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1.
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
2.
A practical biosensor system has been developed for the determination of urinary glucose using a flow-injection analysis (FIA)
amperometric detector and ion-exchange chromatography. Glucose oxidase was immobilized onto porous aminopropyl glass beads
via glutaraldehyde activation to form an immobilized enzyme column. On the basis of its negative charge at pH 5.5, endogenous
urate in urine samples was effectively retained by an upstream anion-exchange resin column. The biosensor system possessed
a sensitivity of 160 ±2.4 RU μM-1 (RU or relative unit is defined as 2.86 μV at the detection output) for glucose with a minimum detection level of 10 μM.
When applied for the determination of urinary glucose, the result obtained compared very well with that of the widely accepted
hexokinase assay. The immobilized glucose oxidase could be reused for more than 1000 repeated analyses without losing its
original activity. The reuse of the acetate anion-exchange column before replacement would be about 25–30 analyses. Acetaminophen
and ascorbic acid were also effectively adsorbed by the acetate anion exchanger. The introduction of this type of anion exchanger
thus greatly improved the selectivity of the FIA biosensor system and fostered its applicability for the determination of
glucose in urine samples. 相似文献
3.
Summary Packed columns containing microparticles provide high column efficiency per unit time and strong retention characteristics
compared with open tubular columns, and they are favored for fast separations. Nonporous particles eliminate the contribution
of solute mass transfer resistance in the intraparticle void volume characteristic of porous particles, and they should be
more suitable for fast separations. In this paper, the evaluation of nonporous silica particles of sizes ranging from 5 to
25 μm in packed capillary columns for fast supercritical fluid chromatography (SFC) using neat CO2 is reported. These particles were first deactivated using polymethyl-hydrosiloxanes and then encapsulated with a methylphenylpolysiloxane
stationary phase. The retention factors, column efficiencies, column efficiencies per unit time, separation resolution, and
separation resolution per unit time for fast SFC were determined for various length capillaries packed with various sizes
of polymerencapsulated nonporous particles. It was found that 15 μm nonporous particles provided the highest column efficiency
per unit time and resolution per unit time for fast packed capillary SFC. Under certain conditions, separations were completed
in less than 1 min. Several thermally labile silylation reagent samples were separated in times less than 5 min.
Presented at the 21st ISC held in Stuttgart, Germany, 15th–20th September, 1996 相似文献
4.
Arizaga Rodríguez S Blanco González E Alvarez Llamas G Montes-Bayón M Sanz-Medel A 《Analytical and bioanalytical chemistry》2005,383(3):390-397
Two methods for separation of transferrin (Tf) sialoforms, capillary electrophoresis (CE) and high performance liquid chromatography
(HPLC) with conventional UV absorbance detection, have been investigated and compared. First, conditions affecting the separation
of the Tf isoforms by capillary zone electrophoresis and HPLC were carefully optimized. The use of 15 mmol L−1 borate buffer (pH 8.4) containing 3 mmol L−1 diaminobutane (DAB) as additive enabled good separation of the Tf isoforms by CE (75 cm×50 μm i.d. fused silica capillary)
at 25 kV. In HPLC, a gradient of ammonium acetate (from 0 to 250 mmol L−1 in 45 min) buffered at pH 6 (Tris-HCl) proved suitable for separation of Tf isoforms on a Mono-Q HR 5/5 anion-exchange column.
On-line specific detection of the iron associated with the different Tf isoforms, after Fe saturation, by inductively coupled
plasma mass spectrometry (ICP–MS) was studied in detail to compare its analytical performance with UV detection. For both
CE and HPLC an octapole reaction system (ORS) ICP–MS instrument was used to minimize polyatomic interferences on the 56Fe major isotope. Limits of detection of the different isoforms were in the range of 0.02–0.04 μmol L−1 Tf for HPLC–ICP (ORS)–MS. This hybrid technique proved more selective and reliable detection of transferrin isoforms with
2, 3, 4, 5, and 6 sialic acid residues (S2, S3, S4, S5, and S6) in real serum samples. Interesting results from iron speciation of Tf in serum from healthy individuals and from pregnant
women are given. 相似文献
5.
