Determination of sildenafil by various methods and in various media is reviewed in this paper. The methods used consist of ultraviolet (UV) spectroscopy, thin layer chromatography (TLC), and high-performance liquid chromatography (HPLC). These methods were used to determine the amount of sildenafil in pharmaceutical preparations, soft drinks, and biological liquids. HPLC was used for evaluation...

in the present study, an oxidative conversion of non-fluorescent dichlorofluoroscein (ldcf) to fluorescent dichlorofluoroscein (dcf) was used for detection of antioxidant properties of plant extracts. the rate of the reaction was followed by monitoring the formation of dcf as a function of time. the antioxidant assay was carried out for different concentrations of gallic acid, salvia mirzayanii...

UNLABELLED An accurate, simple and low-cost image-analysis system has been set up for capturing thin-layer chromatography images, and a software package, TLCQA, has also been developed for both qualitative and quantitative analyses using the acquired image. AVAILABILITY Available upon request from the authors. CONTACT [email protected]

(1991) Vitamin Intake and Health. New York: Marcel Dekker. Hudson TJ and Allen RJ (1984) Determination of pantothenic acid in multivitamin pharmaceutical preparations by reversed-phase high performance liquid chromatography. Journal of Pharmaceutical Sciences 73: 113}115. Koivu TJ, Piironen VI, Henttonen SK and Mattila PH (1997) Determination of phylloquinone in vegetables, fruits and berries b...

Thin-layer chromatography was introduced by Stahl (1956) and has advantages over paper chromatography in speed, resolution, and smaller sample size. Also, the physical nature of the thin layer allows its treatment, where necessary, with strong acids and alkalis. It has been found possible to construct a satisfactory, cheap, and simple apparatus for the preparation of thin layers on glass carrie...

This paper presents a review of the literature concerning development of the stationary phases for thin-layer chromatography (TLC) in the last ten years. The silica gel remains the most important adsorbent for TLC separation. The kinetic properties of the silica-gel thin layer and the new TLC plates have been presented. Other materials used as stationary phase were alumina, zirconium oxide, Flo...

A copy of the license is included in the section entitled " GNU Free Documentation License ". Acknowledgments We thank CONICET, the Secretaría de Ciencia, Tecnologia e Innovación, Gobierno de la Provincia de Chubut and the Consejo Interuniversitario Nacional (CIN) for supporting this development. We also thank Dr. Héctor " Tito " Fernández and Dr. Nazareno Aguirre for their help.

Prepara t ive separation of bile acids has been achieved by adsorption and partition chromatography, and microscale separations have been made by various paper-chromatographic methods (1). Using these methods, good separations and acceptable sensitivity can be achieved. Methods are lacking, however, that permit rapid qualitative analysis of a large number of samples; e.g., for the monitoring of...

With regard to the liquid chromatographic methods described for bile acid analysis, especially with regard to their determination in biological matrices, several approaches for qualitative and quantitative determination have been described. A critical evaluation of the advantages and disadvantages of these methods results in the conclusion that there are speciRc limitations for every applicatio...