Interactions Between Thrombin and Natural Proudcts of Coreopsis tinctoria Nuttt. and Cistanche deserticola Ma. in Capillary Zone Electrophoresis

Aim A capillary zone electrophoretic method （CZE） was used to determine the interactions between natural products and thrombin. Methods Samples containing natural products and thrombin at various ratios were incubated at 25 ℃ and then were separated by CZE with Tris-acetate buffer at pH 7.2. Each run could be accomplished within 5 min. Results In CZE, the peak width broadened due to the affinity interaction between natural products and thrombin. Compared with positive and negative control, the natural products （CB-1, CB-2） from Coreopsis tinctoria Nuttt. interacted with thrombin; CB-3 from Coreopsis tinctoria Nuttt. and HC-1, HC-2, HC-3 from Cistanche deserticola Ma. did not bind to thrombin. Both qualification and quantification characterizations of the binding were determined. Conclusion The established method is capable of sensitive and fast determination of natural products and thrombin interactions, it can be employed as an alternative method.

Recent advances in screening of enzymes inhibitors based on capillary electrophoresis

Capillary electrophoresis with many advantages plays an important role in pharmaceutical analysis and drug screening. This review gives an overview on the recent advances in the developments and applications of capillary electrophoresis in the field of enzyme inhibitor screening. The period covers 2013 to 2017. Both the pre-capillary enzyme assays and in-capillary enzyme assays which include electrophoretically mediated microanalysis（EMMA） and immobilized enzyme microreactor（IMER） are summarized in this article.

Enantioseparation of Several PharmaceuticalRacemates with High PerformanceCapillary electrophoresis

With high performance capillary electrophoresis using -cyclodextrin or its deriveatives as the chiral selectors, five pairs of drug enantiomers were separated, The PH of the back- gmund electrolyte and the chiral selector concentrations were optimized; and the effect of organic modifier on separation of chlorpheniramine enantiomers was also inver

A covalent modified hydrophilic capillary for enhanced capillary electrophoresis of biopolymers

8-Gluconolactone was covalently coupled to aminopropyl derivatized capillary, which created hydrophilic brushes on the inner wall of the capillary. The coated capillary was shown to generate a stable electroosmotic flow （EOF） in the investigated pH range of 2.0-9.0 and to suppress effectively the adsorption of proteins. And it enabled separation of some biopolymer mixtures including basic proteins, DNA and tryptic digested bovine serum albumin （BSA） within 15 rain with efficiencies up to 450,000 plates/m. The intra- and inter-day reproducibility of the coating referring to the retention times of proteins were satisfactory with mean relative standard deviations （R.S.D.） of 0.8 and 1.7%, respectively. 2009 Yin Mao Wei. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All fights reserved.

A Peptides Migration Model in capillary Zone Electrophoresis

A peptides migration model based on the principle of mechanics is presented in capillary zone electrophoresis (CZE). It is shown that the migration that the (tr) is a function of electric (Q), relative molecular mass (Mr), conformation parameter (Rc) of peptides and electrophoretic condition parameter(A). The conformation parameter is introduced to characterize multifarious shapes owing to the complex conlormation and the various kinds of macromolecules, where Rc≥1/3. The parameters A and Rc can be obtained from experimental data. The times of migration of the nine standard peptides were measured in pH 2.5buffer on different electrophoretic conditions in CZE. The experimental results agreed well with the theoretical prediction.

Separation of Nucleotides in Swine Tissues Using Capillary Zone Electrophoresis

Capillary zone electrophoresis has been applied to the analysis of nucleotides. The effects of buffer concentration. pH and other operating conditions on the separation were investigated and optimized. By using the method, separation and identification of nuclotides in swine tissues were completed.

