VOLUME 19, NO4, DEC 1997

A study of the structural features of metal impregnated charcoals by X-ray diffraction technique

Activated charcoal was impregnated with cobalt, nickel, copper and zinc. The impregnated charcoals have been studied employing x-ray diffraction technique. Various structural parameters including crystallite size, degree of amorphousness, radius of gyration and density have been calculated from the x-ray diffraction patterns. The results reveal that structural properties of charcoal change upon impregnation with metal ions.read more

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RIAZ QADEER ,MAHMOOD AHMAD ,RIZWAN HUSSAIN ,

Circular dichroism studies of complex forming ability of (+)-benzylpenicillin with VO(IV), Cr(III), Co(II) and Cu(II) ions in alcohol water (70 : 30) solution

Formation of complexes of antibiotic (+)-benzylpenicilline ((+)-(BP) with VO(IV), Cr(III), Co(II) ions in EtOH/MeOH:H2O (70:30) solution has been studied through circular dichroism. The optimum conditions of pH, stoichiometry and time for achieving maximum complexation in these systems are reported. Their formation constants are also determined. The CD spectra of these complex ions formed in solution are interpreted.read more

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ABDUL KHALIQUE ,CHISTY MUNIR ,NASIR AHMAD ,

Influence of water discharge on chemical assessment of water quality of river Indus at Kotri Barrage, Pakistan

The work monitors the quality of river Indus, its variation with seasonal discharge of water at Kotri Barrage during April 1993-1995. A sample was collected after every 4 to 6 weeks and was analyzed for residues (Total, filterable, non filterable, volatile and fixed), pH, conductance, chloride, hardness, alkalinity, dissolved oxygen (DO), chemical oxygen demand (COD) nitrite, nitrate, phosphate, sulphate, nitrogen (Kjeldalh, organic and ammonia) and phenols. The results obtained were compared with permissible limits for river water (EEC). The total average residues transported was calculated to be 12.14 x 10(7) tonnes/year, which accounts for 8.8 x 10(6) tonnes/year used for irrigation and 11.26 x 10(7) tonnes/year drain down to Arabian Sea.read more

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M Y KHUHAWAR ,V K DEWANI ,I A ANSARI ,

Kinetics spectrophotometric determination of silver(I) by the catalytic effect on the oxidation of chromotropic acid by bromate

A kinetic spectrophotometric method for the determination of silver has been described, based on its catalytic effect on the oxidation of chromotropic acid with bromate. The rate of change in absorbance with respect to blank is measured spectrophotometrically at pH 1.7. The effect of pH and concentration of bromate, chromotropic acid and silver on the rate of reaction were investigated. At the optimized conditions the proposed method allows the determination of silver in the range of 2-10 mu/ml. The effect of different ions on determination of silver was examined and the method was applied for the determination of silver in a photographic film.read more

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I A ANSARI ,M Y KHUHAWAR ,A A KHASKHELI ,G M MASTOI ,

Spectrophotometric determination of cobalt and iron in pharmaceutical preparation using 6-methyl-2-pyridinecarboxyaldehyde 4-phenyl-3-thiosemicarbazone as chromogenic reagent

The reaction of new spectrophotometric reagent 6-methyl-2-pyridinecarboxyldehyde-4-phenyl-3-thiosemicarbazone (MPAPT) towards copper(II), nickel(II), cobalt(II), cobalt(III) cadmium(II), iron(II), bismuth(III), lead(II), mercury(II), palladium(II), platinum(IV) manganese reactions are rapid at optimized pH within 1-11 in methanol-water with molar absorptivity in the range of 0.36-4.4x10(4) L-mole(-1) cm(-1). The complexes are extractable in chloroform as metal chelates compunds. The cobalt(II) develops colour even at hydrochloric acid (0.8 M) in methanol-water and colour of iron(II) changes from yellow to green at pH 9, which is extractable in chloroform. Cobalt in large excess of iron could be determined in a mixture. The reagent has been used for the determination for cobalt and iron separately and in a mixture in pharmaceutical preparations with relative standard deviation (RSD) within 0.5-21%. The results have been compared using atomic absorption spectrometer.read more

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M Y KHUHAWAR ,PRITAM DAS JAIPAL ,

