The potential of an inexpensive dithizone immobilized on ammonium lauryl sulfate alumina adsorben... more The potential of an inexpensive dithizone immobilized on ammonium lauryl sulfate alumina adsorbent to separate and preconcentrate traces of mercury from vegetables and ground water has been evaluated. A cartridge filled with 100 mg of adsorbent was incorporated to an on-line vapor generation accessory system. Traces of mercury in sample solutions were pumped through the cartridges for 2 min (flow rate of 5 mL min−1) and then eluted from the cartridges with 1 M hydrochloric acid for 1 min at a flow rate of 1 mL min−1. At the same time that mercury is eluted from the cartridges, the eluate is mixed with a 0.02% (m/v) sodium borohydride solution and the mercury cold vapor is swept through the atomization cell with a nitrogen flow of 50 mL min−1. The overall procedure (mercury separation-preconcentration and mercury cold vapor generation-atomization) is completed in around 3 min. The developed method achieves an enrichment factor of 125 with a limit of detection of 0.12 ng mL−1. The rep...
The concentration of cadmium and zinc in vegetables was determined by using an online flame atomi... more The concentration of cadmium and zinc in vegetables was determined by using an online flame atomic absorption spectrophotometer after simultaneous pre-concentration based on the complexation of Cd and Zn with 1,5-diphenylthiocarbazone immobilised on naphthalene. The effect of pH, sample flow rate and amount of 1,5-diphenylthiocarbazone on adsorption was investigated. After pre-concentration, Cd and Zn were eluted from the sorbent with hydrochloric acid. A pre-concentration factor of 20 and 33 was achieved for Cd and Zn, respectively. The calibration curve was linear in the range of 0.2-1 µg ml(-1) for Cd and Zn. The regression coefficients for the lines were 0.9914 and 0.9989 for Cd and Zn, respectively. The detection limits were calculated as three times the standard deviation of nine replicates of blanks: 0.00123 µg ml(-1) for Cd and 0.00176 µg ml(-1) for Zn.
A very simple, ultra-sensitive and fairly selective non-extractive spectrophotmetric method is pr... more A very simple, ultra-sensitive and fairly selective non-extractive spectrophotmetric method is presented for the rapid determination of mercury(II) at ultra-trace level using 1,5-diphenylthiocarbazone (dithizone) as a new micellar spectrophotometric reagent (lambdamax = 490 nm) in a slightly acidic (0.07 - 0.17 M H2SO4) aqueous solution. The presence of a micellar system avoids the previous steps of solvent extraction and reduces the cost, toxicity while enhancing the sensitivity, selectivity and the molar absorptivity. The reaction is instantaneous and the absorbance remains stable for over 24 h. The average molar absorption coefficient and Sandell's sensitivity were found to be 5.02 x 10(4) L mol(-1) cm(-1) and 10 ng cm(-2) of Hg, respectively. Linear calibration graphs were obtained for 0.05 - 10 mg L(-1) of Hg; the stoichiometric composition of the chelate is 1:2 (Hg:dithizone). The method is characterized by a detection limit of 1 microg L(-1) of Hg. Large excesses of over 60 cations, anions and complexing agents (e.g. EDTA, tartrate, oxalate, citrate, phosphate, thiourea, azide, SCN-) do not interfere in the determination. The method was successfully applied to a number of environmental water samples (potable and polluted), biological samples (human blood and urine; milk and fish) and soils; solutions contained both mercury(I) and mercury(II) as well as complex synthetic mixtures. The method has high precision and accuracy (s = +/-0.01 for 0.1 mg L(-1)).
ABSTRACT A simple, sensitive and low cost, flow injection time-based method was developed for on-... more ABSTRACT A simple, sensitive and low cost, flow injection time-based method was developed for on-line preconcentration and determination of nickel in textile effluent and soil samples. At the optimum pH, the nickel was retained on the sodium dodecyl sulphate (SDS) coated alumina modified with dithizone, and subsequently eluted with HCl and determined by flame atomic absorption spectrometry (FAAS). At a sample frequency of 30 h-1 and a 60 s preconcentration time, the enhancement factor was 100 and the detection limit was 0.54 µg L-1 (3σ). The accuracy of the developed method was sufficient and evaluated with spiked environmental samples.
