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991.
992.
Khaldun M. Al Azzam Bahruddin Saad Hassan Y. Aboul‐Enein 《Biomedical chromatography : BMC》2010,24(9):977-981
Capillary zone electrophoresis methods for the simultaneous determination of the β‐blocker drugs, atenolol, chlorthalidone and amiloride, in pharmaceutical formulations have been developed. The influences of several factors (buffer pH, concentration, applied voltage, capillary temperature and injection time) were studied. Using phenobarbital as internal standard, the analytes were all separated in less than 4 min. The separation was carried out in normal polarity mode at 25°C, 25 kV and using hydrodynamic injection (10 s). The separation was effected in an uncoated fused‐silica capillary (75 μm i.d. × 52 cm) and a background electrolyte of 25 mm H3PO4 adjusted with 1 m NaOH solution (pH 9.0) and detection at 198 nm. The method was validated with respect to linearity, limit of detection and quantification, accuracy, precision and selectivity. Calibration curves were linear over the range 1–250 μg/mL for atenolol and chlorthalidone and from 2.5–250 μg/mL for amiloride. The relative standard deviations of intra‐ and inter‐day migration times and corrected peak areas were less than 6.0%. The method showed good precision and accuracy and was successfully applied to the simultaneous determination of atenolol, chlorthalidone and amiloride in various pharmaceutical tablets formulations. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
993.
Intikhab A. Ansari 《Physica C: Superconductivity and its Applications》2010,470(11-12):508-510
Here, we report the efficient and feasible analytical method for the generalized Bloch–Gruneisen law in association with Debye temperature and various temperatures range in terms of incomplete gamma function. In addition, our results are in agreement with previous reports as shown in this letter. Bloch–Gruneisen function describes the contribution of electron–phonon interaction to the results of temperature dependence behavior of resistivity for integer and noninteger values of index m. In conclusion, the algorithm is constructed in Fortran 90 language for replicate the variation of temperature dependence of resistivity for pristine MgB2 sample. Moreover, the comparison of numerical results with the proposed method reveals the validity and precision of the method. 相似文献
994.
Mohamed H. Abdel-hay Magda H. Barary Ekram M. Hassan M. Abdel-Hady Elsayed 《光谱学快报》2013,46(8):1025-1044
Abstract Two photometric methods have been described for the assay of three phenothiazine drugs, isothipendyl hydrochloride, dimethothiazine mesylate &; trimeprazine tartarate in their tablets. The first is the differential tartarate in their tablets. The first is the differential spectro-photometric method &; based on the measurement of the absorbance (Δ A-), first derivative (Δ D1?) or second derivative (Δ D2?) values of the sulphoxide product of phenothiazine versus the intact. The second is based on the absorbance measurement of the pink coloured complex formed in a ratio of two drug moles t o one palladium ion. All these values are following Beer's law, which pernits the phenothiazines determination in their tablets with high accuracy. Using t-test &; F-test the results of different methods are of equal accuracy and reproducibility. Both methods complement each ot her during the routine analysis and quality control of the investigated phenothiazine drugs. 相似文献
995.
An improved protocol for the oxidation of sec. alcohols by copper permanganate is described by carrying out the reaction in a homogeneous medium (acetic acid), affording rapid and complete conversion to the ketones. 相似文献
996.
997.
Toma Galaon Dan-Florin Anghel Victor David Hassan Y. Aboul-Enein 《Chromatographia》2013,76(23-24):1623-1630
Non-linear van’t Hoff plots were observed for several benzodiazepines over the usual temperature interval used in RP-LC (10–60 °C), when acetonitrile was added in the mobile phase. Such deviation from linearity was not observed when methanol or isopropanol was added to the mobile phase. Polynomial regressions were applied to fit the experimental data when acetonitrile was used as organic additive in mobile phase. The second-order polynoms may allow finding out the maximum retention depending on temperature, which can be within or out of the normal temperature range used in RP mechanism. A thermodynamic model deriving from the partition of two or more tautomers of the same analyte was proposed to explain this deviation from linearity of van’t Hoff plots. 相似文献
998.
Salah Bouhroum Joseph A. Grondin Stephan Houdier Hassan Lazrek Mohamed Rhazi Abdelouahad Tolaimate 《Journal of carbohydrate chemistry》2013,32(3):309-314
ABSTRACT Hydrazine acetate is shown to effect selective deacetylation on peracetylated glycals like D-xylal, D-glucal, D-galactal and L-rhamnal. It is demonstrated that the observed selectivity on the -4 position cannot be explained by acetyl migration during the reaction. 相似文献
999.
A new method, involving the application of PMR spectrometry for the assay of clofibrate and its capsules, is proposed. Among other peaks the PMR spectrum of clofibrate has a well-defined singlet system which is chosen for quantitative measurement. The principle of the method involves comparing the integral of this signal to that of the sharp singlet (positioned at 0.00 ppm) of hexamethylcyclotrisilazane which is used as internal standard. 相似文献
1000.