VOLUME 20, NO4, DEC 1998

Determination of sulphide in sediments and sewerage water by indirect conductometry

A conductometric method has been developed for the determination of sulphide in sediments and sewerage water samples. The method is based on the separation of sulphide as hydrogen sulphide by treating the sample with sulphuric acid The produced hydrogen sulphide was swept to an absorption solution of copper sulphate with the help of a nitrogen stream The increase in the conductivity of absorption solution was measured and plotted against sulphide concentration to obtain the calibration The effects of concerned parameters were checked and the method was applied to the real samples of sewerage water and sediments.read more

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ALIYA HAMEED ,WAHEED UZ ZAMAN ,FARHAT YASMEEN ,JAMIL ANWAR ,

High performance liquid chromatographic analysis of rutin in some Turkish plants II

The determination of ruin in Cydonia oblonga, Ecballium elaterium, Fraxinus angustifolia, Jasminum fruticans, Marsdenia erecta, Mimosa pudica, Nicotiana tabacum, Paliurus spina-christi and Ruta montana was carried out by using a sensitive reversed-phase high performance liquid chromatographic method Chromatographic analysis war achieved on I LiChrospher 100 RP18 5 mu m column by using an isocratic mixture of water, methanol and glacial acetic acid (65:30:5) at a flow rate of 0.8 ml/min as a mobile phase. The UV detection was performed at 259 nm. read more

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G TOKER ,N ERDEMOGLU ,S TURKOZ ,

"Adsorption studies of transition metals manganese to zinc over zirconyl silicate resin"

The anion exchange behaviour of first row transition elements Manganese to Zinc has been studied over Zirconyl Silicate in hydrochloric acid (0.3-3.0M) as eluent The adsorption of these elements changes sufficiently as a function of hydrochloric acid concentration to permit their separation The adsorption and stability of negatively charged complexes is found to be in the order of Ni(II) < Mn (II) < Cu (II) < Cr (III) < (Co (II) < Zn (II) < Fe (II). Unlike other elements studied, adsorption of Ni(II) is very small which decreases as the concentration of hydrochloric acid is increased. read more

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M L MIRZA ,ARSHAD MAHMOOD ,S A TIRMIZI ,JAVED IQBAL ,

Selected trace metal concentration in seven fish species from the Arabian Sea, Pakistan

Levels of eleven trace metals in edible muscle of seven commercial fish species harvested from the south west coast of the Arabian Sea, Pakistan are reported The maximum concentration was found in case of Zn (3.412 mu g/g) and Fe (3.591 mu g/g). Maximum As (0.273 mu g/g) was found in Argyrops spinifer and As (0.041 mu g/g) in Chaetodon jayakeri. The metal concentrations showed a high species-specificity. read more

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M ASHRAF ,M JAFFAR ,JALEEL TARIQ ,KHALID MASUD ,

Comparison of extractants for toxic metals in dust causing environmental pollution and their analysis in close and open system

The aim of this work was to look for an ideal extractant for toxic metals in dust. Twelve extractants were tested in close and open systems. Atomic absorption spectrophotometer was used to determine the concentrations of cadmium, chromium copper, cobalt lead nickel and zinc. Excess of all these are toxic to living organisms and are regarded as pollutants. Nitric acid 2M was found to be the best extractant. read more

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D A TANISLEY ,M H Z CHOUDHARY ,

A rapid differential method for simultaneous spectrophotometric determination of nickel(II) and cobalt(II) by a novel organic reagent N-(2-thienylmethylene)phenyl hydrazine

A novel organic reagent N-(2-thienylmethylene) phenyl hydrazine is synthesised and used as a useful chromogenic reagent for rapid simultaneous determination of nickel(II) and cobalt(II) by differential spectrophotometry. This method allows the determination of 0.2-1.23 ppm of nickel(II) and 0.25-1.5 ppm of cobalt(II) in mixtures with good precision and accuracy. It has advantages of simplicity, less time consumption and no prior separations etc. read more

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SYED K A SHERAZI ,ZAHID H CHOHAN ,

Use of malathion for high performance liquid chromatographic determinations of bismuth(III), copper(II) and palladium(II), based on complexation with dimethyl dithiophosphate

Malathion in alkaline solution is hydrolysed to dimethyldithiophosphate (DDTP), which is used as a complexing reagent for the HPLC separation and quantitative determination of bismuth(III), copper (II) and palladium (II) in a mixture. The complexes extracted in chloroform are eluted from normal phase HPLC column (250 x 4 mm id) Licrosorb, Si, 100, 5 mu with chloroform:acetonitrile:1,2-dichloroethae (25:70:5 v/v/v) with a flow rate 0.8 ml/min. The detection was at 295 nm Linear calibration for each of bismuth(III), copper(II) and palladium(II) were obtained with 12.5-62.5 mu g/ml of chloroform and detection limits were 0.1-0.2 ng/injection. The method was applied for the determination of copper in copper wires and palladium in plalladium-barium sulphate. read more

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A H CHANNAR ,S N LANJWANI ,M Y KHUHAWAR ,

Spectrophotometric determination of isoniazid using 6-methyl-2-pyridine carboxaldehyde as a derivatizing reagent

6-Methyl-2-pyridinecarboxyldehyde (MPA) reacts with isoniazid to form hydrazone derivative. The concentration of MPA pH and warming time for the determination of isoniazid were optimized The absorbance was measured at 328 nm against reagent blank Beer's law was obeyed in the range of 1.46.8 mu g/mL isoniazid The method was used for the determination of isoniazid contents in pharmaceutical preparations individually and in the presence of ethambutol and rifampicin. The results were obtained with coefficient of variation (C.V) within 0.7-3.8%. read more

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M Y KHUHAWAR ,K F ALMANI ,K F ALMANI ,F M A RIND ,K F ALMANI ,F M A RIND ,F M A RIND ,

Separation and speciation of organophosphorus pesticides based on hydrolysis using reverse phase HPLC

A new method for separation and speciation of organophosphorus pesticides have been investigated using reverse phase HPLC. Pesticides are hydrolysed by the addition of sodium ethoxide, the organic layer is separated from the aqueous phase which contain the acidic hydrolysed portion of the respective pesticides. Different pesticides give different acidic products on hydrolysis leading to variation in the retention time. The hydrolysed products are injected and separated on reverse phase HPLC. Identification and quantification is done by running the respective standards. read more

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M RASUL JAN ,KAHKESHAN SAEED ,JASMIN SHAH ,KAHKESHAN SAEED ,M RASUL JAN ,

Zero point charge and surface stability constants for Co2+ adsorption from aqueous solutions on kaolin

Surface charge of kaolin was estimated from the potentiometric titrations of kaolin in various background electrolyte solutions at 298 IC No point of intersection for the zero charge was observed at pH 3.5 as the starting point indicating that at low pH, the amorphous components of kaolin were adsorbed in the aqueous phase whereas the three various electrolyte solutions initially adjusted to about pH 8.48 gave the point of intersection The pH(PZC) was 5.96. The surface stability constants were measured in the temperature range (298 - 328 K) at pH 6.5. As the reaction was exothermic, like X-m, the maximum adsorption the values of the stability constants also decreased with increasing temperature showing high strength of bond between the adsorbent and adsorbate at low temperatures. read more

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SHAKILA BEGUM ,FARID ULLAH KHAN ,