M. J. e. Souza D. R. Nogueira L. M. Silva M. Z. Arend P. S. Souza Filho A. M. Bergold 《Chromatographia》2007,65(7-8):401-406
An isocratic high-performance liquid chromatographic method has been developed for assay of ceftiofur sodium in drug substance
and in sterile powder for injection. Chromatography was performed on a 250 mm × 4.6 mm, 5 μm particle, C18 column with a 78:22 (v/v) mixture of 0.02 m disodium hydrogen phosphate buffer (pH adjusted to 6.0 with 85% orthophosphoric acid) and acetonitrile as mobile phase, at
a flow rate of 1.0 mL min−1. The separation was monitored by UV detection at 292 nm. Validation of the method for linearity and range, intra- and inter-day
precision, accuracy, specificity, recovery, robustness, and limits of quantification and detection yielded good results. The
calibration plot was linear from 20.0–120.0 μg mL−1 and the correlation coefficient was 0.9999. It was shown that ceftiofur was degraded under acidic, alkaline, oxidative, and
photolytic conditions. The method was found to be stability-indicating and could be used for routine analysis of ceftiofur
sodium for injection. 相似文献
6.
Al-Hamdi AM Williams JR Al-Kindy SM Pillay AE 《Applied biochemistry and biotechnology》2006,135(3):209-218
A rapid reversed-phase (RP) high-performance liquid chromatography method for the isolation of bilirubin from its photoproducts
(e.g., biliverdin) is reported. The method is based on isocratic elution using methanol:water as the mobile phase. A 24 full-factorial experimental design approach was adopted. For the optimization, the best separation was obtained using a flow
rate of 1.50 mL/min, a mobile phase of 99∶1 methanol:water (v/v) at pH 3.60, and a 150×4.6 mm id RP (C18) column containing 5-μm particles. These conditions produced the fastest total retention time of 3.38±0.055 min, and other
chromatographic parameters were acceptable. Under the optimum conditions, a linear calibration curve for bilirubin was obtained
over the 1.0–40.0 μg/L concentration range studied. The limit of quantification was 0.79 g/L and the limit of detection was
0.24 μg/L. Bilirubin in solution was monitored by ultraviolet detection at 450 nm. 相似文献
7.
Summary A rapid and simple liquid-chromatographic method has been developed for on-line quantification of amphetamine in biological
fluids. Untreated samples (20 μL) are injected directly into the chromatographic system and purified on a 20 mm×2.1 mm i.d.
pre-column packed with 30 μm Hypersil C18 stationary phase. After clean-up the analyte is transferred to the analytical column (125 mm×4 mm i.d., 5 μm LiChrospher
100 RP18) for derivatization and separation using a mixture of acetonitrile and the derivatization reagent (o-phthaldialdehyde andN-acetyl-L-cysteine) as the mobile phase. The experimental conditions for on-line derivatization and resolution of the amphetamine
have been optimized, and the results have been compared with those obtained by derivatizing the analyte in pre-column mode.
The method described has been applied to the determination of amphetamine in plasma and urine. Good linearity and reproducibility
were obtained in the 0.1–10.0 μg mL−1 concentration range, and limits of detection were 25 ng mL−1 and 10 ng mL−1 with UV and fluorescence detection, respectively. The procedure described is very simple and rapid, because no off-line manipulation
of the sample is required; the total analysis time is approximately 8 min. 相似文献
8.
Summary A new sensitive HPLC-FLD method has been developed and validated for the determination of cisapride in human plasma for a
bioequivalence study. A gradient method was used to remove late-eluting plasma components of no interest. The separation was
performed on a Li-ChroCART 250-4 Purospher RP-18 (5 μm particle) analytical column fitted with a LiChroCART 4-4 Purospher
RP-18 endcapped (5 μm particle) guard column. The excitation and emission wavelengths were 295 and 350 nm during fluorescence
detection. The calibration plot was linear in the range of 5–200 ng mL−1. A demethoxy analogue of cisapride was used as internal standard. 相似文献
9.
