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.

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...

Analysis of Amino Acids in a Single Human Red Blood Cell by Capillary Zone Electrophoresis with Intracellular NDA- derivatization and Electrochemical Detection

A novel method for determination of amino acids in individual human red blood cells has been developed. In this method, the derivatization reagents (NDA and CN-) are introduced into living cells by electroporation. After completion of derivatization, the amino acids in a single cell is determined by capillary zone electrophoresis with end-column amperometric detection.

Analysis of arecoline in Semen Arecae decoction pieces by microchip capillary electrophoresis with contactless conductivity detection

A new method for the determination of arecoline in Semen Arecae decoction pieces by microchip capillary electrophoresis with contactless conductivity detection （MCE-CCD） was proposed. The effects of various electrophoretic operating parameters on the analysis of arecoline were studied. Under the optimal conditions, arecoline was rapidly separated and detected in 1 rain with good linearity over the concentration range of 20 1500 uM （r2=0.9991） and the detection limit of 5 uM （S/N=3）. The method was used for the analysis of arecoline satisfactorily with a recovery of 96.8 -104%.

Capillary electrophoresis with direct chemiluminescence detection for the analysis of catecholamines in human urine

A rapid and sensitive method for the analysis of three catecholamines by capillary electrophoresis （CE） with direct chemiluminescence （CL） detection is described. The detection limits （S/N= 3） were 1.3 × 10^-8 g/mL for isoprenaline, 1.0 × 10^-8g/mL for epinephrine and 2.8 × 10^-8 g/mL for dopamine. The proposed method was successfully applied to the analysis of catecholamines in urine samples of cigarette smokers and nonsmokers. The results showed that there is a close relation between the release of dopamine in human body fluids and cigarette smoking/nonsmoking.

Carbon Fiber-gold/mercury Dual-electrode Detection for Capillary Electrophoresis

A carbon fiber-gold/mercury dual-electrode for capillary electrophoresis is constructed. Cysteine, glutathione, ascorbic acid and uric acid can be detected simultaneously and selectively at the dual-electrode, respectively. The capillary electrophoresis / dual-electrode detection system has been used to determine these compounds in human blood samples.

Assay of Histamine in Single Mast Cells by Capillary Zone Electrophoresis with Electrochemical Detection

Capillary zone electrophoresis was employed for the analysis of histamine in single rat peritoneal mast cells using an amperometric detector. In this method, individual mast cells and then 0.02 mol/L NaOH as a lysing solution are injected into the front end of the separation capillary. A cell injector was constructed for easy injection of single cells. Histamine in single mast cells has been identified and quantified.

Analysis of Glutamic Acid in Cerebrospinal Fluid by Capillary Electrophoresis with High Frequency Conductivity Detection

A rapid method to determine glutamic acid (Glu) in cerebrospinal fluid (CSF) by capillaryelectrophoresis with high frequency conductivity detection (contactless conductivity detection) wasdescribed. The CSF sample was pretreated with silver cation resin to remove high concentration ofCl- ions in CSF. The separation was achieved in the buffer solution of 10 mmol/L Tris and 8mmol/L boric acid at the separation voltage of 20.0 kV. Glu showed linear response in the range of5.0×10-6 to 6.0×10-3 mol/L, the limit of detection was 1.0×10-6 mol/L. The method was used foranalysis Glu in CSF satisfactorily with a recovery of 97.8-98.8%.

Capillary Electrophoretic Determination of Jinggangmycin A in Formulations Using Direct UV Detection

A simple, fast and reliable method was developed for the analysis of jinggangmycin A （validamycin A） in commercial formulations. The running buffer used was acetate buffer （100 mmol/L, pH 4.7） with 15 kV as the applied voltage. The detection was achieved by using direct UV mode at 200 nm and the detection limit was 0.2 μg/mL. Linearity in the concentration range of 5-500 μg/mL was excellent （RE 〉 0.999）. The run-to-run repeatability （n = 3）, as expressed by the relative standard deviation （RSD） for migration times and peak areas were less than 0.5% and 3.0% respectively. The mean recovery ranged from 97.2% to 101.4%.

Electrochemical Detection of Alkaline Phosphatase in BALB/c Mouse Fetal Liver Stromal Cells with Capillary Electrophoresis

A method for determination of alkaline phosphatase (ALP) in BALB/c mouse fetal liver stromal cells has been described based on the catalytic reaction. After the cell extract is incubated with the substrate disodium phenyl phosphate, the reaction product phenol generated by ALP is determined by capillary electrophoresis with electrochemical detection.

Key Conditions in Capillary Electrophoresis of Amino Acids with Indirect Ultraviolet Detection

Key factors for capillary electrophoresis of amino acids with indirect ultraviolet detection were illustrated. Buffer compositions and additives were found to be influential as expected, while buffer pH was shown to be particularly critical to the separation and detection. The effect of pH also depended on the electrophoretic mode used. Ways to obtain recurring and selective were suggested.

