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  • Author or Editor: Asma Siddiq x
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A thin-layer chromatographic system comprising of silica gel as stationary phase and 1.0% aqueous urea solution as mobile phase (pH 7.44) has been developed for the mutual separation of five-component mixture of amino acids [lysine (R F = 0.38), histidine (R F = 0.59), leucine (R F = 0.78), alanine (R F = 0.87), and glutamic acid (0.98)]. The presence of foreign substances such as metal cations, anions, and vitamins as impurities in the sample on the separation was also examined. Thin-layer chromatographic parameters such as standard deviation (SD), ΔR F, separation factor (α), and resolution (R S) values of separated components of the mixture of these five amino acids were calculated. The limits of detection for lysine, leucine, and alanine were found to be 1.5 μg spot−1, whereas for histidine and glutamic acid, these were 1.2 μg and 3.0 μg spot−1, respectively. The proposed TLC system is applicable for the identification and separation of amino acids in pharmaceutical formulations.

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A mobile phase system comprising of ethyl acetate and propionic acid in 1:1 (v/v) ratio was identified as the most suitable green mobile phase for selective separation of maltose from fructose, dextrose, galactose, or mannose on precoated silica gel 60 HPTLC plates. The effect of presence of inorganic cations as impurities in the sample was examined for the separation of sugars. The chromatographic parameters like ΔR F, separation factor (α), and resolution (Rs) of separated components of the mixture of maltose-fructose, maltose-dextrose, maltose-galactose, and maltose-mannose were calculated. The limits of detection for fructose, dextrose, and mannose were 7.5 ± 0.41 μg spot−1 and for maltose and galactose were 1.5 ± 0.09 μg spot-1. The proposed method is rapid, sensitive, and free from the use of toxic organic solvents and is therefore environmentally safe. Maltose has been selectively identified in the presence of fructose, dextrose, galactose, and mannose using scanning densitometry.

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