Artem U. Kulikov 《Chromatographia》2007,66(5-6):303-309
A simple micellar liquid chromatographic technique for deltamethrin determination was developed and validated. The method
provided to be suitable for deltamethrin determination in pediculicide shampoo. Kromasil C18 column (150 mm×4.6 mm, 5 μm)
and mobile phase −0.12 M sodium dodecyl sulfate with 9% (v/v) 1-butanol were used for deltamethrin separation. Detection wavelength was 265 nm. The retention time was about 15 min. Different
validation parameters were evaluated. The specificity of the method was demonstrated. Linearity was established in the range
10–40 μg L−1. The limits of detection and quantitation were 1.06 and 3.22 μg mL−1, respectively. The method showed excellent accuracy (100.6%) and precision (repeatability) gave a relative standard deviation
of less than 1%. The influence of the various method parameters (robustness study) was also studied. 相似文献
10.
Summary Fast separations of perfluorinated polyethers and polymethylsiloxanes that are composed of 50–80 oligomers were demonstrated
in packed capillary column supercritical fluid chromatography (SFC) using a carbon dioxide mobile phase. Separations were
accomplished within 10 min using a 13 cm×250 μm i.d. column packed with 2 μm porous octadecyl bonded silica (ODS) particles.
Effects of particle diameter of the packing material and pressure programming on separation were investigated, and packed
column SFC was compared with open tubular column SFC. Results show that as the particle diameter was decreased from 5 to 3
to 2 μm and the column length was reduced from 85 to 43 to 13 cm, the separation time could be reduced from 70 to 20 to 10
min while still maintaining similar separation (resolution). Short columns packed with small porous particles are very suitable
for fast SFC separations of polymers. 相似文献
11.
Unsal E Durdu A Elmas B Tuncel M Tuncel A 《Analytical and bioanalytical chemistry》2005,383(6):930-937
In this study, a new affinity high-performance liquid chromatography (HPLC) stationary phase suitable for protein separation
was synthesized. In the first stage of the synthesis, uniform porous poly(2-hydroxyethyl methacrylate-co-ethylene dimethacrylate), poly(HEMA-co-EDM), beads 6.2 μm in size were obtained. Homogeneous distribution of hydroxyl groups in the bead interior was confirmed
by confocal laser scanning microscopy. The plain poly(HEMA-co-EDM) particles gave very low non-specific protein adsorption with albumin. The selected dye ligand Cibacron blue F3G-A (CB
F3G-A) was covalently linked onto the beads via hydroxyl groups. In the batch experiments, albumin adsorption up to 60 mg
BSA/g particles was obtained with the CB F3G-A carrying poly(HEMA-co-EDM) beads. The affinity-HPLC of selected proteins (albumin and lysozyme) was investigated in a 25 mm×4.0-mm inner diameter
column packed with CB F3G-A carrying beads and both proteins were successfully resolved. By a single injection, 200 μg of
protein was loaded and quantitatively eluted from the column. The protein recovery increased with increasing flow rate and
salt concentration of the elution buffer and decreased with the increasing protein feed concentration. During the albumin
elution, theoretical plate numbers up to 30,000 plates/m were achieved by increasing the salt concentration. 相似文献
12.
The purpose of this work is to study the ability of the laser-induced breakdown spectroscopy (LIBS) technique to perform in
situ (without sample preparation) detection of graphite particles circulating in a gas loop used to simulate the cooling gas
circuit of a helium-cooled nuclear reactor. Results obtained with a laboratory scale set up are presented. The experiments
were performed in nitrogen with micrometer-sized particles containing carbon (glucose particles and sodium hydrogenocarbonate
particles). Statistical shot to shot analysis was used to determine the concentration of the analyte. The variation of LIBS
signal as a function of glucose particle diameter showed an underestimation of the signal of particles of diameters larger
than 5 μm. This phenomenon is likely to be correlated to an incomplete vaporization in the laser-induced plasma of particles
of sizes above 5 μm. Analytical measurements were performed with glucose particles and sodium hydrogenocarbonate particles,
and the concentration-based limit of detection of carbon was evaluated to be about 60 μg m−3. 相似文献
13.
