VOLUME 13, NO1, MAR 1991

METHOD OF WASHING FILTER PAPERS TO REMOVE NITROGEN CONTAMINATION

Whatman filter papers contain inorganic nitrogen impurities (NH4, NO3 and NO2-N) which could introduce an error into the analysis of coal mine soils. The levels of inorganic nitrogen in the filter paper were found to be 3.1 to 5.3 mg of NH4-N and 12.1 mg of NO3-N/kg of filter paper. In order to minimise the effects of inorganic nitrogen contained in the filter papers, it is necessary to wash them with 0.5 M H2SO4, rinse them with deionised water and dry them prior to use for filtration.read more

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MUSHK I ALAM ,M Q KHAN ,S H SHAH ,

MEASUREMENT OF EXCESS THERMODYNAMIC FUNCTIONS FROM VISCOSITY DATA

Relative viscosities for formic, acetic, propionic and butyric acids in aqueous solutions were determined using thermostatic Ubbelohde flow viscometer in temperature range of 25 to 65-degrees-C. Excess viscosity, excess volume and activation parameter were calculated. It seems that as excess volume decreases with the rise of mole fraction of the particular acid and the corresponding excess viscosity increases. The effect of temperature on excess viscosity is much more telling than the same effect on DELTA-V(E). The explanation of this behaviour appears to be in the fact that with rise of temperature the intermolecular forces between acid-acid, acid-solvent and solvent-solvent change significantly to effect the viscosity behaviour, whereas for excess interactions as a function of temperature seems to get in different directions. This behaviour is well known for a liquid containing hydrogen bonds.read more

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ZULFIQAR ALI ,M AFZAL ,HABIB AHMAD ,

GLC AND HPLC STUDIES OF COPPER(II), NICKEL(II), PALLADIUM(II), AND VANADIUM(IV) COMPLEXES OF BIS(SALICYLALDEHYDE)TETRAMETHYLETHYLENEDIIMINE

The copper, nickel, palladium and vanadium complexes of tetradentate ligand bis(salicylaldehyde)tetramethylethylenediimine(H2SA2Ten) are prepared and their DTA and TGA are recorded. Nickel complex indicates reasonable volatility and thermal stability with loss in weight upto 98.7%, but copper, palladium and vanadium complexes leave significant residue behind with loss in weight in the range from room temperature to 500-degrees-C. The metal complexes elute on GLC column (6' x 0.085) packed with OV101, 3% on Chromosorb WHP 80-100 size with detection limits at sub-mu-g level of metal complexes and complete separation palladium from copper, nickel and vanadium complexes. The spectrophotometric studies of metal complexes indicate reasonable sensitivity within UV region and their adsorption HPLC column (250 x 4 mm) packed with Licrosorb Si100, 5-mu, connected with UV detector demonstrated complexes. The complexes were eluted isocratically with binary mixture of chloroform 1,2-di-chlorethane and detection limits were found at sub ng levels of metal complexes. The reagent has been applied for the determination of nickel in nickel-aluminium alloy using both GLC and adsorption HPLC. The result agree to each other and the expected value.read more

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M Y KHUHAWAR ,G Q KHASKHELI ,

EVALUATION OF A SUITABLE EXTRACTANT FOR THE EXTRACTION OF INORGANIC NITROGEN FROM COAL-MINE SOILS

Various Potassium salts (0.5 M K2SO4, 1 M KCl and M CH3 COOK) were tested for the extraction of inorganic nitrogen (NH4, NO3 & NO2-N) from coal mine soils. Although the amount of NH4-N extracted by various extractants was significantly different, there was no regular increase/decrease in the levels of NH4-N extracted by the various salt solutions. The amount of NO3-N extracted by KCl was significantly more compared to K2SO4 or CH3COOK which was attributed to the Cl ions interference in the colorimetric determination of NO3-N. The K2SO4 salt solution did not interfere and was, therefore, recommended to be used as an extractant for the colorimetric determination of soil inorganic nitrogen.read more

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MUSHK I ALAM ,M Q KHAN ,S H SHAH ,S H SHAH ,MUSHK I ALAM ,

USE OF INFRARED-SPECTROSCOPY FOR THE IDENTIFICATION OF URINARY-TRACT CALCULI

Various Potassium salts (0.5 M K2SO4, 1 M KCl and M CH3 COOK) were tested for the extraction of inorganic nitrogen (NH4, NO3 & NO2-N) from coal mine soils. Although the amount of NH4-N extracted by various extractants was significantly different, there was no regular increase/decrease in the levels of NH4-N extracted by the various salt solutions. The amount of NO3-N extracted by KCl was significantly more compared to K2SO4 or CH3COOK which was attributed to the Cl ions interference in the colorimetric determination of NO3-N. The K2SO4 salt solution did not interfere and was, therefore, recommended to be used as an extractant for the colorimetric determination of soil inorganic nitrogen.read more