Circular dichroism spectra of mononuclear complexes of Fe(II), Co(II) and Ni(II) with a chiral Schiff base R-1,2-propane bis(5-imino-1-phenyl-1,3-hexadione)

The CD and absorption spectra of mononuclear [Co(R-pn(BAA)(2))], [Ni(R-pn(BAA)(2))]. H2O and [Fe(R-pn(BAA)(2))] in three solvents i.e. Acentonitrile, chloroform and dioxane are reported. The CD of these complexes is influenced by the solvent. These studies indicate that metal ion in [Fe(R-pn(BAA)(2))] shifts from O-2-O-2 to N-2-O-2 compartment of the ligand in acetonitrile and dioxane solutions while in chloroform solution it is predominantly bonded to O-2-O-2 part. The CD bands of these complexes are interpreted in terms of electronic excitations to unidimensional levels. Further, Delta absolute configuration around the metal ions is assigned to these complexes.read more

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ROSHAN AHMAD ,SHEHNAZ IQBAL ,NASIR AHMAD ,

Study of aerial oxidation of sulphide contents in tannery wastes

Waste effluents from leather tanning industry contain a large quantities of sulphide salts which cause pollution in land and water channels and when come in contact with some acidic media, release a highly toxic gas hydrogen sulphide into air. Hence to protect the environment, it is desirable that sulphide content from tannery wastes should either be removed or converted to some harmless compound before leafing the waste into some water channel. In this work aerial oxidation of sulphide has been studied by designing model experiments in laboratory. Basically oxidation was carried out by bubbling air through sulphide solution and a number of concerned parameters like the role of catalyst, temperature and time have been studied. Real sulphide samples from tanneries were also successfully oxidized by employing optimum conditions.read more

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SYEDA FARHANA MAHMOOD ,JAMIL ANWAR ,WAHEED UZ ZAMAN ,

Thermodynamic study of the tetradentate keto-amine nickel(II) complexes as stationary phase for gas chromatography

Stability constant (k(m)), enthalpies (-Delta H), entropies (-Delta S) and Gibb's free energy (-Delta G) of gas chromatographic (GC) elution of alcohols, aldehydes, ketones, aromatic hydrocarbons, hetroaromatic compounds and analine from stainless steel column (3m x 3 mm id) packed with [1] OV101 3% [2] OV101 3% + bis(acetylacetone) ethylenediimine nickel(II) (AA(2)enNi) 5%, [3] OV101 3% + bis (acetylacetone) propylene diimine nickel(II) (AA(2)PnNi) 5% [4] OV101 3% + bis(acetylacetone) meso-stilbenediimine nickel(II) (meso-AA(2)S Ni) 5% on Chromosorb G/NAW 60-80 mesh size have been calculated. The donor-acceptor complexation in gas phase is indicated with negative values of enthalpy, entropy and Gibbs' free energy.read more

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M I BHANGER ,M Y KHUHAWAR ,ASHFAQUE A MEMON ,S A MEMON ,

Synthesis and analytical applications of hydroxamic acids for determination of vanadium(V)

A number of monohydroxamic acids like salicyl, cinnamo, m-nitro benzo, tartaric and benzohydroxamic acids as well as dihydroxamic acids were synthesized and characterized using spectroscopic techniques with the aim to develop selective chelating agents for determination of transition metals. Optimum conditions for maximum complexation and wavelength for spectrophotometric determination were investigated. lambda(max) of 308 +/- 2 was observed with all ligands investigated, while pH-2 and 11 were found optimum pHs for maximum complexation. Interferences effect of selected cations on determination of vanadium(V) and its detection limits were also investigated.read more

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MAHMOOD A KHAWAJA ,M RASUL JAN ,NAZIR JAN ,

Separation identification and determination of nicotinic acids and nicotinamide in cigarette tobacco and smoke (Part-I)

Nicotinic acid and Nicotinamide were separated, identified and determined in cigarette tobacco and smoke by reverse phase HPLC with UV detection using water methanol (1:1) as mobile phase. Optimum solvent, volume of solvent, temperature and time were investigated for the extraction of nicotinic acid and nicotinamide from tobacco. All available brands of cigarettes tobacco and cigarette smoke were analyzed at optimum conditions and the results are presented and discussed.read more

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M RASUL JAN ,JASMIN SHAH ,FAHMIDA GUL ,ABIDULLAH SHAH ,