Home About us Contact
|
Home About us Contact | ||
|
|
||
Micellar Electrokinetic Chromatographic Method (micellar + electrokinetic_chromatographic_method)
Selected AbstractsSimultaneous determination of digoxin and digitoxin by micellar electrokinetic chromatography and application to drug formulationsJOURNAL OF SEPARATION SCIENCE, JSS, Issue 18 2003Hsiu-Hui Tseng Abstract A simple micellar electrokinetic chromatographic method is described for simultaneous determination of digoxin and digitoxin. The simultaneous analysis of digoxin and digitoxin was performed in Tris buffer (10 mM; pH 9) with 90 mM sodium dodecyl sulfate and 10% isopropyl alcohol as an anionic surfactant and organic modifier. Under these conditions, good separation with high efficiency is achieved in short analysis times. Several parameters affecting the separation of the drugs were studied, including the pH and concentrations of the Tris buffer and sodium dodecyl sulfate. The linear range of the method for the determination of digoxin and digitoxin was over 0.01,0.3 mg/mL; the detection limit (signal to noise ratio = 3; injection 3.5 kPa 3 s) was 4 and 6 ,g/mL, respectively. Application of the proposed method to the determination of digoxin in commercial tablets and in injections proved to be feasible. [source] Analysis of gastrodin and tetramethylpyrazine in traditional Chinese preparations by micellar electrokinetic chromatographyJOURNAL OF SEPARATION SCIENCE, JSS, Issue 6-7 2003Wang Rongying Abstract A simple, rapid, and accurate micellar electrokinetic chromatographic method has been developed for determination of gastrodin and tetramethylpyrazine in three traditional Chinese preparations: Zhennaoning jiaonang, Yangxue shengfa jiaonang, and Xiaoshuan zaizao wan. Running buffer comprising 50 mM sodium tetraborate and 15 M sodium dodecylsulfate (SDS), pH 9.50, was found to be most suitable for the separation. All experiments was performed with a 47 cm (40 cm effective length)×75 ,m ID uncoated fused-silica capillary and UV detection at 200 nm. The linear calibration ranges were 2.5,200 ,g mL,1 (R = 0.999) for gastrodin and 5.0,200 ,g mL,1 (R = 0.997) for tetramethylpyrazine; the detection limits were 0.5 ,g mL,1 and 0.8 ,g mL,1, respectively. Recoveries of the two analytes from the samples, calculated by use of a method described in detail in the text, were between 94.21 and 104.46%. The amounts of gastrodin and tetramethylpyrazine in the preparations were easily determined within 10 min. [source] Rapid and sensitive determination of ephedrine and pseudoephedrine by micellar electrokinetic chromatography with on-line regenerating covalent coatingBIOMEDICAL CHROMATOGRAPHY, Issue 1 2005Xie Jianping Abstract A rapid, sensitive and reproducible micellar electrokinetic chromatographic method using hexamethyldisilazane as on-line regenerating covalent coating was developed for the quanti,cation of ephedrine (E) and pseudoephedrine (PE). E and PE were derivatized with 4-chloro-7-nitrobenzo-2-oxa-1,3-diazol for laser-induced ,uorescence detection. The on-line regenerating covalent coating formed a combinative double coating with the subsequently produced dynamic SDS coating. The total coating can be easily removed and conveniently regenerated on-line. The simple coating procedure was described. By a series of optimization, a running buffer of 20 mm Na2B4O7 + 16 mm SDS was applied for the separation of the derivatives. Linear relationships for E and PE were obtained in the range of 0.044,6.60 µg mL,1 (correlation coef,cients: 0.9975 for E, 0.9981 for PE), and the detection limits for E and PE were 1.71 and 0.67 ng mL,1, respectively. The separation speed, the reproducibility and the sensitivity were much improved over those of other capillary electrophoresis methods more recently reported. The method was applied to the analysis of the two alkaloids in traditional herbal preparations with recoveries in the range 92.8,104.8%. Copyright © 2004 John Wiley & Sons, Ltd. [source] Quantitation of oxcarbazepine and its metabolites in human plasma by micellar electrokinetic chromatographyBIOMEDICAL CHROMATOGRAPHY, Issue 4 2003Vincenzo Pucci Abstract A reliable micellar electrokinetic chromatographic method for the determination of oxcarbazepine and its two main metabolites, 10-hydroxycarbamazepine and 10,11- trans -dihydroxy-10,11-dihydroxycarbamazepine, in human plasma was developed. The separation and determination of the analytes was achieved using a system consisting of 60,mM SDS in phosphate buffer (30,mM, pH 8.0), to which 20% (v/v) methanol was added. Separation was carried out in an uncoated fused-silica capillary with a separation voltage of 25,kV and currents typically less than 40,µA. Spectrophotometric detection was at 205,nm. Isolation of oxcarbazepine and its metabolites from plasma was accomplished by a solid-phase extraction procedure. The mean extraction yield of the analytes from plasma was higher than 94%. The linear correlation coefficients were better than 0.994 for all analytes. The limit of detection was 0.05,µg/mL, the limit of quantitation 0.15,µg/mL. The repeatability for the spiked blank plasma samples was lower than 1.9% and the intermediate precision lower than 2.1%, both expressed as RSD%. The results obtained analysing real plasma samples from epileptic patients under therapy with Tolep® were satisfactory in terms of precision, accuracy and detectability. Copyright© 2003 John Wiley & Sons, Ltd. [source] | ||||||||||