Browsing by Author "EL-Bagary R."

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    Field-amplified sample stacking cyclodextrin modified capillary electrophoresis for quantitative determination of diastereomeric saponins
    (Springer Netherlands, 2014) Emara S.; Masujima T.; Zarad W.; Mohamed K.; Kamal M.; Fouad M.; EL-Bagary R.; Faculty of Pharmacy; Pharmaceutical Chemistry Department; Misr International University; Km 28 Ismailia Road; Cairo; Egypt; P.I. Laboratory Single Cell MS; RIKEN Quantitative Biology Center; 6-2-3; Furuedai; Suita; Osaka; 565-0874; Japan; Faculty of Pharmacy; Pharmacognosy Department; Assiut University; Assiut; 71526; Egypt; Faculty of Pharmacy; Pharmaceutical Analytical Chemistry Department; Modern Sciences and Arts University; 26 July Mehwar Road Intersection with Wahat Road; 6 October City; Egypt; Faculty of Pharmacy; Pharmaceutical Chemistry Department; Cairo University; Kasr El Aini St.; Cairo; 11562; Egypt
    Successful simultaneous diastereomeric separation and sensitive determination of two pairs of triterpenoidal saponins have been achieved by capillary electrophoresis (CE) using ?-cyclodextrin (?-CD) as a stereoselective agent to cooperate with borate complexation. A usual technique for isolation and group separation of saponins was developed as an appropriate purification step prior to the determination of individual saponins by CE. Soyasaponin I (S1), azukisaponin V (S2), bersimoside I (S3) and bersimoside II (S4) could be well separated within 14 min in a fused-silica capillary (60 cm long to the detector with an additional 10 cm to the cathode; 75 ?m i.d.). The background electrolyte was borate buffer (80 mM, pH 10), containing 24 mM ?-CD. The separation voltage was 14 kV with a detection wavelength of 195 nm. The sample was electrokinetically injected using a voltage of 16 kV for 12 s. Methanol (70%) was used as the diluent for field-amplified sample stacking after hydrodynamic injection of short water plug (5 cm, 4 s). The method was partially validated for linearity, repeatability, reproducibility, limits of detection and limits of quantification. The correlation coefficients of the calibration curves were all >0.998, and the recoveries were from 98.23 to 96.21%. The Author [2013]. Published by Oxford University Press. All rights reserved.
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    On-line solid-phase enrichment coupled to packed reactor flow injection analysis in a green analytical procedure to determine low levels of folic acid using fluorescence detection
    (2012) Emara S.; Masujima T.; Zarad W.; Kamal M.; EL-Bagary R.; Pharmaceutical Chemistry Department; Faculty of Pharmacy; Misr International University; Km 28 Ismailia Road; Cairo; Egypt; Analytical Molecular Medicine and Devices Laboratory; Hiroshima Univ.; Graduate School of Biomedical Sciences; 1-2-3; Kasumi; Minami-ku; Hiroshima; 734-8551; Japan; Pharmaceutical Analytical Chemistry Department; Faculty of Pharmacy; Modern Sciences and Arts University; 26 July Mehwar Road intersection with Wahat Road; 6 October City; Egypt; Pharmaceutical Chemistry Department; Faculty of Pharmacy; Cairo University; Kasr El Aini St; Cairo; 11562; Egypt
    Background: Analysis of folic acid (FA) is not an easy task because of its presence in lower concentrations, its lower stability under acidic conditions, and its sensitiveness against light and high temperature. The present study is concerned with the development and validation of an automated environmentally friendly pre-column derivatization combined by solid-phase enrichment (SPEn) to determine low levels of FA.Results: Cerium (IV) trihydroxyhydroperoxide (CTH) as a packed oxidant reactor has been used for oxidative cleavage of FA into highly fluorescent product, 2-amino-4-hydroxypteridine-6-carboxylic acid. FA was injected into a carrier stream of 0.04 M phosphate buffer, pH 3.4 at a flow-rate of 0.25 mL/min. The sample zone containing the analyte was passed through the CTH reactor thermostated at 40�C, and the fluorescent product was trapped and enriched on a head of small ODS column (10 mm x 4.6 mm i.d., 5 ?m particle size). The enriched product was then back-flush eluted by column-switching from the small ODS column to the detector with a greener mobile phase consisting of ethanol and phosphate buffer (0.04M, pH 3.4) in the ratio of 5:95 (v/v). The eluent was monitored fluorimetrically at emission and excitation wavelengths of 463 and 367 nm, respectively. The calibration graph was linear over concentrations of FA in the range of 1.25-50 ng/mL, with a detection limit of 0.49 ng/mL.Conclusion: A new simple and sensitive green analytical procedure including on-line pre-column derivatization combined by SPEn has been developed for the routine quality control and dosage form assay of FA at very low concentration level. The method was a powerful analytical technique that had excellent sensitivity, sufficient accuracy and required relatively simple and inexpensive instrumentation. � 2012 Emara et al.; licensee Chemistry Central Ltd.