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.
Sixty durum wheat genotypes were analysed for protein (gliadin) polymorphism to find out the existing genetic diversity, and to assess its utility for improvement in grain yield along with quality traits. Six different
alleles were found in land races, rust resistance sources and old released varieties, while two in recently released and advance lines. Most of the recently released varieties and advance lines showed γ-45/
alleles, which is the best type for pasta making quality, remaining showed γ-42/
allele, which are not good for pasta making. It is advisable to select for γ-45/
as a bio-chemical marker in the future breeding programmes. The rust resistance sources do not possess γ-45/
alleles, so these lines can be used as donors to introduce disease resistance in the good quality recently released varieties, which are containing γ-45/
alleles. From hierarchical analysis, it was found that landraces, released varieties and rust resistance sources are genetically distinct. The presence of new γ-gliadin patterns are interesting in rust resistance sources and need to be investigated for their role in pasta making as well as overall technological quality of durum wheat.
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.
The present study deals with the ontogeny, structure and development of Cardiospermum halicacabum fruit and the mode of its dehiscence. The trigonous, pyriform and bladdery capsular fruit of C. halicacabum develops from a 3-celled ovary with one ovule in each cell. The ovary wall is 5 to 7 cell layers thick. The outer epidermis of the ovary wall develops into a single-layered epicarp. The isodiametric cells of developing epicarp contain abundant tanniniferous contents. The 3 or 4 layers thick ground parenchyma of ovary wall constitutes the mesocarp. The thin walled cells of developing mesocarp are found to get apart from each other, as their elongation is meagre, to keep pace with the increment in the circumference of fruit. The tangentially elongated cells of inner epidermis of ovary wall form a single layered endocarp. The endocarpic cells of developing fruit do not exhibit much structural changes, except vacuolation. Due to the disintegration of thin walled parenchyma cells situated throughout the length of the septum and rupture of similar type of cells located in between two lateral vascular bundles, the ripe capsule of C. halicacabum dehisces septicidally.
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.