Improvement on Simultaneous Determination of Cr(III) and Cr(VI) by Capillary Electrophoresis and Chemiluminescence Detection

A sensitive method for the simultaneous determination of Cr(III) and Cr(VI) using in-capillary reaction capillary electrophoresis separation and chemiluminescence detection was developed. The procedures were designed as follows: The sample, hydrochloric acid and sodium hydrogen sulfite solution segments were injected sequentially into the capillary. The reaction of Cr(VI) reduced to Cr(III) by HSO3- occurred inside the capillary after applying the running voltage. According to the migration time difference of both Cr(III) ions moving towards to the cathode (detection end), they could be separated and determined. The limits of detection for chromium(III) and chromium(VI) (S/N = 3) were 6.010-13 mol/L (12 zmol) and 1.910-11 mol/L (380 zmol), respectively.

Separation and Determination of Bases by Capillary Zone Electrophoresis

The present paper covers the separation and determination of cytosine , 9-N-di- hydroxypropyltheophylline , theobromine , adenine , guanine , uracil , theophylline , 1-hydroxyethyl-5-fluorouracil , xanthine , uric acid , 6-mercaptopurine , 5-fluo- rouracil and 1 -propionyloxyuracil by capillary zone electrophoresis. In an uncoated silica capillary(70 cm ×75 μm i. d. effective length 63 cm) , thirteen bases could be separated within 1 1 min under the optimum conditions : 0. 01 mol/L(pH 10. 0) bo- rate buffer, 40℃ , 15 kV, 260 nm and 2 s load. Efficiencies up to 3. 1 ×105 theoreti- cal plates (4. 9 ×105 plates/m) were achieved.

Preparation of β-Cyclodextrin Modified FusedSilica Capillary and Its Application inCapillary Electrophoresis Enantiom eric Separation

A simple type of chiral selector immobilized capillaries was prepared and applied to the separation of some enantiomers by capillary electrophoresis(CE) without chiral selective reagents in a buffer solution. β Cyclodextrin (CD) was bonded to the inner wall of fused silica capillary with the aid of 3 (2 cyclooxypropoxyl) propyl trimethoxy silane or 3 aminopropyltriethoxyl silane as bridge. The synthesis conditions such as reaction temperature, reaction ratios, solvents were optimized. The stability and reproducibility of the CD modified capillaries were studied under different operation conditions. It is satisfactory to apply the capillary to the chiral separation of d,l adrenaline and the atracurium besilate diastereoisomers under the optimized conditions.

Simultaneous Determination of Clonidine Hydrochloride,Hydrochlorothiazide, and Rutin in Zhenju Jiangya Tablet by Capillary Electrophoresis

Aim To develop a method for the determination of three drug components： clonidine hydrochloride, hydrochlorothiazide and rutin in Zhenju Jiangya tablet. Methods An uncoated capillary tube was used to analyze under 20 kV voltage at 20 ℃. The samples were introduced into the capillary tube by hydrodynamic mode applying 50 kPa for 5 s and detected at 210 nm. Results The linear ranges of clonidine hydrochlofide, hydrochlorothiazide, and rutin were 10 μg· mL^-1 - 100μg· mL^-1, 30μg· mL^-1 - 300 μg· mL^- 1, and 30μg · mL^-1 - 300μg · mL^-1, respectively. Inter-day and intra-day RSD were all below 10.5%. The recoveries were 94.96% for clonidine hydrochloride, 84.45% for hydroehlorothiazide, and 89.88 % for rutin. Conclusion Clonidine hydrochloride, hydrochlorothiazide, and rutin are baseline separated. The method is simple and rapid for simultaneous determination of the three drug components in Zhenju Jiangya tablet.

A New Capillary Electrophoresis Apparatus with Piezoelectric Ceramics High Voltage Source and Amperometric Detector

A new capillary electrophoresis apparatus was designed. Piezoelectric ceramics transformer technology was first applied in capillary electrophoresis, a high voltage and stable source was made. Amperometric detector was used in which the working electrode was closely opposite to the end of capillary. The apparatus was characterized in good reproducibility, safety and very low cost.

