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1.
Glucose is an important regulator of cell growth and metabolism. Uridine diphosphate sugars (UDP-sugars), as the intermediate products of metabolism, play pivotal roles as precursors in the synthesis of complex carbohydrates and glycolipids as well as lectose. It is very important to study their metabolism in cells in clinical biochemistry. A capillary electrophoretic method has been developed for the analysis of UDP-sugars and nucleotides. By using an uncoated capillary (70cm×50μm) and 20 mmol/L borax buffer (pH 9), 4 important UDP-sugars can be analyzed in 15 min at 22 kV with satisfactory precision and sensitivity. The developed method has been applied to analyze UDP-sugars concentrations in lymphocytes, fibroblasts and mesangial cells, and the results show it not only is much better than HPLC method, but also can be used to measure the energy charge of cells. 相似文献
2.
Lizhen Liu Feng Feng Qin Hu Man Chin Paau Yang Liu Zezhong Chen Yunfeng Bai Fangfang Guo Martin M. F. Choi 《Electrophoresis》2015,36(17):2110-2119
CE coupled with laser‐induced fluorescence and UV absorption detections has been applied to study the complexity of as‐synthesized green fluorescent hollow carbon nanoparticles (HC‐NP) samples. The effects of pH, type, and concentration of the run buffer and SDS on the separation of HC‐NP are studied in detail. It is observed that phosphate run buffer is more effective in separating the HC‐NP and the optimal run buffer is found to be 30 mM phosphate and 10 mM SDS at pH 9.0. The CE separation of this HC‐NP is based on the difference in size and electrophoretic mobility of HC‐NP. Some selected HC‐NP fractions are collected and further characterized by UV‐visible absorption and photoluminescence (PL) spectroscopy, MS, and transmission electron microscopy. The fractionated HC‐NP show profound differences in absorption, emission characteristics, and PL quantum yield that would have been otherwise misled by studying the complex mixture alone. It is anticipated that our CE methodology will open a new initiative on extensive studies of individual HC‐NP species in the biomedical, catalysis, electronic, and optical device, energy storage, material, and sensing field. 相似文献
3.
陈义 《中国科学B辑(英文版)》1998,41(1):71-76
Glycoproteinsareknowntobeanimportantgroupoffunctionalmacromoleculesinbiologicalsystems,butitismoredifficulttoanalyzethemthannormalproteins.Themostseriousproblemliesintheanalysisoftheirmicroheterogeneitywhichisaspecialphenomenonofglycoconjugates.Differ… 相似文献
4.
Oszwałdowski S Zawistowska-Gibuła K Roberts KP 《Analytical and bioanalytical chemistry》2011,399(8):2831-2842
In the present work, CdSe nanocrystals (NCs) synthesized with a trioctylphosphine surface passivation layer were modified
using amphiphilic molecules to form a surface bilayer capable of providing stable NCs aqueous solutions. Such modified nanocrystals
were used as a test solute in order to analyze new electrophoretic phenomena, by applying a micellar plug as a separation
tool for discriminating nanocrystals between micellar and micelle-free zones during electrophoresis. The distribution of NCs
between both zones depended on the affinity of nanocrystals towards the micellar zone, and this relies on the kind of surface
ligands attached to the NCs, as well as electrophoretic conditions applied. In this case, the NCs that migrated within a micellar
zone can be focused using a preconcentration mechanism. By modifying electrophoretic conditions, NCs were forced to migrate
outside the micellar zone in the form of a typical CZE peak. In this situation, a two-order difference in separation efficiencies,
in terms of theoretical plates, was observed between focused NCs (N ~ 107) and a typical CZE peak for NCs (N ~ 105). By applying the amino-functionalized NCs the preconcentration of NCs, using a micellar plug, was examined, with the conclusion
that preconcentration efficiency, in terms of the enhancement factor for peak height (SEFheight) can be, at least 20. The distribution effect was applied to separate CdSe/ZnS NCs encapsulated in silica, as well as surface-modified
with DNA, which allows the estimation of the yield of conjugation of biologically active molecules to a particle surface. 相似文献
5.
Combining the effects of electrophoresis and electroendosmosis, flavonoids were separated in less than ten minutes in a fused silica capillary tube with a borate buffer adjusted to pH 10. An increase in the concentration of borate from 0.1 to 0.2 M resulted in longer migration times due to a decrease in electroosmotic flow, but also in improved selectivity and higher resolution of flavonoids. The calibration curve of rutin showed a detection limit of 0.02 mg/mL and linearity over its pharmaceutical concentration range. Using an internal standard of known concentration, the content of rutin in a methanolic extract of Sambuci flos could be determined with a coefficient of variation as small as 3.8% by the molar ratio-peak area ratio method. 相似文献
6.
The performance of pyromellitic electrolyte for capillary zone electrophoresis of inorganic selenium species in the presence of selected common anions with indirect UV detection was investigated. The separation was achieved with pyromellitic electrolyte at pH 8.8 and hexamethonium hydroxide as the electroosmotic flow modifier. Obtained detection limits of 0.17 microg ml(-1) for Se(VI) and 0.29 microg ml(-1) for Se(IV) were improved by a factor of 5-7 in comparison with chromate electrolyte, which has been mainly employed for selenium analysis. Good resolution for nitrate-Se(VI) peaks were obtained. 相似文献
7.
