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1
Content available remote Retention behaviour of Hg(II) and Pb(II) ions on a chemically modified, strongly basic anion-exchange resin: Effect of acid mixed with surfactant on the distribution coefficients of metal ions
Nabi S. A., Ganai S. A., Khan A. M.
Acta Chromatographica
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2008
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Vol. 20, no. 2
195-208
EN
Titan yellow has been adsorbed on a strongly basic anion-exchange resin. The effects of concentration, pH, time, and temperature on adsorption of the dye by the resin have been studied. The effects of surfactants on the distribution coefficients of metal ions were also studied. On the basis of distribution coefficients several binary separations of analytical importance (Zn(II) from Hg(II), Zn(II) from Pb(II), Cu(II) from Pb(II), Cd(II) from Pb(II), and Cu(II) from Hg(II) have been achieved on a column containing the Titan yellow-modified resin. Hg(II) and Pb(II) were selectively analysed in synthetic mixtures.
2
Content available remote Use of naphthol blue-black-modified Amberlite IRA-400 anion-exchange resin for separation of heavy metal ions
Nabi S. A., Naushad Mu., Ganai S. A.
Acta Chromatographica
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2007
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No. 18
180-189
EN
The potential of naphthol blue–black-modified Amberlite IRA-400 anion-exchange resin for separation of heavy metal pollutants has been explored. The distribution coefficients (Kd) of metal ions in several acidic solvent systems have been studied. The effect of the dissociation constant of the solvent on the distribution coefficient of metal ions has also been investigated. On the basis of Kd values, some analytically important binary separations (Al3+ from Co2+, Zn2+ from Ni2+, Zn2+ from Co2+, Ba2+ from Cd2+, Ca2+ from Co2+, Zn2+ from Zr4+, Al3+ from Zr4+, Pb2+ from Co2+, and Zn2+ from La3+) have been achieved. The practical applicability of the modified material has been demonstrated in the analysis of a synthetic mixture for selective separation of Zr4+.
3
Content available remote Thin-layer chromatographic separation of penicillins on stannic arsenate-cellulose layers
Nabi S. A., Khan M. A., Khowaja S. N., Alimuddin
Acta Chromatographica
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2006
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No. 16
164-172
EN
Thin-layer chromatographic separation of penicillins has been per-formed on stannic arsenate–cellulose layers. RF values of penicillins were determined after use of different mobile phases. Amoxycillin and ampicillin were selectively separated from binary and ternary synthetic mixtures. Amo-xycillin and ampicillin in commercially available drugs were also separated and were quantitatively determined.
4
Content available remote Chromatographic separations of metal ions on strong acid cation-exchange resin loaded with neutral red
Nabi S. A., Sheeba K. N., Khan M. A.
Acta Chromatographica
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2005
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No. 15
206-219
EN
The cation-exchange resin Amberlite IR-120 has been modified by adsorption of neutral red at pH 3.0. Several binary and ternary separations of important metal ions were achieved on the basis of their Kd values when chromatographed with different mobile phases. To demonstrate its practi-cal utility Zn2+ and Zr4+ were selectively separated from a synthetic mix-tures of metal ions on a column of the material. Zn2+ and Ca2+ ions were quantitatively separated and determined in the pharmaceutical preparation Zevit.
5
Content available remote Selective separation and determination of cephalosporins by TLC on stannic oxide layers
Nabi S. A., Laiq E., Islam A.
Acta Chromatographica
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2004
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No. 14
92-101
EN
The chromatographic behaviour of some cephalosporins has been studied on synthetic inorganic ion-exchanger (stannic oxide) layers using citrate and borate buffers as mobile phases. Several ternary and quaternary separations have been achieved. The utility of these separations has been demonstrated for estimation of cephalosporins in blood serum from pa-tients.
6
Content available remote Selective TLC separation of lysine and threonine in pharmaceutical preparations
Nabi S. A., Khan M. A.
Acta Chromatographica
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2003
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No. 13
161-171
EN
Thin-layer chromatography of α-amino acids has been performed on layers prepared from a 1:4 stannic arsenate-cellulose mixture. RF values of the amino acids were determined after development with a variety of mobile phases. Important synthetic ternary separations have been achieved on the basis of different RF values. Lysine and threonine have been selec-tively separated and quantitatively determined from among the mixture of amino acids present in a commercially available drug.
7
Content available remote Thin-layer chromatographic separations of some common pesticides on mixed stannic oxide-silica gel G layers
Nabi S. A., Gupta A., Khan M. A., Islam A.
Acta Chromatographica
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2002
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No. 12
201-210
EN
Thin-layer chromatography (TLC) of fourteen important organophos-phorus, organochlorine, and pyrethroid pesticides has been performed on mixed stannic oxide-silica gel G layers. The results of these studies reveal that this new combination has promising potential for separation of pesticides. RF values of these pesticides have been determined after development with a variety of mixed aqueous and organic mobile phases. Several important and difficult separations of synthetic pesticide mixtures were achieved on the basis of the different transport of the pesticides by the different mobile phases. The practical utility of these separations has been demonstrated by quantitative determination of monocrotophos, dimethoate, and malathion in soil samples.
8
Content available remote Studies of the adsorption of metal ions and the selective separation of the Ag+ ion on a strongly acidic cation-exchange resin modified with toluidine blue
Nabi S. A., Khan A. M. T.
Acta Chromatographica
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2002
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No. 12
129-142
EN
Cation-exchange resin Amberlite IR-120 has been modified by adsorption of toluidine blue at pH 6.0. Distribution coefficients, Kd, of important metal ions have been determined for use of different mobile phases. On the basis of these Kd values quantitative separations of metal ions of analytical utility have been achieved.
