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  • Author or Editor: P. Reddy x
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Abstract  

An accurate and rapid radiochemical method has been developed for the determination of silver based on the substoichiometric extraction of its complex with potassium 3-phenylmethyldithiocarbazate into chloroform from pH 5.5 acetate buffer. Microgram amounts of silver could be determined with an average error of ±1.1% and the effect of diverse metal ions was critically examined. The method developed was applied to evaluate the silver content of photofilm washings.

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Abstract  

A rapid radiochemical method for the determination of thallium(III) has been developed based on the substoichiometric extraction of its 13 complex with sodium isopropyl xanthate into chloroform from pH 9 ammonia buffer. The effect of foreign ions on the extraction was also studied. 10 g amounts of thallium were determined with an average error of 1.9%. The method has been successfully applied for the determination of thallium content present in sphalarite ores collected from Jawar Mines, Rajasthan (India).

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Sweet sorghum (Sorghum bicolor (L.) Moench) is a potential raw material for production of ethanol that on blending in petrol is expected to meet the energy demand and address the environmental issues. Well-developed hybrid technology will make the crop remunerative to the farmers. Hence, gene action and best combining female and male parents for sugar yield in sweet sorghum (Sorghum bicolor (L.) Moench) and the association of sugar yield with other agronomic traits was studied in 171 hybrids developed by crossing 19 female parents with nine male parents in line × tester design and evaluated during both rainy and postrainy seasons of 2006. The significant differences between the seasons for all the traits suggested that these traits are greatly influenced by the environment. The lines (female parents) ICSA 38, ICSA 479, ICSA 702, ICSA 675 and ICSA 474 and the restorers (male parents), SSV 74 and SSV 84 combined well for sugar yield during rainy season and the lines, ICSA 702, ICSA 38 and ICSA 474 and the restorers, ICSV 93046, SPV 1411 and ICSV 700 combined well during postrainy season. The magnitude of SCA variance was higher suggesting the importance of non-additive gene action in inheritance of all the traits though both additive and dominant genes controlled overall sugar yield during both the seasons. Hence, selection in early generation would be ineffective and recurrent selection with periodic intercrossing is advocated. However, breeding good combining restorer parents can fetch high sugar yield in postrainy season. There is an indication of existence of transgressive segregation for sugar yield that can be exploited. The sugar yield was weak though significantly correlated with high brix and poor grain yield during both the seasons requiring extensive crossing to improve these traits simultaneously. Keeping in view mean performance, SCA effects and heterobeltiosis, the hybrids, ICSA 474 × SSV 84, ICSA 24001 × ICSR 93046 and ICSA 474 × SPV 422 were identified promising for rainy season and the hybrids ICSA 24001 × SPV 1411 and ICSA 511 × ICSV 93046 were identified for postrainy season.

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Abstract  

A rapid and sensitive substoichiometric radiochemical method has been developed for the comparative extraction and quantification of silver with potassium salts of ethyl, propyl, butyl, pentyl and benzyl xanthates from hydrochloric, nitric and sulfuric acid media into chloroform. The effect of 0.1–4M H+ ion concentration of the respective acid on the substoichiometric extraction of silver was critically studied. The efficiency of the method developed was tested by the determination of 10–100 g silver in standard solutions with an average percentage of error better than 2. The methods developed have been utilized to determine silver content in photofilm washing collected from various photostudios in Tirupati, India.

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Abstract  

A radiochemical displacement method has been developed for the determination of 10 g amounts of iron and antimony. The effect of pH and various foreign ions on the displacement of tracer60Co from labeled Co-o-Hydroxybenzaldehyde isonicotinoyl hydrazone (BIH) complex in isoamyl alcohol by iron and antimony was studied.

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A densitometric high-performance thin-layer chromatographic (HPTLC) method has been established for quantitative determination of sildenafil citrate in herbal medicinal formulations. Chromatography was performed on silica gel 60 F 254 HPTLC plates, prewashed with methanol, with toluene-acetone-methanol, 6 + 2 + 2 ( v/v ) as mobile phase. The plates were developed vertically, to a distance of 8 cm, in a saturated chamber, and densitometric quantitation was performed at λ = 312 nm by reflectance scanning. Recovery from the herbal medicinal powders and tablets was 83.17% and 99.41%, respectively. The standard sildenafil citrate calibration plot was linear ( r =0.9993) over the concentration range 100–600 ng per spot and the quantitative results showed the sildenafil content of the herbal formulations analyzed was in the range 76.4–85.0 mg | (RSD < 3%). This HPTLC technique is complementary to other chromatographic methods and has potential use for routine quality-control analysis.

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Abstract  

A simple and sensitive spectrophotometric method is developed for the determination of throium in aqueous medium. The metal ion forms yellow coloured complex with 2,4-dihydroxybenzaldehyde isonicotinoyl hydrazone (2,4-DHBINH) in the pH range 2.0–8.0. The complex shows an absorption maximum at 390 nm. The absorbance of the complex is maximum at pH 5.5 Beer's law is obeyed in the range 0.30–7.00 g/ml of thorium(IV). The molar absorptivity and the Sandell's sensitivity of the method are 2.20· 104 l·mol–1·cm–1 and 0.0106 g/cm–2, respectively. The interference of various ions was studied. The composition of the complex is 1:1 {Th(IV) : 2,4-DHBINH}. The first derivative spectrum of the complex shows a zero cross at 391.2 nm and maximum amplitude at 415 nm. Thus a sensitive derivative spectrophotometric method for the determination of Th(IV) is proposed.

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Abstract  

A substoichiometric radiochemical method has been developed for the determination of selenium with potassium ethyl xanthate. The selenium ethyl xanthate complex formed was extracted into chloroform from borate buffer at pH 5. The effect of foreign ions on the extraction was studied. Microgram quantities of selenium could be conveniently determined with a fair degree of accuracy. The method has been successfully applied for the determination of selenium content in food stuffs such as Jaggery and Wheat powder.

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Abstract  

A rapid and sensitive substoichiometric radiochemical procedure has been developed for the extraction of cobalt with potassium salts of ethyl, propyl, butyl, pentyl and benzyl xanthates. The relative extractabilities of the cobalt-xanthate complexes into chloroform and carbon tetrachloride were studied. Substoichiometric quantification methods were developed in each case and utilised to determine the cobalt content present in standard solutions as well as biological samples.

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