Simultaneous Detection of 13 Key Bacterial Respiratory Pathogens by Combination of Multiplex PCR and Capillary Electrophoresis

Objective Lower respiratory tract infections continue to pose a significant threat to human health. It is important to accurately and rapidly detect respiratory bacteria. To compensate for the limits of current respiratory bacteria detection methods, we developed a combination of multiplex polymerase chain reaction （PCR） and capillary electrophoresis （MPCE） assay to detect thirteen bacterial pathogens responsible for lower respiratory tract infections, including Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catorrholis, Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Staphylococcus aureus, Mycoplasma pneumoniae, Legionella spp., Bordetella pertussis, Mycobacterium tuberculosis complex, Corynebactefium diphthefiae, and Streptococcus pyogenes. Methods Three multiplex PCR reactions were built, and the products were analyzed by capillary electrophoresis using the high-throughput DNA analyzer. The specificity of the MPCE assay was examined and the detection limit was evaluated using DNA samples from each bacterial strain and the simulative samples of each strain. This assay was further evaluated using 152 clinical specimens and compared with real-time PCR reactions. For this assay, three nested-multiplex-PCRs were used to detect these clinical specimens. Results The detection limits of the MPCE assay for the 13 pathogens were very low and ranged from 10-7 to 10-2 ng/μL. Furthermore, analysis of the 252 clinical specimens yielded a specificity ranging from 96.5%-100.0%, and a sensitivity of 100.0% for the 13 pathogens. Conclusion This study revealed that the MPCE with high specificity and sensitivity. This assay survey of respiratory pathogens. assay is a rapid, reliable, and high-throughput method has great potential in the molecular epidemiological.

p-Hydrazinobenzenesulfonic Acid Derivatives of Carbohydrates andTheir Capillary Zone Electrophoresis

p-Hydrazinobenzenesulfonic acid is explored as a novel ultraviolet labeling reagent for capillary electrophoresis (CE) of mono- and disaccharides. The labeling reaction takes less than 10 minutes and introduces both of absorption and charge groups into the sugars.

Chiral Separation of Chlorpheniramine by Capillary Electrophoresis *L

Aim To study the chiral separation of chlorpheniramine(Chp) by using a mixture of β CD and glutamate β CD as the chiral additive in CE. Methods Mixture of β cyclodextrin and glutamate β cyclodextrin was used as a chiral selector to the separation of chlorpheniramine. The effects of the concentrations of β cyclodextrin and glutamate β cyclodextrin, the voltage and the pH of buffers on the separation of chlorpheniramine were studied. Results The chiral recognization of the mixed chiral selector was better than that of a single selector. At pH below 4, the pH of buffers did not affect the separation and the separation of chlorpheniramine had good reproducibility. Conclusion Using a mixture of β CD and Glu β CD as chiral selector is useful for the enantioseparation of Chp in CE.

Capillary electrophoresis with electrochemiluminescence detection for the analysis of quinolone drugs and pharmacokinetics study

A novel method for the determination of two quinolone drugs norfloxacin （NOR） and levofloxacin （LVX） was described by capillary electrophoresis with electrochemiluminescence detection. The good relationship （r ≥ 0.9991） between peak area and concentration of analytes was established over two orders of magnitude. The limits of detection （LOD, S/N = 3） in standard solution are 4.8 × 10^-7 mol/L for NOR and 6.4 × 10^-7 mol/L for LVX, respectively. The limits of quantitation （LOQ, S/N = 10） in real human urine samples are 1.2 × 10^-6 mol/L for NOR and 1.4 × 10^-6 mol/L for LVX, respectively. The present method was successfully applied to the determination of NOR and LVX in human urine and the studv of oharmacokinetics of NOR.