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FATEH UDDIN KHAND ,AHMED FAROOQ ANSARI ,M Y KHUHAWAR ,SAIF ULLAH MEMON ,

NEGATIVE FIELD DESORPTION MASS-SPECTROMETRY OF NUCLEOTIDES

Negative ion field desorption mass spectrometry (NFD MS) has been applied to some nucleotides. Polyethylene glycol (PEG 4000) was used as a matrix to facilitate the ion formation at low field strengths and temperatures. Molecular ions of mononucleotides could be obtained with no or a low level of fragmentation. In contrast, NFD mass spectra of dinucleotides and a mononucleotide triphosphate did not exhibit molecular ions but only fragment ions.read more

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M SUBHAN ,F W ROELLGEN ,NOOR AHMAD ,

GAS-CHROMATOGRAPHIC STUDIES OF PALLADIUM(II) AND VANADIUM(IV) OXIDE COMPLEXES OF MESO-AND DL-BIS(ACETYLACETONE)STILBENEDIIMINE AND MESO-AND DL-BIS(TRIFLUOROACETYLACETONE)STILBENEDIIMINE

The palladium and vanadium(IV) oxide complexes of bis(acetylacetone)-meso-stilbenediimine (meso-H2AA2S), bis(acetylacetone)dl-stilbenediimine (dl-H2AA2S), bis(trifluoroacetylacetone)meso-stilbenediimine(meso-H2F2AA2S) and bis(trifluoroacetylacetone)dl-stilbenediimine(dl-H2F3AA2S) have been prepared, and their DTA and TGA indicate that the complexes are somewhat volatile. The complexes eluted from the stainless steel gas chromatographic column (2 m x 3 mm) and (3 m x 3 mm) packed with OV101, 3% on Chromosorb 80-100 mesh size and Dexil 400 GC, 2% on Uniport HP 60-80. The linear calibration ranges were within 0.5-20-mu-g and detection limits were within 10-250 ng of metal complexes at the optimized conditions of separation. The relative elution of the metal complexes on nonpolar column indicated that introduction of phenyl groups increases and trifluoromethyl group decreases on column retention of the metal complexes.read more

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M Y KHUHAWAR ,R B BOZDAR ,

COMPARATIVE-STUDY OF DIFFERENT METHODS FOR SULFIDE DETERMINATION WHEN ADOPTED TO FLOW SYSTEM

Different FIA procedures based on spectrophotometric determination of sulphide are described. For each method the effect of various parameters including, reagent concentrations, flow rate, pH mixing coil length, minicolumns and interfering species are investigated. Comparison of these methods with respect to detection limit, sampling rate and accuracy is made. Detection limits of 80 ppm, 1.0 ppm and 0.5 ppm with sampling rates 120, 30 and 44/hr, having the relative standard deviation 0.96, 1.8 and 0.4% respectively were observed for the three methods established.read more

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M YAQOOB ,L RISHI ,M MASOOM ,

A NOVEL SYNTHESIS OF NIDO-[8-HO-7-CB10H12]-ANION

A nido-closo-nido interconversion reaction of 7-Me3N-nido-7-CB10H12 is discussed. Nido-[8-HO-7-CB10H12]- anion is obtained from the reaction of 7-Me3H-nido-7-CB10H12 with sodium hydride. At ambient temperature the initial product is the deprotonated species, nido-[7-Me3N-7-CH10H11]-, but after reflux and hydrolysis the isolated product is the nido-[8-HO-7-CH10H12]- anion with the closo-[2-CB10H11]- as an intermediate. The results unambiguously show [OH] substitution at B (8) position.read more

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SHAH ALAM KHAN ,

INVESTIGATION OF SPECTROPHOTOMETRIC METHODS FOR DETERMINATION OF ORGANOPHOSPHORUS INSECTICIDES AND ITS APPLICATION TO FRUIT SAMPLES .2.

An indirect spectrophotometric method based on the complexation of copper with insecticides was investigated. The method was checked for its percent recovery of insecticides in various fruits like plums, apricots and grapes. The recovery of the method was found to be 94%. The method was also applied for malathion residue determination in selected fruits. Limit of detection of the method was investigated and was found to be 0.2-mu-g/ml.read more

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JASMIN SHAH ,M RASUL JAN ,