VOLUME 18, NO3, SEPT 1996

Temperature programmed desorption (TPD) of CO from alkali doped EUROPT-1 (6.3% Pt/SiO2)

The temperature programmed desorption technique was applied to investigate the changed characteristics of Pt/SiO2 (EUROPT-1) upon alkali doping. CO desorption peak maxima shifted towards higher temperature as the concentration of alkali increased. This indicated strengthening of catalyst-CO bonding. These results are similar to those previously observed in the case of thermal desorption of CO from potassium covered PI(III) single crystal.read more

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M AHMAD ,G S MCDOUGALL ,

Atmospheric pollution due to carbon monoxide from vehicular exhaust in Peshawar

Carbon monoxide is a major dr pollutant, its main source being vehicular exhaust. Peshawar, like other major cities is facing a serious problem of dr pollution due to rapidly increasing traffic. Carbon monoxide level during 600 hn to 1800 hrs was studied at sixteen different locations with maximum traffic density. Twelve cart of the sixteen locations were found to have an average carbon monoxide concentration above the threshold limits of 9 ppm for 8 hours exposure whereas, at one location average carbon monoxide concentration reached the limit of 35 ppm for one hour average exposure. Results suggest that at these twelve locations, the calculated carboxyhaemoglobin level that could be present in the blood of people exposed for 8 hours are in the range 204-4.85% which can adversely affect the central nervous system and can bring changes in psychomotor functions.read more

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M A KHATTAK ,M AKIF ,A R KHAN ,

Rapid determination of minor and trace metals in indigenous nonmetallic minerals

Using flame atomic absorption techniques, a rapid and sensitive method was developed for determination of minor and trace contents of copper, cobalt, nickel, zinc, lead, manganese, silver chromium and gold in indigenous non-metallic minerals (phosphorite and bauxite). Different mineral acids (HCl, H2SO4, HNO3) were used for the decomposition of the samples and HNO3 was found to be more suitable for digestion as compared to other acids. The instrumental conditions and other working parameters were optimised. The results obtained by the present method are found to be more reliable as compared to the other existing methods.read more

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K KHAN ,M RIAZ ,M A QAISER ,M MUMTAZ ,Y IQBAL ,

Field desorption mass spectrometry of organic acids and their salts

Negative field desorption mass spectra of 30 organic acids (mostly simple sulfonic acids) or their salts has been reported in this paper. Most of the acids studied give rise to the formation of simple negative ions in. [M - M]- or [M - salt option](-) Very low fragmentation or the parent molecules is observed. Addition of additive such as LiCl enhances the intensity of ion signals. Cluster of these molecules are also observed but their intensity is very Low.read more

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M SUBHAN ,

The coordination ability of N,N'-ethylene bis(2-amino 1-butanol) dihydrochloride towards transition and representative metals

N,N'-Ethylene Bis (2-amino 1-butanol) Dihydrochloride (EBAB) reacts with divalent first row transition and representative metals to give complexes of the stiochiometry,. MLX(2) when L = EBAB, M = Cu(II), Ni(II), Co(II), cd(II) and Hg(II) X = Cl-, Br-, NO3-. These complexes have been characterized by elemental analysis, conductivity measurements, room temperature magnetic moment studies, electronic and IR spectra The ligand in these complexes behaves as bidentate like substituted ethylenediamine coordinating through nitrogen atoms. The solid state IR study and other data support distorted tetrahedral geometry of the type MN(2)X(2).read more

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O REHMAN ,T ALI ,A RAUF ,S A KHAN ,

Spectrophotometric determination of iron with xylenol orange

Iron has been determined spectrophotometrically with xylenol orange as a chromogenic reagent 1:1 complex formed in highly acidic medium is measured for its absorbance as 585 nm In the present work, effect of buffer solution, reagent concentration, solute concentration, time, temperature and H2O2 has been studied. Interference of 23 cations and 5 anions is also reported.read more

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R N ASMA ,D E SHEHWAR ,A MAJEED ,M S ULLAH ,

Diazo-8-quinolinol coupling and spectrophotometric determination of aromatic amino compounds

Sulphamethoxazole and Sulphadiazine have been estimated in different concentration ranges, based on diazo-coupling with 8-Quinolinol followed by Spectrophotometric determination. The method is found to obey the Beer's Lambert law for the concentration as low at 1.3x10(-2) mg/ml.read more

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I HUSSAIN ,M AMINUDDIN ,

Kinetic spectrophotometric determination of nitrite by catalytic reaction of bromopyrogallol red and bromate

A sensitive kinetic spectrophotometric method for the determination of nitrite has been proposed, based on its catalytic effect on the oxidation of bromopyrogallol red (BPR) with bromate in sulphuric acid (0.15M). The decrease in absorbance at 467 nm is monitored spectrophotometrically after 5 min, with 20-1000 ng/ml nitrite. The presence of nitrate do not interfere me determination of nitrite. Coefficient of variation (C.V) for (n=10) was observed 0.866. The nitrite has been determined in water samples and results are compared with standard spectrophotometric method.read more

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

Flow injection analysis of hydrogen peroxide with peroxyoxalate chemiluminescence detection

A rapid and sensitive flow injection method is presented for the determination of hydrogen peroxide with chemiluminescence (CL) detection. CL is produced by the oxidation of bis(2,4,6-trichlorophenyl) oxalate by hydrogen peroxide in the presence of a fluorescent compound, perylene. The emission was monitored with a purpose-built now injection CL detector. ?he responses between hydrogen peroxide concentration and CL intensity were linear over me range of (1 x 10(-9) M(-1) x 10(-5) M) with a cv. of 5.6% for 10(-9) M hydrogen peroxide and 4.6 for 1 x 10(-5) M hydrogen peroxide.read more

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A RASHID ,M YAQOOB ,A NABI ,

Complexes of a Schiff base formed by the condensation of S-benzyl dithiocarbazate and benzoyl acetone

The synthesis and characterization of Co2+, Ni2+, CU2+, Pd2+, Cd2+ and Hg2+ complexes of benzoyl acetone hydrazine-S-benzyldithiocarbazate [H(2)BATC] are reported. Elemental analysis, magnetic moment and spectral [IR, UV-vis H-1-NMR and C-13-NMR] measurements have been used in characterize the complexes. ?he spectral data show that the ligand behaves in bidentate or tridentate manner. The stereochemistry or these complexes is discussed based upon their spectral and magnetic properties. The antibacterial activities of the ligand and its metal complexes toward various types of bacteria are also reported.read more

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A A SALAMAH ,M A S MONSHI ,N M A SALAM ,