Studies of Active Ingredients in Cough Syrup by Capillary Zone Electrophoresis with Amperometric Detection

The present paper covers a simple, reliable and reproducible method, based on capillary zone electrophoresis(CZE) with amperometric detection(AD), for the separation and the determination of ephedrine hydrochloride, promethazine hydrochloride and codeine phosphate. Under the optimal conditions, the three analytes were base-line separated completely within 16 min. Good linear relationships between the peak heights and the concentrations of the three analytes were obtained with the correlation coefficients better than 0 9993. The method was directly applied to the determination of the active ingredients in pharmaceutical preparations and the assay results were satisfactory.

Detection and Separation of Inorganic Cations in Natural, Potable, and Wastewater Samples Using Capillary Zone Electrophoresis with Indirect UV Detection

Capillary zone electrophoresis (CZE) is a sensitive and rapid technique for determining traces of inorganic cations in water samples. CZE with indirect UV-diode array detection (CZE-DAD) was utilized to identify several inorganic cations in natural, potable, and wastewater samples. A pH 4.35 background electrolyte system was employed and consisted of 15 mM imidazole, 8 mM malonic acid, 2 mM 18-crown-6 ether as complexing agents, 10% v/v methanol as an organic modifier with indirect absorbance reference at 214 nm. The CZE method involved electromigration injection at 5 kV for 5 s, a separation voltage of 20 kV at 25℃, and a detection wavelength of 280 nm. Six main cations (ammonium , potassium K+, calcium Ca2+, sodium Na+, magnesium Mg2+, and lead Pb2+) were tested, and all but lead, were detected in the water samples at concentrations between 0.03 and 755 ppm with a detection limit ranging between 0.023 and 0.084 ppm. The successful evaluation of the proposed methodology allowed us to reliably detect and separate six metal ions in different water samples without any pretreatment. All water samples were collected from Northern New York towns and the Raquette River water system, the third longest river in New York State and the largest watershed of the central and western Adirondacks.

Sensitive Determination of Metal Ions in Drinking Water by Capillary Electrophoresis Coupled with Contactless Conductivity Detection Using 18-Crown-6 Ether and Hexadecyltrimethylammonium Bromide as Complexing Reagents

A simple, economical, and sensitive capillary electrophoresis (CE) method integrated with capacitively coupled contactless conductivity detection was developed for the determination of metal ions such as K+, Na+, Mg2+, Sr2+, Ca2+ in drinking water. 18-Crown-6 ether and Hexadecyltrimethylammonium Bromide (CTAB) were employed as complexing reagents. The effects of electrolyte additives, citric acid buffer solution, and other separation conditions of CE were comprehensively investigated and carefully optimized. The best results were obtained in a running buffer solution composed of citric acid (12 mM), 18-crown-6 ether (0.2 mM), and CTAB (0.015 mM) at pH 3.5. Under these conditions, a complete separation of five metal ions was successfully achieved in less than 12 min. The limits of detection for the optimal procedure were determined to be in the range of 0.02 - 0.2 mg·L-1. The repeatability with respect to migration times and peak areas, expressed as relative standard deviations, was better than 2.3% and 5.1%, respectively. Evaluation of the efficiency of the methodology indicated that it was reliable for the determination of metal ions in six different brands of drinking water samples.

A New Method for Decreasing Mass Limit of Detection and Increasing Number of Theoretical Plates in Capillary Electrophoresis with Amperometric Detection

A new method was developed to decrease the mass limit of detection (LOD) and increase the number of theoretical plates (N) in capillary electrophoresis with amperometric detection. When the single microcylinder electrode, the 10 um ID capillary with the etched detection end and the in-capillary alignment were used, the mass LOD for phenol was reduced 124 times and N was increased 36 times in comparison with the normal situation.

Determination of Amino Acids in Single Human Lymphocytes after On-capillary Derivatization by Capillary Zone Electrophoresis with Electrochemical Detection

Amino acids in individual human lymphocytes were determined by capillary zone electrophoresis with electrochemical detection after on-capillary derivatization. In order to inject cells easily, a cell injector was designed. Four amino acids (serine, alanine, taurine, and glycine) in single human lymphocytes have been identified. Quantitation has been accomplished through the use of calibration curves.

A New Immunoassay Method by Capillary Electrophoresis with Enhanced Chemiluminescence Detection

This paper described a new immunoassay method by capillary electrophoresis with enhanced chemiluminescence (CL) detection system based on luminol-hydrogen peroxide reaction catalyzed by horseradish peroxides (HRP). Using para-iodophenol as a CL enhancer, the detection limit of about 1×10-12 mol/L for HRP was achieved, which corresponded to 1.32×10-5 U/mL. In optimal conditions, the free HRP-labeled CA125 antibody (Ab*) and the bound enzyme-labeled complex (Ab*-Ag) were well separated by capillary electrophoresis within 4 min. The assay was successfully used to determine the contents of CA125 in human sera, which were associated with ovarian cancer, and the recoveries of the standard addition experiments were 96 to 109 %.

DNA Separation by Capillary Electrophoresis with Ultraviolet Detection using Mixed Synthetic Polymers

The mixtures of two polymers, poly (N,N-dimethylacrylamide) (PDMA) and polyvinylpyrrolidone (PVP) were synthesized and used as the separation medium for double-stranded and single-stranded DNA fragments by capillary electrophoresis with UV detector. On optimal conditions, 2%w/v PDMA + 2%w/v PVP can be used to separate the doublet 123/124bp in pBR322/Hae III Markers.