9
Content available remote Selective separation of metal ions on strong acid cation-exchange resin loaded with crystal violet
Nabi S. A., Laiq E., Islam A.
Acta Chromatographica
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2001
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No. 11
118-120
EN
The cation-exchange resin Amberlite IR-120 has been modified by adsorption of crystal violet at pH 7.0. Several binary and ternary separa-tions of important metal ions were achieved on the basis of their Kd values when chromatographed with different mobile phases. To explore the practical utility of this material Fe2+ and Al3+ were selectively separated from artificial mixtures of metal ions, and Zn2+ and Fe2+ present in three pharmaceutical preparations were also separated.
10
Content available remote Adsorption of metal ions on modified anion-exchange resin selective separation of Fe3+ and Hg2+ from other metals
Nabi S. A., Khan M. A., Islam A.
Acta Chromatographica
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2001
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No. 11
130-138
EN
Adsorption of alizarin red S on strong anion-exchange resin, Amber-lite IRA-400, and the use of the product to separate a variety of metal ions, have been studied. Distribution coefficients of several important metal ions have been determined with different mobile phases to explore the separation potential of these materials. Fe3+ and Hg2+ have been selectively separated from other heavy metal ions by use of a column packed with Amberlite IRA-400 treated with alizarin red S.
11
Content available remote Thin layer chromatographic separation and identification of pyrethroid insecticides on hydrated zirconium oxide layers
Nabi S. A., Islam A., Rahman N.
Acta Chromatographica
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2000
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No. 10
213-221
EN
The thin-layer chromatographic behavior of pyrethroid insecticides (cypermethrin, deltamethrin and fenvalerate) have been studied on hydrated zirconium oxide layers; detection was performed with iodine and o-tolidine reagent. The mobility of these insecticides was screened with several pure and mixed organic mobile phases. Methyl acetate–formic acid (80:20), ethanol–hexane (50:50), and acetone–cyclohexane (60:40) were found to be the most effective for achieving clear and distinct separations. The method has been used for the separation and detection of residues of these insecticides in wheat. Insecticide residues present in the sample at 1 μg levels can be detected by this technique.
12
Content available remote Separation of phenolic compounds on stannic arsenate-silica gel layers - quantitative separation and determination of phenolic pesticide residues in bananas
Nabi S. A., Sikarwar A.
Acta Chromatographica
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1999
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No. 9
123-132
EN
A thin-layer chromatographic method based on stannic arsenate–silica gel layers and simple and mixed mobile phases of different polarity has been developed for the separation of phenolic compounds. Banana fruit and plant-tissue samples were analysed for phenolic pesticide residues (m-nitrophenol, p-nitrophenol and p-aminophenol). The inter-molecular interaction of phenolic compounds and the effect of mobile phase on their affinity for the thin layer are also considered. Mutual separation and determination of m-nitrophenol, p-nitrophenol, picric acid and p-aminophenol is best achieved with ethanol–1.0 M citric acid, 1:3 (v/v). The accuracy and reproducibility of the method has been checked statistically. The limit of detection was found to be 0.20 μg L–1. Other important quantitative separations achieved were those of 2-chloro-3-pyridinol from chrysene and o-chlorophenol from citrinin and picric acid.
13
Content available remote Paper-electrophoretic studies of (-amino acids in citrate-phosphate buffer and sodium dodecyl sulphate mixed systems
Nabi S. A., Usmani S., Rahman N.
Acta Chromatographica
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1998
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No. 8
175-189
EN
The electrophoretic behaviour of 21 amino acids has been studied on Whatman No.1 paper strips in citrate-phosphate buffer systems of different pH. The role of sodium dodecyl sulphate (SDS) with citrate-phosphate buffer on the mobility of amino acids has been critically observed. It has been found that the presence of SDS in the citrate-phosphate buffer significantly enhances the separation possibilities. On the basis of the different migration of the amino acids, several important qualitative and quantitative separations have been achieved with these electrolyte systems. The practical utility of the method has been demon-strated by quantitative separation and determination of the amino acid constituents of the standard drugs Santevini (plus) and Astymin-3.
14
Content available remote Paper electrophoretic separation of phenolic compounds with acetate and citrate buffer electrolytes: determination of some important phenolic compounds in blood
Nabi S. A., Sikarwar A., Gupta A.
Acta Chromatographica
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1998
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No. 8
162-174
EN
Paper electrophoresis of 35 phenolic compounds has been performed with acetate and citrate buffers of varying pH. The study revealed a number of important binary and ternary separations. A few important quantitative separations were achieved: (i) resorcinol from quinol, catechol, coumaric acid, 3,4-dihydroxycinnamic acid and pyrogal-lol; (ii) a-naphthol from b-naphthol; and (iii) 4-nitrophenol from 2-nitro-phenol, 4-aminophenol, and picric acid. A new method is reported for rapid sample preparation for determination of free phenolic compounds and a few conjugated phenolic compounds in blood. Simultaneous separa-tion and determination of five phenolic compounds, quinol, resorcinol, coumaric acid, catechin and 3,4-dihydroxycinnamic acid was achieved by use of pH 3.67 citrate buffer; separation of gallic acid and 4-aminophenol was achieved by use of pH 3.62 acetate buffer. These results were then correlated with the general health and habits of the persons from whom the blood was taken. The accuracy and reproducibility of the method has been checked statistically. The limit of detection was found to be 0.20 μg L-1.
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