−1. Chromatographic separations were achieved by isocratic elution on a C18 column. Multiple reaction monitoring was based on the transition of m/z = 681.8 → 83.6 for SD-2007 and 372.1 → 176.1 for trazodone (internal standard). A linearity was observed over a concentration
range from 2 to 1,000 ng mL−1 (r
2 > 0.999), with the lower limit of quantification at 2 ng mL−1 with 100 μL of rat serum. The mean intra- and inter-day assay accuracy ranged from 98.5–109.7% to 95.2–102.7%, respectively,
and the mean intra- and inter-day precision was between 4.3–11.3% and 2.9–13.3%. The developed assay was applied to a pharmacokinetic
study of SD-2007 in rats after intravenous injection (dose 4 mg kg−1). 相似文献
7.
A. Slováková X. Freiin von Maltzan B. K. Patel A. F. Drake A. J. Hutt 《Chromatographia》1998,48(5-6):369-376
Summary The chromatographic resolution of the enantiomers of sulindac has been achieved using a Chiralpak AD CSP (10 μm, 250×4.6 mm)
with a mobile phase of hexane: ethanol (85∶15 v/v) containing trifluoroacetic acid (0.05% v/v) at a flow rate of 1.0 mL min−1. Under these conditions the enantiomers eluted with separation and resolution factors of 1.43 and 2.46 respectively. Semipreparative
isolation of the enantiomers and their characterization by circular dichroism spectroscopy and NMR, in the presence of a chiral
shift reagent, indicated that the elution order was (−)-(S)- before (+)-(R)-sulindac. The enantiomeric composition of sulindac in urine following administration of the racemic drug to man was determined
by sequential achiral-chiral chromatography. Achiral analysis was carried out using a Spherisorb S5 ODS2 stationary phase
(5 μm, 250×4.6 mm) and a mobile phase of aqueous acetic acid (2% v/v; pH 3.5): acetonitrile: THF (50∶48∶2 by volume) at a
flow rate of 1.0 mL min−1. The HPLC eluate containing sulindac (retention time 4.9 min) was collected and following workup, the enantiomeric composition
of the drug was determined using the CSP. Over the 24 h collection period sulindac was excreted predominantly as theR-enantiomer, but the enantiomeric composition was found to vary markedly with time which is presumably associated with the
complex metabolism of the drug. 相似文献
8.
Summary A sensitive and selective high-performance liquid chromatographic method has been developed for monitoring clozapine levels
in human plasma. Chromatography was performed on a reversed-phase column (C8, 150 mm×4.6 mm i.d., 5 μm) with acetonitrile-aqueous sodium acetate solution, 88∶12 (v/v), as mobile phase; the flow rate was 1 mL min−1. Clozapine oxidation at +800 mV was detected amperometrically. Response was linearly dependent on concentration over the
range 50–1500 ng mL−1 clozapine in plasma. Sample preparation by solid-phase extraction before HPLC analysis gave high extraction yield (94%).
The accuracy and precision of the method were both very good (recovery: 97%;RSD<3.3%). 相似文献
9.
Solid-Phase Extraction and LC with Fluorescence Detection for Analysis of PAHs in Rainwater 总被引:1,自引:0,他引:1
The efficiency of extraction of polycyclic aromatic hydrocarbons (PAHs) from rainwater by solid-phase extraction (SPE) with
three different types of cartridge, and analysis by high-performance liquid chromatography with fluorescence detection, are
discussed in this paper. Three cartridges were investigated but only one was suitable. After equilibration in a desiccator
for 65–80 h or in ambient air for 90–100 h the SPE cartridges were activated with 5 mL dichloromethane then 5 mL 2-propanol.
The volume of sample passed through the cartridges was 50 mL; after loading of the sample the cartridges were dried under
vacuum for approximately 20 min by application of a pressure of 15 mbar to the SPE manifold. The PAHs were eluted with 5 mL
dichloromethane–hexane, 50:50 (v/v). The flow rate used for conditioning, sample loading, and elution was 2.5 mL min−1, achieved by application of a pressure of 6 mbar. For analysis of PAHs in rainwater, recovery was between 67 and 99%, the
relative standard deviation varied between 2 and 5%, and the detection limits of the method were less than 16.9 ng L−1 for several PAHs. These optimum conditions were used for analysis of rainwater collected between June 2002 and May 2003 at
two sites in Alsace (eastern France) and 17 PAHs were quantitatively determined. Concentrations varied between 1.6 and 968.1 ng L−1. 相似文献
10.
