VOLUME 16, NO1, MAR 1994

VISCOMETRIC BEHAVIOR OF BARIUM, LEAD AND COPPER POLYMETHACRYLATES IN ACIDIC MEDIUM

The viscosity behaviour of barium, lead and copper polymethacrylates in 1.0 M hydrochloric acid at 30-degrees-C has been reported for various concentrations. The concentration range studied conform to the viscosity behaviour explained on the basis of ionic radii. Barium polymethacrylate has lower viscosity than that for lead and copper polymethacrylates.read more

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R HUSSAIN ,D MOHAMMAD ,

THE STRUCTURE AND EXTENT OF SUPERMOLECULAR FORMATION IN AGED AQUEOUS POLY(VINYL ALCOHOL) SOLUTION

Two commercial samples of PVA were subjected to determine the supermolecular structure formation in aqueous media, by tight scattering and viscometric method. Solutions of various concentrations were aged upto 80 days and then, the intrinsic viscosity [eta], weight average molecular weight (Mw), radius of gyration (Rg2)1/2 were determined. From this, the extent of supermolecular formation of fresh solutions as well as the aged solutions was determined. It was found that supermolecular formation occurs to a lower degree during aging, and it increases with the concentration of the aging solution.read more

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N AHMAD ,B AHMAD ,U KALSOOM ,A SAEED ,

TEMPERATURE EFFECTS ON THE RESPONSE OF A RADIOCHROMIC FILM DOSIMETER

The dosimetric characteristics of a commercially available radiochromic thin plastic film (Gafchromic) dosimeter have been evaluated spectrophotometrically. The response curves at longer wavelengths (596 and 650 nm) show a linear response up to an absorbed doses of 2 kGy, whereas the response curves at shorter wavelengths (350, 375, 400, 450, 500 nm) are linear up to 5 kGy. If stored at room temperature (ca. 25-degrees-C) in dark, the pre-irradiation shelf-life of the film is more than 30 months. The dosimetric film also shows stable behaviour up to 40 days during post irradiation storage at room temperature in dark. The response is stable at lower temperature (-10 and 7-degrees-C) at 596 nm but shows some variations at 650 nm at higher doses, while at higher temperature (40-degrees-C) the response is unstable. The response shows increase in absorbance as the radiation chamber temperature increased from 0 to 46-degrees-C.read more

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H M KHAN ,M S WAHID ,

THERMALLY TREATED CHARCOAL - A SUBSTITUTE TO POROUS POLYMER PACKING MATERIAL FOR THE CHROMATOGRAPHIC ANALYSIS OF PERMANENT GASES

Activated charcoal has been thermally conditioned for the fabrication of gas chromatographic columns for the analysis of permanent gases. Effect of experimental parameters such as mobile phase velocity, length of column and sample volume on height equivalent to the theoretical plate and number of theoretical plates have been investigated. Efficiency of such columns has been compared with the column made of commercially available porous polymer packing materials. The comparison has been carried out by investigating chromatographic parameters like capacity factor, separation factor and column resolution. The effective use of charcoal column instead of porous polymer column has been proposed in a commercial gas analyzer.read more

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M RIAZ ,S B BUTT ,E U HAQ ,

A FAST LIQUID-CHROMATOGRAPHIC METHOD FOR THE DETERMINATION OF AMINO-ACIDS

A reversed-phase high performance liquid chromatographic (HPLC) procedure, using fluorescence detector, is outlined for the single and quantitative determination of trace amounts of amino acids in the ng 1(-1) by pre-column derivatisation. The optimisation of the operating conditions and possible separation mechanism for different amino acids in the chromatographic column am discussed. The fluorescence detection of the derivative has been a great advantage over the UV-detection system. The method can be used, however for the rapid determination of amino acids in complex biological samples.read more

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M AMINUDDIN ,J N MILLER ,

CATION-EXCHANGE SEPARATION OF TRANSITION-METALS AND CALCIUM WITH ZIRCONIUM-PHOSPHATE

The cation exchange behaviour of the divalent transition elements, manganese to copper and calcium was studied over zirconium phosphate dried at 35-degrees-C using hydrochloric acid as eluent. The adsorption of elements differ sufficiently as a function of hydrochloric acid concentration. The adsorption and the stability of the positively charged complexes is found to be in the order of Fe(II) > Ni(II) > Cu(II) > CA(II) > Co(II) > Mn(II).read more

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M L MIRZA ,N SAREECHA ,J IQBAL ,

FLOW-INJECTION ANALYSIS OF NAPHTHALENE AND SUBSTITUTED NAPHTHALENE DIALDEHYDE DERIVATIVES OF AMINO-ACIDS WITH FLUORESCENT DETECTION

A flow injection manifold incorporating fluorigenic reagent has been developed for the determination of glycine. The experimental approach is tittle different than from the usual procedure. A reverse flow injection analysis system is adopted in which the fluorigenic reagent has been injected into the non-segmented continuous carrier stream containing the buffer. Various factors which affect the fluorescence signal have been examined in this study in order to benefit from these findings.read more

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M AMINUDDIN ,J N MILLER ,

SYNTHESIS OF FLUORIGENIC REAGENT FOR THE DETECTION OF NH2 FUNCTIONAL-GROUPS

New fluorigenic reagent, 1-phenylnaphthalene-2,3-dicarboxaldehyde (thetaNDA) has been synthesised. This has been found useful for fluorescent detection of both proteins and amino acids.read more

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M AMINUDDIN ,J N MILLER ,

THE MAJOR, MINOR AND TRACE-ELEMENTS IN HENNA LEAVES

The major, minor and trace elements in Henna leaves of Faisalabad District, Pakistan present in the form of inorganic compounds or orgametallic complexes have been determined and the results are discussed.read more

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Z A KHAN ,I AHMAD ,M H SIDDIQUI ,

SYNTHESIS OF 2-ARYL AND 2-HETEROCYCLYL-2H-BENZO[E]-1,2,3,4-THIATRIAZIN-1,1-DIOXIDES

Several 2-(substituted) aryl-2H-benzo[e]-1,2,3,4-thiatriazin-1,1-dioxides (III) have been prepared in good yields, by the nitrosation of N-aryl-2-aminobenzenesulphonamides(II): derived from the reduction of corresponding N-aryl-2-nitrobenzenesulphonamides(I). 2-cyclohexyl, 2-benzyl and some heterocyclyl derivatives have also been prepared, the latter however, in lower yields. The mass spectra of these compounds show fragmentation patterns closely related to those observed in photolysis or thermolysis studies of such compounds. The infra-red spectra of these compounds have also been discussed.read more

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N H RAMA ,A SAEED ,