Publications by authors named "Mahmoud F Bahnasy"

The two-tailed cationic surfactant dioctadecyldimethyl ammonium bromide (DODAB) produces semi-permanent coatings that yield strongly reversed electroosmotic flow (EOF), for example -0.31 ± 0.01 cm kV s at pH 3.

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A sequential surfactant bilayer/diblock copolymer coating was previously developed for the separation of proteins. The coating is formed by flushing the capillary with the cationic surfactant dioctadecyldimethylammonium bromide (DODAB) followed by the neutral polymer poly-oxyethylene (POE) stearate. Herein we show the method development and optimization for capillary isoelectric focusing (cIEF) separations based on the developed sequential coating.

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A surfactant bilayer/diblock polymer coating was previously developed for the separation of proteins. The coating consisted of a mixture of the cationic surfactant dioctadecyldimethylammonium bromide (DODAB) and the neutral polymer poly-oxyethylene (POE) 40 stearate (Journal of Chromatography A 1130 (2006) 265-271). Herein an improved method of generating DODAB/POE stearate coatings is demonstrated, which yields more predictable EOF, more stable coatings, greater average efficiencies and easier method development.

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The cationic surfactants didodecyldimethylammonium bromide (DDAB) and dioctadecyldimethyl-ammonium bromide (DODAB) have previously been shown to form semi-permanent coatings that effectively prevent adsorption of cationic proteins in fused silica capillaries with inner diameters of 25-75 µm. This paper investigates the impact that narrower capillary diameters (≤25 µm) have on the stability of surfactant bilayer coatings and the efficiency of separations of model cationic proteins and neurotransmitters. Using a DODAB-coated 5 µm i.

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The two stereo-isomers; quinine and quinidine have been determined in their mixtures in the IR region using chemometric multivariate methods, principal component regression (PCR) and partial least squares (PLS). A training set of thirty synthetic binary mixture solutions in the possible combinations containing 0.0 - 4.

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