A simple flow-injection chemiluminescence method with synergistic enhancement has been investigated for the rapid and sensitive
determination of antipsychotic risperidone. The synergistic action was significant in the chemiluminescence system of luminol—hydrogen
peroxide with risperidone as an enhancer. The increased chemiluminescence intensity was correlated with risperidone concentration
within the range from 10 pg mL−1 to 1.0 ng mL−1 with relative standard deviations lower than 5.0 % and the detection limit of 4 pg mL−1. At a flow rate of 2.0 mL min−1, the flow-injection chemiluminescence method exhibited both a high sensitivity and excellent selectivity giving a throughput
of 120 times per hour. The proposed method was successfully applied to determine the risperidone content in human urine without
any pretreatment. It was found that the excretive amounts of risperidone reached their maximum after taking 2.0 mg of risperidone
for 1 h, with a total excretive ratio of 17.37 % in 8.5 h. 相似文献
11.
Non-isothermal kinetic analysis and feasibilty study of medium grade crude oil field 总被引:1,自引:0,他引:1
M. V. Kök 《Journal of Thermal Analysis and Calorimetry》2008,91(3):745-748
In this research, non-isothermal kinetics and feasibility study of medium grade crude oil is studied in the presence of a
limestone matrix. Experiments were performed at a heating rate of 10°C min−1, whereas the air flow rate was kept constant at 50 mL min−1 in the temperature range of 20 to 600°C (DSC) and 20 to 900°C (TG). In combustion with air, three distinct reaction regions
were identified in all crude oil/limestone mixtures, known as low temperature oxidation (LTO), fuel deposition (FD) and high
temperature oxidation (HTO). The activation energy values were in the order of 5–9 kJ mol−1 in LTO region and 189–229 kJ mol−1 in HTO region. It was concluded that the medium grade crude oil field was not feasible for a self-sustained combustion process. 相似文献
12.
A sensitive and rapid liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) method has been developed
and validated for the determination of mizolastine in human plasma using dipyridamole as the internal standard (I.S.). Plasma
samples were simply pretreated with methanol for deproteinization. Chromatographic separation was performed on an Agilent
Zorbax C18 column with a mobile phase of 10 mM ammonium acetate buffer containing 0.1% formic acid–methanol (20:80, v/v) at a flow rate of 1 mL min−1. The electrospray ionization (ESI) interface was employed in a single quadrupole mass spectrometer. The analytes were protonated
in the positive ESI interface and detected in single ion monitoring (SIM) mode. Chromatographic separation was achieved in
less than 3.5 min. The linearity was established over the range of 0.5–600 ng mL−1. The lower limited of quantification (LLOQ) of the method was 0.5 ng mL−1. The intra- and inter-run standard deviations were both less than 11.2%. The method was applied to study the pharmacokinetics
of the mizolastine sustained-release tablets in healthy volunteers. 相似文献
13.
Summary A simple, rapid and accurate, routine-HPLC method is described for simultaneous determination of acetaminophen, caffeine and
chlorpheniramine maleate in a new tablet formulation Chromatographic separation of the three pharmaceuticals was achieved
on a Hypersil CN column (150×5.0 mm, 5 μm) using a mobile phase comprising a mixture of acetonitrile, an ion-pair solution
and tetrahydrofuran (13:14:87, v/v,pH4.5). The flow-rate was changed from 1.0 mL min−1 (in 0≈7.5 min) to 1.8 mL min−1 (after 3.5 min). was complete in <10 min. The method was validated for system suitability, linearity, accuracy, precision,
limits of detection and quantitation, and robustness. Linearity, accuracy and precision were found to be acceptable over the
ranges 31.6≈315.8 μg mL−1 for acetaminophen, 9.5≈94.6 μg mL−1 for caffeine and 1.4≈13.8 μg mL−1 for chlorpheniramine maleate. 相似文献
14.
