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.
The stability constants of the complex of Pu/III/ with a humic acid at pH 2.9 and 5.0 were measured using solvent-extraction technique. The organic extractant was dinonyl naphthalene sulphonic acid in sodium form /NaD/ in benzene while the humate aqueous phase had a constant ionic strength of 0.5M /NaClO4/. The total carboxylate capacity of the humic acid was determined by direct potentiometric titration to be 6.201 Meq g–1. The apparent pKa increased as the degree of ionization // increased. The 1g
1 values of the complex of Pu/III/ with humic acid have been determined to be 2.8 and 3.11 at pH 2.9 and 5.0, respectively.
Chemisorbed oxygen can be determined quantitatively by the measurement of gaseous N2/N2O liberated by treatment with hydrazine sulphate/hydroxylamine hydrochloride. The amount of chemisorbed oxygen depends on the degree of dispersion during irradiation and also the -dose. The chemisorption is enhanced in the presence of moisture. The partial reduction of the transition metal ion favours the formation of chemisorbed oxygen.
Aqueous chloramine-B /C6H5SO2NCl Na/ solution is known to contain species like RNCl–, RNHCl, RNCl2, RN+H2Cl, HOCl and H2+OCl where R=C6H5SO2. The exchange studies between36Cl and CAB carried out in various media by ion-exchange method indicated that there is no exchange in solution at pH7. As the pH is decreased below 7, the extent of exchange increases reaching a maximum at pH 3. 3. The exchange decreases as the acidity is increased between pH 3.3 and 1N and again the exchange increases beyong 1N. The observed increase in exchange in strong acid medium is due to the evolution of chlorine.
The exchange between chloramine-B and radioactive chlorine has been carried out in various media. The exchange is slow in strong acid and very weak acid media. Its maximum is at pH 3.3. There is no exchange in alkaline media. Optimum conditions for the preparation of radiochloramine-B with high specific activity are reported.
A new method for the continuous determination of H2O2 is described based on the catalytic decomposition of H2O2 by LaCoO3. Oxygen liberated is measured by a gas meauuring burette. -irradiated catalyst enhances the catalytic activity and decreases the time required for complete decomposition. The procedure is suitable for microdetermination of H2O2 in various food products.
Exchange studies with36Cl and Chloramine-B in strong acid medium revealed that the extent of exchange is less than that occurs at pH 3.3 indicating the formation of a new species of Chloramine-B which is not participating in the exchange reaction and this has been confirmed by conductometric titration of Chloramine-B with dilute solutions of H2SO4, HCl, HClO4 and CH3COOH.
Studies on the individual potentiometric determination of uranium and plutonium in a single aliquot have been initiated recently
in our laboratory. It was required to adapt the reported procedures (for the precise determination of uranium and plutonium
individually when present together in a sample) at various stages to make them suitable for the successive application of
the procedures to the same aliquot. Two alternative schemes are proposed in the present work. In the first, plutonium is determined
by HClO4 oxidation followed by the determination of total uranium and plutonium by Zn(Hg) reduction. In the second, plutonium is determined
by AgO oxidation following the determination of total uranium and plutonium by Zn(Hg) reduction. Amount of uranium is computed
in both cases from the difference of two determinations. Precision for the assay of plutonium and uranium was found to be
±0.25% and ±0.35%, respectively, at milligram levels.