Asian Journal of Research in Chemistry

S. Raju ¹, B. Ananda Kumar ¹, K. B. K. Naik ¹, G. Nageswara Rao ¹

Affiliations
1 Department of Inorganic and Analytical Chemistry, School of Chemistry, Andhra University, Visakhapatnam, Pin Code:530 003, IN

Abstract

Chemical speciation of ternary complexes of Co(II), Ni(II) and Cu(II) with L-histidine and L-glutamic acid was studied in various concentrations (0-60% v/v) of DMSO-water mixtures maintaining an ionic strength of 0.16 mol L^-1 (NaCl) at 303.0 K. Alkalimetric titrations were carried out in different relative concentrations (M: L: X = 1:2.5:2.5, 1:2.5:5.0, 1:5.0:2.5) of metal (M) to histidine (L) to glutamic acid (X) with sodium hydroxide as titrant. Stability constants of ternary complexes were calculated and various models were refined with MINIQUAD75. The trend of the variation in the stability constants with changing dielectric constant of the medium was explained based on the electrostatic interactions of the side chains of the ligands, charge neutralization, chelate effect, stacking interactions and hydrogen bonding. The species detected are MLXH, MLX₂H and MLX₂ for Ni(II) and Cu(II) and MLX₂H and MLX₂ for Co(II). Distribution diagrams with pH at different compositions of DMSO and structures of plausible ternary complexes were also presented.

Keywords

Ternary Complexes, Chemical Speciation, Stability Constants, DMSO, Essential Metals.

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G. Srinivas Rao ¹, G. Nageswara Rao ²

Affiliations
1 Department of Chemistry, GITAM Institute of Science, GITAM University, Visakhapatnam – 530 045, A.P., IN
2 School of Chemistry, Andhra University, Visakhapatnam – 530 003, IN

Abstract

Fifty sampling stations have been identified and water samples were collected from June 2006 to May 2007, to know the Water Quality Index for the groundwater of Greater Visakhapatnam city, The samples were analyzed for the physico-chemical parameters like Temperature, pH, Conductivity, Total dissolved solids, Dissolved Oxygen, Hardness, Calcium, Magnesium, Alkalinity, Chloride and Nitrate. The Water Quality Index has been calculated and it has been identified to be in the range 31 to 306. Salt water intrusion has also been assessed using various parameters.

Keywords

Ground Water, Water Quality Parameters, Water Quality Index, Salt Water Intrusion.

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G. Srinivas Rao ¹, G. Nageswara Rao ²

Affiliations
1 Department of Chemistry, GITAM Institute of Science, GITAM University, Visakhapatnam – 530 045, IN
2 School of Chemistry, Andhra University, Visakhapatnam – 530 003, IN

Abstract

Water samples were collected from 14 open wells, 34 bore wells and two reservoirs to study the ground water quality of Greater Visakhapatnam city. The samples were analyzed for the parameters like Temperature, pH, Conductivity, Total dissolved solids, Dissolved Oxygen, Hardness, Calcium, Magnesium, Nitrate, Sodium, Potassium, Chloride and Alkalinity. Low ionic concentrations in ground waters far (7-14 km distance) from the sea coast were observed which are within the permissible limits of WHO and ISI standards. Ground waters close to the sea coast i.e. one to two kilometers distance (60 to 150 feet depth) have high values of Conductivity, Total dissolved solids, Hardness, Chloride, Calcium, Magnesium, Sodium and Potassium which are not in permissible limits.

Keywords

Ground Water Quality, Visakhapatnam, Salt Water.

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R. Narendra Kumar ¹, G. Nageswara Rao ¹, P. Y. Naidu ¹

Affiliations
1 School of Chemistry, Andhra University, Visakhapatnam, IN

Abstract

A Fast LC method has been developed and subsequently validated for the determination of Cefditoren pivoxil and its related impurities in bulk and pharmaceutical formulation. Separation was achieved in Gradient mode using Hypersil BDS, C18, 100 x 4.6 mm, 3μm column with mobile phase A containing Ammonium formate buffer (pH adjusted to 6.0±0.05 with formic acid solution) and mobile phase B containing Methanol and Acetonitrile (40:60 v/v) at different time intervals as eluent at a flow rate 1.2ml/min. UV detection was performed at 230nm. The method is simple, rapid, and selective and stability indicating. The described method is linear over a range of 200.34μg/mL to 1520.56μg/mL. The method precision for the determination of assay was below 2.0% RSD .The Percentage recoveries of Active Pharmaceutical Ingredient (API) from dosage form is 99.2. LOD and LOQ of all related impurities of Cefditoren pivoxil was established and ranged from 0.0431μg/ml - 0.1843μg/ml for LOD and 0.1292μg/ml - 0.6014μg/ml for LOQ. The method is useful in the quality control of bulk manufacturing and also in pharmaceutical formulations.

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R. Narendra Kumar , G. Nageswara Rao , P. Y. Naidu

Abstract

An isocratic stability indicating liquid chromatographic method has been developed and validated for the determination of Eszopiclone in bulk drug and its pharmaceutical dosage form. Separation of the drug with degradation products was achieved using Peerless HT, C8, 50×4.6 mm; 1.8 μm column as stationary phase and pH 4.5(±0.05) buffer:Acetonitrile:Tetrahydrofuran (81:18:1, v/v) as mobile phase at a flow rate of 1.0 mL/min. UV detection was performed at 304 nm. The method is linear over the range of 10-150 μg/mL. The percent recovery of drug in dosage forms was ranged from 97.7 to 100.5. The method is simple, rapid, precise, selective and stability indicating and can be used for the assay in quality control and stability studies samples.

Keywords

Bird Flu, Chemsketch, Docking, Hex, Rasmol.

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