VOLUME 14, NO4, DEC 1992

UV-SPECTROPHOTOMETRIC FLOW-INJECTION DETERMINATION OF NITRATE USING ONLINE CHARCOAL COLUMN

A method is proposed for the determination of nitrate using ultraviolet spectrophotometry. The use of oxidized activated charcoal minicolumn on-line at an elevated pH eliminates organic and inorganic interferences. The absorbance is measured at 225 nm. The procedure has a limit of detection down to 1 mg l-1 with a relative standard deviation less than 1.0%.read more

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M MASOOM ,M YAQOOB ,

CHROMATOGRAPHIC STUDIES OF OXOVANADIUM(IV), PALLADIUM(II), COPPER(II) AND NICKEL(II) CHELATES OF SOME FLUORINATED TETRADENTATE SCHIFF-BASES

The oxovanadium(IV) complex of N,N-ethylenebis(1,1,1-trifluoro-6-methyl-5-hepten-2-oneimine) (H2F3AM2en), palladium(II) complex of N,N-1,2-propylene-bis (1,1,1-trifluoro-6-methyl-5-hepten-2-oneimine) (H2F3AM2pn) and oxovanadium(IV) and palladium(II) complexes of dl-N,N-stilbenebis(1,1,1-trifluoro-6-methyl-5-hepten-2-oneimine-(dl-H2F3AM2S) are prepared. Separation of the complexes together with their copper and nickel complexes am attempted by gas chromatography (GC) and reversed phase high performance liquid chromatography (HPLC). Copper, oxovanadium and palladium or nickel, oxovanadium and palladium complexes of dl-H2F3AM2S am separated by GC On the other hand, copper, nickel and palladium or copper, nickel and oxovanadium complexes am separated by reversed phase HPLC with Zorbax ODS column. The detection limits of F3AM2enVO, dl-F3AM2SVO and F3AM2pnPd are 10 ng, 5 ng and 10 nm, respectively.read more

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M Y KHUHAWAR ,A G BHATTI ,

ORGANOTIN COMPLEXES OF DONOR LIGANDS .2. INTRAMOLECULAR COORDINATION AND EVALUATION OF EQUILIBRIUM ENERGY FOR 1-NITROSO-2-NAPHTHOXY TIN DERIVATIVES BY DYNAMIC INFRARED

Dynamic infrared studies on 1-nitroso-2-naphthoxy organotin derivatives in temperature range 298-527 K have been carried out. Energy of equilibration, as calculated from Arrhenius equation, has been found between 2.15-4.849 KJ/K mole.read more

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SAQIB ALI ,M MAZHAR ,ABIDA KALDOOM ,R AHMAD ,ZAREEN AKHTAR ,MAQBOOL M BHATTI ,

QUANTITATION OF NITROGEN-DIOXIDE GENERATED IN PROPELLANT AND HIGH EXPLOSIVE BY POLAROGRAPHY

A method for determination of nitrogen dioxide in propellants and high explosives has been developed, based on collection of NO2 in a cartrige containing Florisil coated with diphenylamine. The nitrogen dioxide reacts with diphenylamine to form N-nitroso and nitrodiphenylamine derivatives which are eluted from the cartridge, analysed by polarography and related to the amount of NO2 generated in the sample. The utility of this method is exemplified by monitoring NO2 in some propellants and high explosives subjected to accelerated decomposition at higher temperature.read more

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SIKANDER ALI ARBANI ,A RAZAK SOMO ,G A QURESHI ,

VOLTAMMETRIC STUDIES ON SOME ANTIHYPERTENSIVE DRUGS AT PLATINUM TEST ELECTRODE

Labetalol (I) [36894-69 6] and methyldopa (II) 1555-30-61 were determined in pharmaceuticals by performing voltammetry at platinum test electrode vs Ag/AgCl reference eloctrode in sodium hydroxide, potassium hydroxide, hydrochloric acid and acetic acid systems. These compounds followed Ilkovic equation linearly upto 5 x 10(-4) Mole/dm3 with 98% reproducibility based on their oxidation potentials. Labetalol showed higher sensitivity in potassium hydroxide and sodium hydroxide, while methyldopa showed higher sensitivity in acetic acid system. Gold did not work when used as a test electrode. This method can be preferred to the reported methods for the determination of these drugs due to its better detection limits, reproducibility of the results, and less interference from dissolved oxygen.read more

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S MUNIBULLAH HUSSAINI ,S AZHAR ALI ,ABDUL SAMAD ,

INFRARED-SPECTRA OF DITHIOBENZOIC ACID AND ITS METAL-COMPLEXES

INFRARED-SPECTRA OF DITHIOBENZOIC ACID AND ITS METAL-COMPLEXESread more

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MUHAMMAD IKRAM ,

CONDUCTOMETRIC STUDIES ON SODIUM-PERCHLORATE AND SODIUM BENZOATE SOLUTIONS IN BINARY-MIXTURES OF ACETONITRILE WITH WATER 25-DEGREES-C

CONDUCTOMETRIC STUDIES ON SODIUM-PERCHLORATE AND SODIUM BENZOATE SOLUTIONS IN BINARY-MIXTURES OF ACETONITRILE WITH WATER 25-DEGREES-Cread more

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ABBAS KHAN ,M SADIQ KHANI NIAZI ,

CHAMAZULENE FROM MATRICARIA-CHAMOMILLA BY RESORPTION AND STEAM DISTILLATION

Matricaria chamomilla L is indigenous to Europe and was acclimatised in Pehsawar. The dried flowers on resorption and steam distillation furnished, volatile oil containing chamazulene.read more

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N AHMAD ,S FAROOQ ,LAJBER KHAN ,

SYNTHESIS AND SPECTROSCOPIC PROPERTIES OF 1-(ARYLTHIOALKYL)BENZOTRIAZOLES AND VINYL SULFIDES

A number of 1-(arylthioalkyl)benzotriazoles (2) and (6) have been prepared from compounds (1) And (5) respectively during reaction with BuLi and alkyl halides. The 1-(azylthioalkyl)benzotriazoles (2) and (6) were smoothly converted into their respective vinyl sulphides (3),(4) and (7) upon reaction with BF3-OEt2.read more

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AMIR SULTAN AFRIDI ,

CIRCULAR-DICHROISM STUDIES OF METAL-COMPLEXES WITH A CHIRAL SCHIFF-BASE - RR-TRANS-N,N-CYCLO HEXANE-BIS (1-PHENYL-5-IMINO-1,3-HEXADIONE)

A series of four metal complexes (M = VO2+, Co2+, Cu2+, UO2+) of a Schiff base RR-trans-N,N-1,2-cyclohexane-bis (1-phenyl-5-imino-1,3-hexadione[RR-chxn (HBAA)2]) have been characterized. Their infrared studies indicate that these metals are coordinated to four carbonyl oxygen atoms of the ligand while nitrogen atoms at azomethine remain uncoordinated. The circular dichroism and electronic absorption spectra of these complexes are measured in different solvents. The CD spectra of these chelates reveal more band multiplicity than do the corresponding absorption spectra. The CD spectra arc correlated to various electronic transitions originating from the ligand and d orbitals of the metal ion.read more

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U WAGNER ,MUHAMMAD ARIF MALIK ,NASIR AHMAD ,G SNATZKE ,ROSHAN AHMAD ,