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Determination of ampicillin and amoxicillin by high-performance thin-layer chromatography

Ghoulipour V., Shokri M, Waqif-Husain S.

Acta Chromatographica

2011

Vol. 23, no. 3

483--498

A simple and fast high-performance thin-layer chromatographic method has been developed for the simultaneous determination of ampicillin and amoxicillin. Titanium(IV) silicate (a synthetic inorganic ion-exchanger)-coated thin-layer chromatography (TLC) plates were used to separate them, employing a mixture of K2HPO4 (0.1 M) + KH2PO4 (0.1 M), 1:1 (υ/υ), as mobile phase. The development time was 18 min. The plates were sprayed with fresh 1% solution of ninhydrin in ethanol. The developed method enables highly contrasted chromatograms with red purple spots in white background. Densitometric measurements were made at wavelength 546 nm using Camag TLC Scanner-3. The ampicillin and amoxicillin recovery of the total procedure were equal to 99.99 and 100.43, respectively. The procedure is quantitatively characterized. Linearities were r2 > 0.9958 and 0.9954 for ampicillin and amoxicillin, respectively, and the relative standard deviations were <0.89 and 0.61, respectively. The limits of detection were 2.9 and 1.5 ng per spot and the limits of quantification were 14.5 and 7.5 ng per spot, respectively. The method is rapid, selective, precise, and accurate and thus can be used for the routine analysis of pharmaceutical preparations in quality control laboratories of the pharmaceutical industry. The method is successfully applied for the determination of ampicillin and amoxicillin in human blood plasma and urine.

Fire influence on the grassland vegetation in Golestan National Park (Alborz Mts. Iran)

Safaian N., Shokri M., Ahmadi M. Z., Atrakchali A., Tavili A.

Polish Journal of Ecology

2005

Vol. 53, nr 3

435-443

Frequent wild fires in mountainous grasslands of Alborz (Iran) influenced the sustainability of habitats and ecological niches of species in this ecosystem. In fact, fire has been a constant event in Golestan National Park in Alborz for a long time (67 fires during 1957 to 1997). Due to importance of this national park in northeastern Iran as a biosphere reserve, the research has been carried out in order to investigate the causes of the fires and the subsequent changes occurred in vegetation and habitat structure. Study was performed in two adjacent: burned and unburned areas in mountains of Alborz. The analysis showed that the vegetation coverage and the above ground biomass in the burned area were significantly greater in comparison to the control area. Whereas, the diversity of vegetation of the two areas did not show significant differences. It was also shown that the coverage of grass species like Stipa pennata L., Festuca valessiana, Avena wiestii Steud. and Aegilops tauschii Coss. increased with respect to the non-burned area. The coverage of woody species like Acanthophyllum pugens, Onobrychis cornuta (L.) Desv., Cotoneaster ovatus Pojark. and Rosa persica Michx. considerably decreased in burned area. Due to increase of annual species of grasses and decrease of woody species, it can be concluded that fire is a preventive factor in succession of ecosystem toward climax and the dominance of grasses can be regarded as a suitable condition for further fire occurrence.