http://nopr.niscair.res.in/handle/123456789/959 Search the Channel search http://nopr.niscair.res.in/simple-search http://nopr.niscair.res.in/handle/123456789/1086 Title: Complexometric determination of mercury(II) using 2-thiobarbituric acid as a releasing agent <br/> <br/>Authors: Karthikeyan, J; Parameshwara, P; Shetty, A Nityananda; Shetty, Prakash <br/> <br/>Abstract: A simple and selective complexometric method for the deter-mination of mercury is proposed, based on the selective releasing ability of 2-thiobarbituric acid towards mercury(II). Mercury(II) present in a given sample solution is first complexed with an ex-cess of EDTA and the unreacted EDTA is titrated against zinc sulphate solution at pH 5-6 (hexamine buffer) using xylenol orange as the indicator. An excess of a 0.25% solution of 2-thiobarbituric acid is then added to displace EDTA from the Hg(II)-EDTA complex. The released EDTA is estimated. Repro-ducible and accurate results are obtained for 3-95 mg of mer-cury(II) with coefficient of variation not more than 0.34%. The effects of various ions were studied. The method is used for the analysis of mercury in its synthetic alloy mixtures and also in complexes. <br/> <br/>Page(s): 209-211 Mon, 26 Feb 2007 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/1085 Title: Solid phase extraction and estimation of cadmium using glycine immobilized cellulose chelating resin <br/> <br/>Authors: Singh, Parul; Mittal, S; Sharma, R K <br/> <br/>Abstract: A simple and rapid method of preconcentration and determination of cadmium by both batch and column techniques using glycine immobilized cellulose is presented. Cadmium ion is quantitatively retained on the column packed with immobilized cellulose in the pH range of 6.6-7.8. The distribution coefficient for cadmium is found to be 2.32x10² mL g⁻¹. The method is successfully applied to the determination of cadmium content in water and cigarette samples. <br/> <br/>Page(s): 204-208 Mon, 26 Feb 2007 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/1084 Title: Titrimetric and spectrophotometric determination of zidovudine in pharmaceuticals using chloramine-T and two dyes <br/> <br/>Authors: Basavaiah, K; kumar, U R Anil <br/> <br/>Abstract: Three new methods using titrimetry and spectrophotometry are described for the assay of zidovudine (ZDV) in bulk drug and in dosage forms using chloramine-T (CAT) and two dyes, methyl orange and indigocarmine, as reagents. Titrimetry involves treating of ZDV with a measured excess of CAT in hydrochloric acid medium, and after the oxidation of ZDV is seemed to be complete, the unreacted oxidant is determined iodometrically. Spectrophotometric methods entail the addition of a known excess of CAT to ZDV in hydrochloric acid medium followed by determination of residual oxidant by reacting with a fixed amount of either methyl orange and measuring the absorbance at 520 nm (Method A) or indigo carmine and measuring the absorbance at 610 nm (Method B). In all the methods, the amount of CAT reacted corresponds to the amount of ZDV. In titrimetric method, the reaction follows a reaction stoichiometry of 1:1 (ZDV: CAT), and is applicable over a range 3-10 mg of ZDV. In spectrophotometric methods, the absorbance is found to increase linearly with concentration of ZDV. The systems obey Beer’s law for 0.5-5.0 and 2.5-20.0 μg mL⁻¹ for method A and method B, respectively. The apparent molar absorptivities are calculated to be 3.4x10⁴ and 7.4x10³ L mol⁻¹ cm⁻¹for method A and method B, respectively. The methods were successfully applied to the assay of ZDV in tablet and capsule formulations. <br/> <br/>Page(s): 200-203 Mon, 26 Feb 2007 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/1083 Title: Concentration control of silica in water chemical regime for natural circulation high pressure drum boiler unit of thermal power station <br/> <br/>Authors: Sohail, M Azad; Mustafa, A Ismail <br/> <br/>Abstract: The effective relations of silica (SiO₂) concentration in boiler drum and generated steam, with respect to pH and pressure for a natural circulation water wall tubes (WWTs) high-pressure (158 and 100 kGք cm⁻²) boiler, (Type TGME-206-COB, Russia) at Ghorasal Thermal Power Station (GTPS) Bangladesh, has been studied. Extensive analyses of different parameters of boiler water chemical regime (WCR) of the plant based experimental results revealed that on maintaining SiO₂ 0.35 (± 0.15) mgL⁻¹ in boiler drum clean (evaporation) section [at pH 9.1 (± 0.1), temperature 330ºC (± 10ºC)] of boiler WCR provides excellent results with less corrosion or scale formation in interior surface of boiler WWTs and turbine blades. Such a procedure is effective for high softening of make up water SiO₂ 0.02 (± 0.01 mgL⁻¹) ensuring high degree of purity of feed water cycle of the boiler and appropriate dosing of chemicals in boiler. <br/> <br/>Page(s): 195-199 Mon, 26 Feb 2007 22:58:59 GMT