Victoria F. Samanidou Emmanouil D. Tsochatzis Ioannis N. Papadoyannis 《Mikrochimica acta》2008,160(4):471-475
An HPLC method was developed and validated for the determination of the cephalosporins cefotaxime and cephalexine in skimmed
bovine milk. The analytical column, Kromasil C18 (250 mm × 4.0 mm, 5 μm) was operated at ambient temperature. Mobile phase consisted of CH3OH-acetate buffer (pH = 4.0) and it was delivered isocratically at a flow rate of 1.0 mL · min−1. Total analysis time was less than 5 min. Caffeine was used as internal standard (5 ng · μL−1). UV detection was performed at 265 nm. Method validation was performed by means of intra-day (n = 5) and inter-day accuracy and precision (n = 8), sensitivity and linearity. Limits of detection (LOD) and limits of quantification (LOQ) were 0.1 and 0.3 ng · μL−1, respectively. The method was applied to the analysis of a veterinary drug (CEPOREX) containing cephalexine. The results
were quite accurate with the relative error varying from −8.0 to −3.5%. Solid-phase extraction was applied to remove all matrix
interference from milk samples. High extraction recoveries (average 84–121%) were achieved by using Abselut NEXUS cartridges
with acetonitrile as eluent and a rinsing step with water and n-butanol. A pre-concentration step was necessary in a 1/10
level to reach the EU MRL concentration level (100 μg · kg−1). RSD values were less than 7% for both cephalosporins.
Correspondence: Ioannis N. Papadoyannis, Laboratory of Analytical Chemistry, Department of Chemistry, Aristotle University
of Thessaloniki, GR-54124 Thessaloniki, Greece 相似文献
15.
Citric acid was thermochemically esterified onto defatted cotton fibre to produce a carboxyl cotton chelator (CCC), which
had been used for extraction of copper prior to its determination by flame atomic absorption spectrometry. The extraction
of copper has been studied under both batch and column methods. Quantitative extraction of copper was achieved in the pH range
4–7. The time needed to extract each sample was less than 30 min by the batch method. The copper extraction capacity of CCC
was found to be 22.7 mg g−1 at optimal pH value. The elution was quantitative with 1 mol L−1 hydrochloric acid. The feasible flow rate of copper-containing solution for quantitative extraction onto the column packed
with CCC was 0.5–4.0 mL min−1, whereas for elution it was less than 1.5 mL min−1. A 100-fold extraction factor could be achieved under the optimal column conditions. The tolerance limits for common metal
ions on the extraction of copper and the time of column reuse were investigated. The proposed method has been successfully
applied for extraction and determination of copper in industrial wastewater and natural water samples. 相似文献
16.
Reversed-phase high-performance liquid chromatography (RPLC) of 17 amino acids and ammonium ion, pre-derivatized with o-phthalaldehyde and ethanethiol, has been investigated using on-line recycled mobile phase. The mobile phase was sodium phosphate
buffer, pH 7.2, containing acetonitrile and 1 mM potassium peroxodisulfate. Fifty consecutive separations on an octadecyl
silica gel column, kept at 35 °C, could be achieved by use of 50 mL mobile phase, at a flow rate of 2.0 mL min−1, without significant changes of peak height and retention times of valine (Val), methionine (Met), and isoleucine (Ileu).
RSD of peak heights and retention times were, respectively, 7.6 and 1.1% for Val, 9.6 and 0.9% for Met, and 4.9 and 0.8% for
Ileu. The volume of mobile phase used was only one sixtieth that used for conventional RPLC. Analysis of Val, Met, and Ileu
in beverages was achieved by use of this method. The results were in agreement with those obtained by conventional RPLC. This
method could be also used for analysis of the other amino acids. 相似文献
17.
Vitor RV Martins MC Figueiredo EC Martins I 《Analytical and bioanalytical chemistry》2011,400(7):2109-2117
A method constituted by molecularly imprinted solid-phase extraction (MISPE) with high-performance liquid chromatography coupled
to diode array detector (HPLC-DAD) was developed for cotinine analysis in saliva samples. For this purpose, the separation
was carried out with a C18 reversed-phase column at 20 °C. The mobile phase which was composed of a mixture of 09:91 (v/v) acetonitrile/phosphate buffer, pH 6.3, was delivered with isocratic flow rate at 1.4 mL min−1. Employing MISPE, the best conditions were achieved with 1.5 mL of saliva plus 1.5 mL of 0.1 mol L−1 of acetate buffer, pH 5.5, which were then passed through a cartridge previously conditioned with 2 mL acetonitrile, 2 mL
methanol, and 2 mL of 0.1 mol L−1 sodium acetate buffer, pH 5.5. The washing was carried out with 1 mL deionized water, 1 mL of 0.1 mol L−1 sodium hydroxide, and 1 mL hexane; finally; the cotinine elution was carried out with 3 mL methanol/water (97.5: 2.5, v/v). Linearity ranged from 30 to 500 ng mL−1 with r > 0.99. Intra-assay, interassay precision, and accuracy ranged from 3.1% to 10.1%, 5.2% to 15.9%, and 99.22% to 111.17%,
respectively. The detection and quantification limits were 10 and 30 ng mL−1, respectively. This investigation has provided a reliable method for routine cotinine determination in saliva, and it is
an important tool for monitoring cigarette smoke exposure in smokers. The method was applied in five smokers’ samples who
consumed around five to 20 cigarettes per day and the values of cotinine in saliva were from 66.7 to 316.16 ng mL−1. 相似文献
18.