M. N. Grigor’eva S. A. Stel’makh L. U. Bazaron D. M. Mognonov 《Polymer Science Series B》2014,56(3):269-273
The dependence of Huggins constant k′ of dilute polyhexamethyleneguanidine hydrochloride solutions on the synthesis duration and monomer molar ratio is determined. It is established that a partially branched polymer is formed at even an equimolar ratio of the monomers, a result that is testified by the rise of k′ after 7 h synthesis from 0.35 to 0.80 in the absence of a rise in the characteristic viscosity. 相似文献
8.
9.
Bekers O op den Buijsch RA de Vries JE Wijnen PA van Dieijen-Visser MP 《Electrophoresis》2002,23(12):1878-1881
We describe the application of capillary electrophoresis to detect DNA fragments, obtained after amplifying a part of the apolipoprotein E (apoE) gene with polymerase chain reaction (PCR). Compared to conventional agarose slab gel electrophoresis (AGE), CE appears the method of choice with regard to resolution and sensitivity, to detect DNA fragments in the range of 20-100 base pairs. Especially discrimination between apoE2/E2 and apoE2/E3 genotypes is more reliable with CE than with AGE, this being of great clinical value in the diagnosis of familiary dysbetalipoproteinemia. 相似文献
10.
11.
Capillary electrophoretic separation of recombinant granulocyte-colony-stimulating factor glycoforms
Free zone capillary electrophoresis separated recombinant human granulocyte-colony-stimulating factor, expressed in Chinese hamster ovary cells, into two well-resolved species. Following incubation with neuraminidase, these species comigrated, eluting earlier than either of the original two species. This indicated that the observed heterogeneity was caused by different amounts of sialic acid present on the carbohydrate portion of the protein. It was determined that optimum separation occurred in the buffer pH range 7–9. Evidence is also presented to show that these glycoforms migrate in order of increasing numbers of sialic acids present. 相似文献
12.
Capillary electrophoresis (CE) was used to separate polycyclic aromatic sulfur heterocycles (PASHs), a class of compounds
that occurs in fossil fuels and refined products of petroleum. An electric charge was introduced into the compounds through
methylation or phenylation of the sulfur atom. Separations of standard PASHs that are expected to be present in industrially
desulfurized fuels showed that CE possessed a higher resolution than reversed phase liquid chromatography. The CE method can
separate all the monomethylbenzothiophenes; this is not achieved in capillary gas chromatography. A linear relationship was
found between migration time and the calculated volume of the compounds. The PASHs in deeply desulfurized diesel were separated
after preconcentration, and the electropherogram was compared with the chromatograms from GC and HPLC. Finally, derivatized
PASHs are often enantiomeric and the enantiomers can be separated if a suitable cyclodextrin is added to the running buffer. 相似文献
13.
A simple and sensitive capillary electrophoretic method was developed for the separation and determination of sodium methyldithiocarbamate (metham), manganese ethylenebisdithiocarbamate (maneb) and ethyl xanthate in boric acid buffer by direct UV absorbance detection at λ = 254 nm. The separation is dependent on pH and nature of the buffer. The detection limits (S/N = 3) are 1.7 × 10–6 mol/L for ethyl xanthate, 1.3 × 10–6 mol/L for metham and 2.1 × 10–6 mol/L for maneb. The method has been successfully applied to the analysis of wheat samples spiked with maneb and in a commercial sample. 相似文献
14.
The major phenolic diterpenes responsible for the antioxidant properties of rosemary extracts, namely carnosol and carnosic acid, were separated by capillary zone electrophoresis (CZE) using a 56 cm long uncoated fused-silica capillary and a 50 mM disodium tetraborate buffer of pH 10.1. The effect of the buffer type, pH and concentration, and the capillary length on the separation, was studied. Carnosol and carnosic acid were identified in the electrophoregrams of rosemary extracts through their migration times and UV spectra obtained by CZE analysis of pure compounds isolated from a rosemary extract by HPLC fractionation. The CZE method had good reproducibility (relative standard deviation less than 5%) and was applied to compare the contents of carnosol and carnosic acid in solid and oil-dispersed commercial extracts of rosemary and in rosemary leaves. The separation of carnosol and carnosic acid was accomplished in less than 11 min. 相似文献
15.
Chartogne A Reeuwijk B Hofte B van der Heijden R Tjaden UR van der Greef J 《Journal of chromatography. A》2002,959(1-2):289-298
Capillary separations of proteins using carrier ampholytes are performed between an anolyte and a catholyte of same pH (pH 3). Depending upon the concentration of carrier ampholytes used, two different separation processes take place. At a 10% concentration, the high-resolution separation of six model proteins is achieved, which can be described as a transient capillary isoelectric focusing (cIEF) system moving isotachophoretically. The isotachophoretic (ITP) behaviour of the system is evidenced by the influence of the catholyte concentration on the separation. The separation is neither pure cIEF nor pure cITP and the migration order of the proteins results from the influence of both their isolelectric points and their mobilities. 相似文献
16.
