http://nopr.niscpr.res.in/handle/123456789/19936 2026-10-09T03:22:53Z http://nopr.niscpr.res.in/handle/123456789/19980 Title: Atomic absorption spectrometric determination of copper after adsorption of its sodiumdiethyldithiocarbamate complex on a new polymeric adsorbent Authors: Atamjyot; Jain, Preeti; Puri, B K Abstract: An atomic absorption spectrometric method for the determination of trace amounts of copper in various synthetic samples after adsorption of its sodiumdiethyldithiocarbamate complex on a new polymeric adsorbent has been developed. The copper complex is quantitatively adsorbed on the polymeric adsorbent in the <i>p</i>H range of 2.9-9.0. After filtration, the copper complex is eluted with 10 mL of dimethyl formamide and the metal is determined by atomic absorption spectroscopy. Beer's law is obeyed in the concentration range 0.15-2.0 ppm of copper in the final DMF solution with a correlation factor of 0.9989. Ten replicates of 2 ppm of Cu give a mean absorbance of 0.209 with a relative standard deviation of 1.6%. Various experimental conditions such as effect of <i>p</i>H on complexation/adsorption retention, volume of buffer solution, amount of reagent, amount of adsorbent, standing time, flow rate, volume of aqueous phase, choice of organic solvent have been optimized. Page(s): 409-411 2006-02-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/19979 Title: Solvent extraction separation of thorium(IV) from nitric acid with Cyanex 272 Authors: Karve, Manjusha; Belwalkar, Smruti; Rajgor, Reeta Abstract: Thorium(IV) has been quantitatively extracted from 1×10^-3 <i>M </i>nitric acid with 1×10^-3 <i>M </i>Cyan ex 272 in xylene. It has been<i> </i>stripped from the organic phase with 4 <i>M </i>hydrochloric acid and<i> </i>determined spectrophotometrically as its complex with Arsenazo(III) at 655 nm. The method developed has been applied for<i> </i>the separation of thorium(IV) from chromium(VI), vanadium(V), hafnium(IV), zirconium(IV), titanium(IV), iron(III), cobalt (II),<i> </i>calcium(II) and some rare earth elements. The applicability of the method has been checked for separation of thorium(IV) from<i> </i>associated elements in the synthetic mixtures and monazite sand.The method is simple, rapid and selective for thorium(IV) with a relative standard deviation of 0.27%. Page(s): 406-408 2006-02-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/19978 Title: Differential pulse polarographic determination of tetramethylthiuram disulphide Authors: Verma, B C; Kumar, Satish; Chauhan, Chetan; Sharma, D K Abstract: A differential pulse polarographic method for the determination of tetramethylthiuram disulphide (TMTD) by making use of its reaction with copper(I) perchlorate in acetonitrile has been developed. TMTD reacts with copper(I) perchlorate (1:1 molar ratio) and exhibits a well-defined, diffusion-controlled peak at - 120 mV showing five times more sensitivity than the one obtained due to TMTD alone. The linear relationship between concentration of TMTD and current intensity of peak at - 120 m V can be successfully adapted to the analysis of some fungicide and rubber accelerator formulations based on TMTD. Page(s): 402-405 2006-02-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/19977 Title: Kinetics and mechanism of oxidation of arsenous acid by Waugh-type enneamolybdomanganate(IV) Authors: Bhosale, B D; Gokavi, G S Abstract: The reaction between As(III) and Waugh-type enneamolybdomanganate(IV) has been studied in perchloric acid medium. The reaction follows a second order kinetics with an order of unity each on both the reactants and proceeds with a complimentary two-electron outer-sphere path. The reaction is accelerated by [H⁺] ions due to protonation equilibria of the oxidant. The first two protonation constants of the enneamolybdomanganate(IV) anion have been determined by <i>p</i>H metric titration and found to be 2.0 × 10³ and 316 dm3 Mol^-1. The product of reaction, enneamolybdomanganous(II) has been synthesized to study the effect of the added product. Both ammonium salts of enneamolybdomanganate(IV) and enneamolybdomanganous(II) have been characterized by FTIR and AAS. The reaction is unaffected by change in ionic strength and the free radical test is negative which suggests direct two-electron transfer from As(III) to oxidant. Di-protonated form of enneamolybdomanganate(IV) has been found to be active oxidant species. The solvent polarity and the thermodynamic parameters suggest the outer sphere mechanism. Page(s): 398-401 2006-02-01T00:00:00Z