Dongmei Zhou Hanfa Zou Jianyi Ni Hailin Wang Li Yang Yukui Zhang 《Chromatographia》1999,50(1-2):27-34
Summary Affinity columns suitable for HPLC were prepared by immobilization of various ligands of protein A, human IgG, human IgM and
pectinase on GMA modified cellulose membrane. The adsorption capacity, affinity efficiency and activity recovery of various
IgGs on these affinity columns were measured. It was observed that the length of the coupling arm plays a very important role
in affinity efficiency, and the effect of eluent flow-rate on adsorption capacity was very small. The protein A column was
exploited for the process monitoring of dog IgG in clinical experiments on immuno-adsorption therapy. A pectinase column was
used for the determination of polygalacturonase inhibiting proteins first purified on a hydroxyapatite column. It took only
about 2.5 min for analysis at a flow-rate of 1.0 mL min−1. The high speed analysis of biopolymers could be performed at a flow rate of 6.0 mL min−1 within 15 s. Membrane affinity chromatography gives good reproducibility, high efficiency, low column-pressure and is rapid.
It can also be used for micro-scale purification of biopolymers. 相似文献
19.
Guzmán-Vázquez de Prada A Loaiza OA Serra B Morales D Martínez-Ruiz P Reviejo AJ Pingarrón JM 《Analytical and bioanalytical chemistry》2007,388(1):227-234
A molecularly imprinted polymer was developed and used for solid-phase extraction (MISPE) of the antihelmintic fenbendazole
in beef liver samples. Detection of the analyte was accomplished using square wave voltammetry (SWV) at a cylindrical carbon
fibre microelectrode (CFME). A mixture of MeOH/HAc (9:1) was employed both as eluent in the MISPE system and as working medium
for electrochemical detection of fenbendazole. The limit of detection was 1.9 × 10−7 mol L−1 (57 μg L−1), which was appropriate for the determination of fenbendazole at the maximum residue level permitted by the European Commission
(500 μg kg−1 in liver). Given that the SW voltammetric analysis could not be directly performed in the sample extract as a consequence
of interference from some sample components, a sample clean-up with a MIP for selectively retaining fenbendazole was performed.
The MIP was synthesized using a 1:8:22 template/methacrylic acid/ethylene glycol dimethacrylate ratio. A Britton–Robinson
Buffer of pH 9.0 was selected for retaining fenbendazole in the MIP cartridges, and an eluent volume of 5.0 mL at a flow rate
of 2.0 mL min−1 was chosen in the elution step. Cross-reactivity with the MIP was observed for other benzimidazoles. The synthesized MIP
exhibited a good selectivity for benzimidazoles with respect to other veterinary drugs. The applicability of the MISPE-SWV
method was tested with beef liver samples, spiked with fenbendazole at 5,000 and 500 μg kg−1. Results obtained for ten different liver samples yielded mean recoveries of (95 ± 12)% and (96 ± 11)% for the upper and
lower concentration level, respectively. 相似文献
20.
A rigid spherical giant-pore poly (glycidyl methacrylate-co-ethylene dimethacrylate) matrix has been prepared by radical suspension–polymerization
on the basis of a novel porogenic mode using superfine particles of calcium carbonate as a solid porogen. Scanning electron
microscopy reveals that the bead has pores as large as 10 μm. The hydrodynamic properties show that this polymeric material
has good strength and a low back pressure of 1.0 MPa at a flow velocity of 3,000 cm h−1. After being modified to be an anion-exchange material, high dynamic binding capacity of plasmid DNA of above 1,000 μg plasmid
per mL of bed by a column of this material, could be obtained comparing to the 150 μg plasmid per mL of bed with a Q-Sepharose
FF column at the same flow rate. Large-scale preparative plasmid separations (2–20 mL) from cell lysate were investigated.
A 75% yield and 94.9% purity of SC plasmid DNA were obtained by a 20 mL column of giant-pore beads at a flow rate of 600 cm h−1. 相似文献