A sensitive analytical method was established for the determination of Th and U in activated concrete samples. The method
combines an anion-exchange separation step with an ICP-MS determination technique. In the ICP-MS measurement, a few μg mL–1 of Al and Ca, a few ng mL–1 of Mn, La, Ce, Nd and Pb and pg mL–1 amounts of Li, Zr, Nb and Ba coexisting in the anion-exchange fraction of Th and U did not interfere. No adverse interference
effects were observed in real sample analyses. The obtained detection limits (3σ, n = 10) of Th and U were 2.3 and 1.8 pg mL–1, respectively. The analytical precisions for ca. 5 μg g–1 Th and ca. 1 μg g–1 U in real activated concrete samples were equally less than 7% RSD. The accuracies obtained by the analysis of GSJ rock standard
samples were –18.1 to 0.4% for the Th determination and –14.0 to –5.7% for the U determination. The method uses the conventional
absolute calibration curve. The internal standard calibration is unnecessary.
Received: 14 March 1999 / Revised: 13 July 1999 / Accepted: 15 July 1999 相似文献
14.
A new hydrophilic strong anion-exchange (SAX) stationary phase for HPLC has been synthesized by chemical modification of macroporous 8.0-m monodisperse poly(glycidylmethacrylate-co-ethylenedimethacrylate) beads (PGMA/EDMA). The stationary phase was evaluated in detail to determine its ion-exchange properties, separability, reproducibility, hydrophilicity, and the effect of column loading and pH on the separation and retention of proteins. It was found to have an ion-exchange chromatographic (IEC) retention mechanism. The highest dynamic protein loading capacity of the synthesized SAX packing for BSA was 22.6 mg g–1. Five proteins were separated within 6.0 min using the synthesized SAX resin. The SAX resin was also used for rapid separation and purification of recombinant human stem cell factor (rhSCF) from a crude extract solution in only one step. The purity of the purified of rhSCF was >92.4%. 相似文献
15.
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
16.
Summary An oxalic acid-α-hydroxyisobutyric acid eluent has been used for the separation and determination of rare-earth elements by
high-performance ion-exchange chromatography. Fifteen rare-earth elements were separated within less than 25 min on a 150×4.6
mm i.d. column packed with 5-μm sulfonic acid-bonded silica particles by elution with a combined gradient of 0.60–9.0 mM oxalic
acid and 19.0–5.0 mM α-hydroxyisobutyric acid at pH 4.6. Detection and quantitation of the separated rare-earth elements was
accomplished by visible-absorbance measurements at 600 nm after postcolumn reaction with arsenazo I. The gradient of the two
complexing agents was optimized to enable the separation of yttrium(III) without interference from other elements, especially
dysprosium(III) and terbium(III). Mass detection limits of the elements were in the range of 2–4 ng. Finally, the chromatographic
system was applied to the quantitative analysis of rare-earth elements in monazite and xenotime. 相似文献
17.
Summary Capillary GC of metal chelates of diethyl dithiocarbamate (DDTC) was examined on a methylsilicone DB-1 column, (25 meter,
0.2 mm. i.d) with a film thickness of 0.25 μm. Elution was carried out at the initial column temperature of 180°C and programmed
at 5°C min−1 to 260°C. Detection was by FID or ECD. Symmetrical peaks with base line separation were obtained with the metal chelates
of copper(II), nickel(II), cobalt(III), manganese(II) and chromium(III). The ECD gave better sensitivity than the FID with
a linear calibration range of 5–50 μg mL−1 and detection limits 2.0–6.0 μg mL−1, corresponding to 111–333 pg of metal ion reaching the detector. The method was applied to the determination of metal ions
in water and pharmaceutical preparations with a coefficient of variation (CV) within 4.0%. When compared with a standard flame
AAS method the results revealed no significant difference. 相似文献
18.
