http://nopr.niscpr.res.in/handle/123456789/19937 2026-10-09T16:24:27Z 2026-10-09T16:24:27Z Pal, Anjali Maji, Sanjoy Kumar http://nopr.niscpr.res.in/handle/123456789/19993 2013-07-22T16:37:36Z 2006-05-01T00:00:00Z

Title: Spectrophotometric determination of arsenic via nanogold formation in micellar medium Authors: Pal, Anjali; Maji, Sanjoy Kumar Abstract: Colloidal gold nanoparticles are formed in aqueous anionic micellar medium by the qu antitative reduction of chloroauric acid (HAuCl₄) by arsine (AsH₃) gas produced from arsenic bearing sample water. The absorbance of the pink gold sol(λ_max at 530 nm) is a measure of arsenic concentration present in the sample .Both, As(III) and As(V) either present individually or in mixture could be determined. The molar absorptivity is 6.1×10³ lit mol^-1 cm^-1 and the Sandell sensitivity is 1.28×10^-2 μg cm^-2. The gold particles, as observed from the transmission electron microscopy analysis, are spherical in nature, the average size being 14±5 nm. The linear dynamic range (LDR) for the arsenic determination is 0-0.5 ppm (0-6 67×10^-6<i>M</i>)<i>. </i>The limit of detection (LOD) is 0.005 ppm. The 95% confidence limit for 0.2 ppm of arsenic is 0.207± 0.007 ppm (for 10 replicates). The relative standard deviation (RSD) is <±5%. The method is free from the common interferences, Fe²⁺/ Fe³⁺,Ca²⁺/Mg²⁺ PO₄^-3, SiO₃^-2 ,NO₃^-, Cl^-,SO₄^-2, humic acid, common herbicides/pesticides like 2, 4-D, endosulfan, atrazine, etc, and can be applied for the determination of total arsenic concentration in real water samples. The results are in good agreement with the SDDC method. The toxic and volatile organic solvents used for silver diethyldithiocarbamate method could be avoided in this method and hence it is safer, much easier and more reproducible. Page(s): 1178-1182

2006-05-01T00:00:00Z Sun, Wei You, Jiayu Wang, Qingxiang Jiao, Kui http://nopr.niscpr.res.in/handle/123456789/19992 2013-07-22T16:36:00Z 2006-05-01T00:00:00Z

Title: Voltammetric determination of DNA based on its interaction with neutral red Authors: Sun, Wei; You, Jiayu; Wang, Qingxiang; Jiao, Kui Abstract: A new linear sweep voltammetric (LSV) assay of fsDNA based on its interaction with neutral red (NR) is presented. At <i>p</i>H 8.0 Britton-Robinson (B-R) buffer solution, the dye can bind with DNA to form a supramolecular complex, which results in the decrease of the linear sweep voltammetric reductive peak current at -0.60 V (vs. SCE) on the mercury electrode. The binding reaction is completed within 20 min at room temperature and remains stable for at least 2 hours. The optimal conditions for the binding reaction and the electrochemical detection have been determined. Under the optimal conditions there is little interference from most metal ions and amino acids. The calibration graph for fsDNA is linear in the range of 1.0~30.0 mg/L with the linear regression equation as Δ<i>l</i>_pʹʹ(nA)=28.20C (mg/ L)+ 10.84 (n=9, γ=0.992) and the detection limit as 0.67 mg/L. The interaction mechanism is characterized by the aggregation of DNA-NR supramolecular complex by UV-vis absorption spectrophotometry and cyclic voltammetry. The stoichiometry of this supramolecular complex has been calculated with the binding number as 1.5 and the binding constant as 1.73×10⁷ Page(s): 1173-1177

2006-05-01T00:00:00Z Awasthy, Anubhuti Bhatnagar, Mamta Joshi, Nidhi Sharma, Uma http://nopr.niscpr.res.in/handle/123456789/19991 2013-07-22T16:36:29Z 2006-05-01T00:00:00Z

Title: Effect of side arm chain length of redox ionophores on uptake of some metal ions Authors: Awasthy, Anubhuti; Bhatnagar, Mamta; Joshi, Nidhi; Sharma, Uma Abstract: Synthesis of redox switched ionophores 1-[1-anthraquinonyloxy) 3, 6 dioxaoctane-8-methane (A₁) and 1-[1-anthraquinonyloxy] 3 oxapentane-5-methane (A₂) has been reported. These ionophores have been used as carriers in liquid membrane transport and extraction studies of alkali and alkaline earth metal ions. The sequence of metal ions extracted and transported in oxidised and reduced state by ionophore A₁ is: Ca²⁺>K⁺>Li⁺>Mg²⁺ and Li⁺>K⁺>Ca²⁺>Mg²⁺  respectively. The order of ex traction and transport of metal ions with respect to ionophore A₂is Li⁺>K⁺>Ca²⁺ and Ca²⁺>K⁺>Li⁺ respectively. Ionophore A₁ is selective for Ca²⁺ while ionophore A₂ is selective for Li⁺ions. This selectivity may be used in ion selective electrode and redox switch able devices. Page(s): 1170-1172

2006-05-01T00:00:00Z Bhat, J Ishwara Sreelatha, T N http://nopr.niscpr.res.in/handle/123456789/19990 2013-07-23T16:36:19Z 2006-05-01T00:00:00Z

Title: Effect of DMF on the solvation behaviour of BiCl₃in CH₃OH and CH₃CN: A conductometric study Authors: Bhat, J Ishwara; Sreelatha, T N Abstract: The effect of addition of dimethyl formamide on the conductivity and solvation behaviour of BiCl₃ in CH₃OH and CH₃CN at four different temperatures has been reported. In both the solvents, the conductivity is found to decrease and the solvation is found to increase on addition of DMF at all temperatures. Kraus-Bray and Shedlovsky conductivity models have been used to evaluate the limiting molar conductance, dissociation and association constants. Ion pair formation constant and triple Ion constant have also been computed. Walden product and thermodynamic parameters are also reported. Solvation number of the species of BiCl₃ has been calculated in pure solvents by the mobility method. Page(s): 1165-1169

2006-05-01T00:00:00Z