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Abstract  

A new method for obtaining radiochemically pure67Cu from highly active fission product solutions is described. The method is based on the solvent extraction of the Cu(II)-diethyldithiocarbamate complex in n-butyl acetate in the presence of hold-back carriers for Ni, Co, Mn, Mo, rare earths, Cd, Te and Sb, and subsequent purification steps involving scavengings for Ag, Ba, Sr and Fe followed by an anion-exchange purification step for decontamination from Te. Copper is finally extracted as the α-benzoin oxime complex in which form it is mounted and counted. The method has several advantages over other methods in that decontamination is very high and it is sufficiently fast considering the stringent radiochemical purity achieved. The67Cu separated by this procedure from a one-day-old mixture of fission products arising from 1010 fissions was found to be completely free of any contamination.

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The dried fruits of Piper longum are extensively used in Ayurvedic medicinal preparations. A simple and convenient HPTLC method has been developed for standardization of the plant material using the two major constituents, pellitorine and dihydropiperlonguminine, as markers. The stationary phase was silica gel 60 F 254 , hexane-ethyl acetate, 75 + 25 ( v/v ), was used as mobile phase, and detection was at λ = 260 nm. The method is characterized by high sensitivity and linearity over a wide range of concentrations. The results obtained were evaluated statistically.

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Summary

Linear gradient HPLC on a C8 column has been used for separation of individual related substances of amoxicillin listed in the European Pharmacopoeia and a newly identified degradation impurity. The USP plate count for the amoxicillin peak was more than 3000 and USP tailing for the same peak was less than 2.0. Forced degradation studies were conducted on amoxicillin drug substance using ICH stress study guidelines to demonstrate the specificity and stability-indicating nature of the method. A new impurity observed after thermal and alkaline degradation was identified as N-pivaloylamoxicillin. The LOD and LOQ for individual related substances were below 0.045 and 0.086% (w/w), respectively. The method was fully validated in accordance with ICH analytical method validation guidelines. The results of the study prove the method is specific, precise, linear, robust, and can be used for evaluation of the stability of amoxicillin drug substance.

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Summary

Gymnemic acid (GA), a well known anti-diabetic compound has been detected in methanol extracts of intact leaves and in vitro callus cultures derived from leaf explants of Gymnema sylvestre. Callus biomass was developed in MS medium with optimum plant growth regulators (OPGRs) of 2,4-D (1.5 mg L−1) + KN (0.5 mg L−1) under abiotic stress conditions at 45 days determined by growth curve analysis. GA detection and quantification were carried out using thin-layer chromatography (TLC), highperformance thin-layer chromatography (HPTLC), high-performance liquid chromatography (HPLC), and gravimetric techniques. GA detection peak area and their absorption spectra were evaluated through HPTLC and HPLC with the standard GA. Quantification of GA had showed the linearity, accuracy, robustness and precision by HPLC. GA content was significantly higher in gravimetric method than HPLC. All these methods were found to be simple, accurate, selective and rapid and could be successfully applied for the determination of GA. It could have potential as a pharmaceutical drug for Type 1 diabetes mellitus (IDDM) and obesity.

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Abstract  

The potentiometric determination of uranium is widely carried out in phosphoric acid medium to suppress the interferences of plutonium by complexation. Owing to the complexity of the recycling plutonium from the phosphate based waste involving manifold stages of separation, a method has been proposed in the present paper which does not use phosphoric acid. Uranium and plutonium are reduced to U/IV/ and Pu/III/ in 1M H2SO4 by Ti/III/, and NaNO2 is chosen to selectively oxidize Pu/III/ and the excess of Ti/III/. The unreacted NaNO2 is destroyed by sulphamic acid and excess Fe/III/ is added following dilution. The equivalent amount of Fe/II/ thus liberated is titrated against standard K2Cr2O7. R.S.D. obtained for the determination of uranium /1–2 mg/ is 0.3% with plutonium being present upto 4.0 mg.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: S. Balasubrahmanyam, B. Viswanathan, V. Rao, and J. Kuriacose

Abstract  

The effect of60Co -radiation on La2CuO4 solid catalyst prepared by the ceramic method has been studied. Gamma irradiation of La2CuO4 samples has been found to increase the Cu+ content, electrical conductivities and decrease the magnetic susceptibilities of the catalyst. The results have been interpreted on the basis of the crystal field model of the structure of La2CuO4.