Summary Short columns packed with highly crosslinked 2.3 μm poly-styrene/divinylbenzene (PS/DVB) particles were used for rapid and
efficient separation of proteins and peptides by reversed-phase high-performance liquid chromatography at elevated temperatures.
Enhancement of the diffusivities of the sample components at elevated temperatures together with the short diffusion pathlength
with the micropellicular polymeric stationary phases were responsible for high efficiency, high speed of analysis, and short
column regeneration times. Underivatized PS/DVB beads as well as PS/DVB microspheres which have been modified with polyvinylalcohol
or octadecyl chains on the surface were synthesized, employed, and compared to HY-TACH-C18, a commercially available micropellicular
octadecyl-silica stationary phase, for the separation of proteins, octapeptides and tryptic protein digests. Highest performance
was obtained with the silica- and PS/DVB-based octadecyl stationary phases, which exhibited similar column efficiencies but
different selectivities for proteins and peptides. The minimum detectability at 214 nm and the maximum loading capacity for
ribonuclease A using analytical 30×4.6 mm I.D. columns were 10 ng (0.6 pmol) and 1 μg, respectively. Finally, reversed-phase
HPLC with a 60×2 mm I.D. narrow-bore column packed with micropellicular octadecyl PS/DVB was coupled successfully to electrospray
mass spectrometry at a flow-rate of 0.15 mL min−1 and on-line full-scan mass spectra for molecular mass determination and identification of proteins in the lower picomol range
were obtained. 相似文献
19.
A simple preconcentration approach for quantitative separation and determination of traces of rhenium in geological matrix
using neutron activation analysis is presented in this work. Anionic species of rhenium were collected on small amounts of
anion-exchange resin beads from a large-size geological sample solution followed by neutron irradiation of the resin beads
and measurements of rhenium activity for its quantification. ∼200 mg of resin beads were used to concentrate rhenium from
0.5 to 5 gram of the borehole samples. Radioactive tracers of the analyte directly and in the presence of the matrix were
used to establish the separation process. During the present work the detection limit of rhenium was found to be 10 ng/g. 相似文献
20.
Magnetic molecularly imprinted polymer beads prepared by microwave heating for selective enrichment of β-agonists in pork and pig liver samples 总被引:2,自引:0,他引:2
Novel magnetic molecularly imprinted polymer (MIP) beads using ractopamine as template for use in extraction was developed by microwave heating initiated suspension polymerization. Microwave heating, as an alternative heating source, significantly accelerate the polymerization process. By incorporating magnetic iron oxide, superparamagnetic composite MIP beads with average diameter of 80 μm were obtained. The imprinted beads were then characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis and vibrating sample magnetometer. Highly cross-linked porous surface and good magnetic property were observed. The adsorption isotherm modeling was performed by fitting the data to Freundlich isotherm model. The binding sites measured were 3.24 μmol g−1 and 1.17 μmol g−1 for the magnetic MIP beads and the corresponding non-imprinted magnetic beads, respectively. Cross-selectivity experiments showed the recognition ability of the magnetic MIP beads to analytes is relative to degree of molecular analogy to the template. Finally, this magnetic MIP bead was successfully used for enrichment of ractopamine, isoxsuprine and fenoterol from ultrasonically extracted solution of pork and pig liver followed by high performance chromatography with fluorescence detection. The proposed method presented good linearity and the detection limits was 0.52-1.04 ng mL−1.The recoveries were from 82.0% to 90.0% and from 80.4% to 86.8% for the spiked pork and pig liver, respectively, with the RSDs of 5.8-10.0%. Combination of the specific adsorption property of the MIP material and the magnetic separation provided a powerful analytical tool of simplicity, flexibility, and selectivity. 相似文献