A simple and sensitive capillary electrophoretic method was developed for the separation and determination of sodium methyldithiocarbamate (metham), manganese ethylenebisdithiocarbamate (maneb) and ethyl xanthate in boric acid buffer by direct UV absorbance detection at lambda = 254 nm. The separation is dependent on pH and nature of the buffer. The detection limits (S/N = 3) are 1.7 x 10(-6) mol/L for ethyl xanthate, 1.3 x 10(-6) mol/L for metham and 2.1 x 10(-6) mol/L for maneb. The method has been successfully applied to the analysis of wheat samples spiked with maneb and in a commercial sample. 相似文献
17.
Bryant C. Nelson Gary F. Rockwell Thomas Campfield Patrick OGrady Rose M. Hernandez Stephen A. Wise 《Analytica chimica acta》2000,410(1-2):1-10
A capillary electrophoretic (CE) assay for oxalate has been applied to the quantitative determination of free oxalate in amniotic fluid. Indirect absorbance detection of oxalate is accomplished with a chromate-based background electrolyte modified with ethylenediaminetetraacetic acid (EDTA). Detection interference due to the presence of high levels (≈4 mg/ml) of inorganic chloride is eliminated through a direct sample clean-up procedure based on cation (Ag+-form) resins. Separation interference from amniotic fluid proteins is prevented through the use of a simple aqueous-based dilution procedure. This method for the determination of oxalate in amniotic fluid provides precision of ≈5% relative standard deviation (RSD). Within-day precisions for the oxalate response and migration time are better than 3% RSD and 1% RSD, respectively. Between-day precisions for the oxalate response and migration time are better than 6% RSD and 3% RSD, respectively. The analytical recovery of oxalate (1000 ng/ml) spiked into amniotic fluid was better than 96%. The limit of detection (LOD) for the method is ≈100 ng/ml oxalate. This method also shows promising results for the determination of oxalate in human blood plasma samples. 相似文献
18.
Claudia Bendazzoli Elisabetta Mileo Marco Lucarini Stefano Olmo Vanni Cavrini Roberto Gotti 《Mikrochimica acta》2010,169(1-2):23-31
The micellization of the ionic surfactant sodium dodecyl sulfate (SDS) has been investigated in the presence of neutral cyclodextrins by means of capillary electrophoresis (CE). The measurements of electric current allowed the determination of the critical micelle concentration of SDS in the presence of α-, β- and γ-cyclodextrin, and of (2-hydroxypropyl)-β-cyclodextrin and (2,6-di-O-methyl)-β-cyclodextrin. Measurements of the CE current also yields information on the binding of SDS by cyclodextrins. The results are supported by electronic paramagnetic resonance spectroscopy and suggest that the methylated cyclodextrin affects the micellization of SDS in an unconventional way compared to other considered cyclodextrins. The combination of SDS with methylated cyclodextrin can have a profound effect on the reliable application of cyclodextrin-modified micellar electrokinetic chromatography. 相似文献
19.
A Zenker M Galanski T L Bereuter B K Keppler W Lindner 《Journal of chromatography. A》1999,852(1):337-346
cis-Diamminedichloroplatinum(II) (cisplatin) is applied against different kinds of cancer although toxic side effects are known. Screening systems for alternative compounds with higher effectiveness but minimizing toxic side effects are required. We investigated the adduct formation of cisplatin with nucleoside monophosphates, di- and trinucleotides. Capillary electrophoretic separations were performed in a sodium phosphate buffer using an instrument equipped with a diode array detector. Adduct formation results in a significant shift of lambda(max) to lower energy compared to free nucleotides. Therefore, UV spectra are an important tool for peak identification. We could separate and identify all four common nucleotides and their major platinum adducts in a single run demonstrating the suitability of CE for these kinds of investigations. Furthermore, kinetic studies of these reactions are performed. 相似文献
20.
Summary Capillary electrophoresis has been used to separate inorganic (Hg2+) and organic (methyl-, ethyl-, and phenylmercury) mercury compounds as their cysteine complexes. The optimized electrophoretic
separation was performed in fused-silica capillary tubing at 25 kV with 25mm sodium borate buffer (pH 9.3). Identification and quantification of the mercury species at mg L−1 levels was achieved by use of UV detection at 200 nm. The relative standard deviation (n=10) ranged from 0.38 to 0.51% for migration times and from 0.43 to 2.94% for corrected peak areas. Good recovery (>90%) was
obtained for all four mercury species in surface waters, and for inorganic mercury and methylmercury in five- to tenfold diluted
biofluids (urine, saliva, and cerebrospinal fluid). TheLOQ values obtained were too high to be useful for determination of mercury species in real samples.
Presented at Balaton Symposium '01 on High-Performance Separation Methods, Siófok, Hungary, September 2–4, 2001 相似文献