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Some studies on thallium oxalates — IV

Thermal decomposition of rubidiumbis-oxalato diaquo thallate(III) dihydrate

Journal of Thermal Analysis and Calorimetry
Authors: S. R. Sagi, Karri V. Ramana, and M. S. Prasada Rao

Thallium(III) was precipitated with oxalic acid in the presence of 0.025M RbNO3 (or 0.0125M Rb2SO4) in 0.1M HNO3 (or 0.05M H2SO4). Chemical analysis of the solid obtained corresponds to the formula Rb[TlIII(C2O4)2]·4 H2O. Thermal studies (TG, DTG and DTA) indicated the dehydration and redox decomposition of the thallic salt to the thallous salt, and finally to a mixture of rubidium carbonate and oxides of thallium(I) and thallium(III). Infrared absorption spectra, microscopic observations and X-ray diffraction data were used to characterize the original salt, as well as the intermediates formed during the thermal decomposition of the salt. On the basis of these results, the salt may be represented as: Rb[TlIII(C2O4)2(H2O)2]·2 H2O.

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A sensitive, selective, precise and stability-indicating high-performance thin-layer chromatographic (HPTLC) method for analysis of sertraline hydrochloride in the bulk drug and in formulations has been established and validated. Aluminum foil HPTLC plates precoated with silica gel 60F254 as stationary phase were used with toluene-ethyl acetate-ethanol-ammonia 8:2:0.5:0.1 (ν/ν). A compact spot was obtained for sertraline hydrochloride (R F 0.33 ± 0.02). Densitometric analysis was performed in absorbance mode at 273 nm. Regression analysis of calibration data revealed a good linear relationship (r 2 = 0.9996 ± 0.02) between response and concentration over the range 2000–12000 ng per band. The method was validated for accuracy, precision, linearity, limits of detection and quantification, and robustness. Sertraline hydrochloride was subjected to acidic and alkaline hydrolysis, oxidation, dry heat treatment, and photodegradation. Peaks of degradation products were well resolved from that of the pure drug and had significantly different R F values. Statistical analysis showed the method enabled repeatable and selective analysis of sertraline hydrochloride. The method can be used for routine quantitative analysis of sertraline hydrochloride in the bulk drug and in formulations.

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Abstract  

An improved method for the determination of plutonium in an aliquot using cerium/IV/ as an oxidant is reported. Plutonium is oxidized quantitatively to plutonium/VI/ in nitric acid medium by cerium/IV/, the excess of which is chemically destroyed in a single step by hydrochloric acid. Plutonium/VI/ is then reduced to plutonium/IV/ with a known amount of Fe/II/, the excess of which is back titrated potentiometrically with standard dichromate. Results of analysis of 3–5 mg amounts of plutonium in aliquots containing standard plutonium nitrate solution are reliable within 0.2%. Effect of the presence of some relevant foreign ions has been studied. The application of the method for the analysis of mixtures containing various amounts of uranium and plutonium has been examined.

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Ten dicoccum wheats were analyzed for their physico-biochemical and milling properties to evaluate the pasta making potential. Dicoccums showed higher protein content and mixograph midline peak values compared to durum variety MACS2846. Mixographic properties of dicoccums were poor compared to durums, due to lower functional visco elastic gluten content. Dicoccums were poorer in milling properties compared to durums, due to lower test weight and thousand-grain weight. Among dicoccums, DDK 1025 showed high micro SDS sedimentation volume and strong mixographic properties, but values were still lesser compared to durum MACS 2846. HMW glutenin subunits in recently developed/released dicoccums were similar to durum parents and were different from the older dicoccums. LMW glutenin subunits, however, were similar to dicoccum parents, except in DDK 1025 which showed LMW glutenin subunits similar to durum wheat. To breed high quality dicoccum wheat for pasta products, breeders should select superior glutenin subunits composition, along with better mixograph properties, keeping morpho-botanical characteristics of dicoccum wheat.

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