Determination of Nicotine in Tobacco by Capillary Electrophoresis with Electrochemical Detection

A sensitive, simple and low-cost method based on capillary electrophoresis（CE） with electrochemical（EC） detection at a carbon fiber microdisk electrode（CFE） was developed for the determination of nicotine. Effects of de- tection potential, concentration and pH value of the phosphate buffer, and injection time as well as separation voltage were investigated. Under the optimized conditions： a detection potential of 1.20 V, 40 rnmol/L phosphate buffer（pH 2.0）, a sample injection time of 10 s at 10 kV and a separation voltage of 16 kV, the linear range obtained was from 5.0×10^-7 mol/L to 1.0×10^-4 mol/L with a correlation coefficient of 0.9989 and the limit of detection（LOD, S/N=3） obtained was 5.0×10^-8 mol/L. The method was also used to determine the nicotine in cigarettes. Nicotine amount ranged from 0.211 mg/g to 0.583 mg/g in the pipe tobacco of seven brands of cigarette and the amount in one ciga- rette varied from 0.136 mg/cigarette to 0.428 mg/cigarette.

A novel method for Co(Ⅱ) and Cu(Ⅱ) analysis by capillary electrophoresis with chemiluminescence detection

Based on the fact that some metal ions can catalyze the chemiluminescence(CL)reaction of luminol with K_3Fe(CN)_6,a novel capillary electrophoresis CL method was developed for the determination of Co(Ⅱ)and Cu(Ⅱ).The separation was carried out with a 10 mmol/L sodium acetate solution containing 0.8 mmol/L luminol and 2.0 mmol/Lα-HIBA(adjusted to pH 4.8 by HAc solution).The post-capillary reagent was 2.0 mmol/L K_3Fe(CN)_6 which was adjusted to pH 13.0 by NaOH solution.Under the optimum conditions,the detection limits(S/N=3)for Co(Ⅱ)and Cu(Ⅱ)were 7.5×10^(-11)mol/L and 7.5×10^(-9)mol/L,with the linear range of 7.5×10^(-9)mol/L to 1.0×10^(-6)mol/L and 7.5×10^(-8)mol/L to 5.0×10^(-5)mol/L, respectively.

Studies on Human Immunoglobulin G from GBS Patient (Ⅲ)-The Determination of Molecular Weight of Human Immunoglobulin G by Capillary SDS Gel Electrophoresis

Guillain-Barre syndrome (GBS) is considered to be an autoimmune disorder of peripheralnervous system. In this paper. capillary SDS gel electrophoresis was performed on neutral coatedfused-silica capillary to determine the molecular weight of purified IgG samples from GBS patient.

Simultaneous determination of flavonoids and anthraquinones in chrysanthemum by capillary electrophoresis with amperometry detection

A high-performance capillary electrophoresis with amperometry detection method （CE-AD） has been developed for the analysis of flavonoids and anthraquinones （emodin, kaempferol, apigenin, luteolin and rhein） in chrysanthemum. Under optimum conditions, these five analytes were base-line separated within 17 min using a borate-phosphate running buffer （1.5 ×10^-2 mol/L borate-3× 10^-2 mol/L phosphate running buffer, pH 9.0） at a working potential of ＋0.90 V （vs. SCE） and a separation voltage of 19 kV. The linear relationship between concentration and current response was obtained with detection limits （S/N = 3） ranging from 1.0 × 10^-7 to 2.1 × 10^-7 g/mL for all analytes. This proposed method was successfully used in the analysis of four kinds of chrysanthemum with relatively simple extraction procedures, the assay results were satisfactory.

Study on Rhizoma Chuanxiong based on capillary electrophoresis with amperometric detection

A high-performance capillary electrophoresis with amperometric detection(CE-AD) method has been developed for the analysis of seven bioactive ingredients,namely ferulic acid(FA),vanillin,vanillic acid,p-hydroxybenzoic acid,caffeic acid,gallic acid and protocatechuic acid,in Rhizoma Chuanxiong.The effects of several factors such as the acidity and concentration of running buffer,the separation voltage,the applied potential to working electrode and the injection time were investigated.Under the optimum condit...