Hydrogen sulphide at trace level can be determined by radiorelease technique using radiochloramine-T. The minimum detection level is 0.25 ppm. Zinc acetate is used to fix H2S from air samples. CS2 does not interfere. Interference by SO2 can be eliminated by oxidizing it with H2O2.
Carbon disulphide can be determined at ppm level by converting it into xanthate and then oxidizing it by radiochloramine-T in acid medium. Interference of sulphide, sulphite and nitrite can be eliminated by extracting CS2 from the mixture into carbon tetrachloride and stripping it into aqueous medium as xanthate by the addition of alcoholic KOH to the organic layer.
Authors:I. Pius, Aruna Kadam, M. Rao, V. Rao, and P. Natarajan
Results of experiments on the adsorption of plutonium (IV) on alumina and their application to the recovery of plutonium from analytical waste solutions containing phosphoric-nitric acid are reported. Distribution ratios of plutonium (IV) between alumina and solutions containing varying concentrations of phosphoric acid and nitric acid are determined. The influence of various ions like UO22+, Fe3+, MoO42–, VO2+ and SO42– on the distribution ratio is evaluated. Saturation values of adsorption of plutonium (IV) on alumina and optimum conditions for loading and elution of plutonium on a column packed with alumina are described.
The spiny capsule of Argemone mexicanadevelops from a unilocular ovary with numerous ovules borne on pariteal placentae. The ovary wall comprises a layer of outer epidermis and inner epidermis each with 12 to 14 layered ground parenchyma or mesoderm in between. The epicarp, which develops from the outer epidermis of the developing pericarp, possesses numerous anomocytic type of stomata, but no trichomes. The deep lyind mesodermal layers from the mesocarp, which embed pericarpic vascular bundles and their tangentially extended ramifications. The thin walled and highly vacuolated mesocarpic cells undergo disorganisation at the maturity of fruit. The tangentially elongated cells of inner epidermis of ovary from the endocarp, which at maturity of the fruit possesses thick walled cells. The cells of placentum of developing fruit contain abundant starch. Due to the contraction of disorganised parenchyma cells, the dried fruit, leaving the marginal veins and persistent stigma, dechisces at its apical region.
Authors:Yeshwant Naik, G. Rama Rao, and V. Venugopal
The separation characteristics of hydrogen-tritium mixtures by gas chromatography at 77 K have been studied using molecular sieve 4A, coated with 5 wt% vanadium in the form of V2O4, as supporting material. The performance of the column was found to be better than that observed on the conventional coated and uncoated molecular sieves in terms of reduced retention times, resolution, nature of the peak and added thermal stability of the stationary phase.
Synergism is observed in the extraction of uranium(VI) by the binary mixture of Aliquat 336 and PC 88A (2-ethylhexylphosphonic acid mono-2-ethylhexyl ester) from 0.5–6M HNO3 solution showing a maximum at 3M. In H2SO4 medium, antagonism at lower acidity and slight synergism at higher acid concentrations have been observed. Synergism occurs in the extraction of Am(III) from nitrate solutions when a mixture of Aliquat 336 and TOPO is used.
The exchange between bromamine-T and radioactive bromide has been carried out in various media. The exchange is maximum at pH=2 and decreases in strong as well as weak acid media. No exchange occurs in alkaline medium. The optimum conditions for the preparation of radiobromamine-T with high specific activity are reported.