ABSTRACT A rapid and sensitive method for the determination of trace levels of cadmium in cigaret... more ABSTRACT A rapid and sensitive method for the determination of trace levels of cadmium in cigarettes, soil, and blood samples by flame atomic absorption spectrometry (FAAS) has been developed. It is based on the online sorption of Cd(II) ions on a minicolumn packed by sodium dodecyl sulfate–coated alumina modified with dithizone. The optimum experimental parameters for the adsorption and desorption of cadmium were investigated. The recovery obtained was found to be 96% with preconcentration factor of 150. The calibration curve was linear between 50–600 µg/L Cd with a detection limit of 3 µg/L, sample frequency of 30 h−1 and reuse of column for 10 times without loss of sensitivity. The accuracy of the method was confirmed by applying the standard addition method and quantitative recoveries (95–99%) were obtained.
Spectrophotometric Determination of some Heavy Metals with Disphenylthiocarbazone in Micellar Med... more Spectrophotometric Determination of some Heavy Metals with Disphenylthiocarbazone in Micellar Media. Humaira Khan, Humaira Khan (2008) Spectrophotometric Determination of some Heavy Metals with Disphenylthiocarbazone in Micellar Media. ...
The synthesis of the adamantane phenylalkylamines 2a-d, 3a-c, and 4a-e is described. These compou... more The synthesis of the adamantane phenylalkylamines 2a-d, 3a-c, and 4a-e is described. These compounds exhibited significant antiproliferative activity, in vitro, against eight cancer cell lines tested. The σ(1), σ(2), and sodium channel binding affinities of compounds 2a, 3a, 4a, and 4c-e were investigated. The most interesting analogue, 4a, exhibited significant in vivo anticancer profile on pancreas, prostate, leukemia, and ovarian cancer cell line xenografts together with apoptosis and caspase-3 activation. Inhibition of the cancer cells cycle at the sub-G1 level was also obtained with 4a. Finally, encouraging results were observed with 4a in vivo on mice, suggesting putative antimetastatic and analgesic activities of this compound.
The potential of an inexpensive dithizone immobilized on ammonium lauryl sulfate alumina adsorben... more The potential of an inexpensive dithizone immobilized on ammonium lauryl sulfate alumina adsorbent to separate and preconcentrate traces of mercury from vegetables and ground water has been evaluated. A cartridge filled with 100 mg of adsorbent was incorporated to an on-line vapor generation accessory system. Traces of mercury in sample solutions were pumped through the cartridges for 2 min (flow rate of 5 mL min−1) and then eluted from the cartridges with 1 M hydrochloric acid for 1 min at a flow rate of 1 mL min−1. At the same time that mercury is eluted from the cartridges, the eluate is mixed with a 0.02% (m/v) sodium borohydride solution and the mercury cold vapor is swept through the atomization cell with a nitrogen flow of 50 mL min−1. The overall procedure (mercury separation-preconcentration and mercury cold vapor generation-atomization) is completed in around 3 min. The developed method achieves an enrichment factor of 125 with a limit of detection of 0.12 ng mL−1. The rep...
The concentration of cadmium and zinc in vegetables was determined by using an online flame atomi... more The concentration of cadmium and zinc in vegetables was determined by using an online flame atomic absorption spectrophotometer after simultaneous pre-concentration based on the complexation of Cd and Zn with 1,5-diphenylthiocarbazone immobilised on naphthalene. The effect of pH, sample flow rate and amount of 1,5-diphenylthiocarbazone on adsorption was investigated. After pre-concentration, Cd and Zn were eluted from the sorbent with hydrochloric acid. A pre-concentration factor of 20 and 33 was achieved for Cd and Zn, respectively. The calibration curve was linear in the range of 0.2-1 µg ml(-1) for Cd and Zn. The regression coefficients for the lines were 0.9914 and 0.9989 for Cd and Zn, respectively. The detection limits were calculated as three times the standard deviation of nine replicates of blanks: 0.00123 µg ml(-1) for Cd and 0.00176 µg ml(-1) for Zn.
A very simple, ultra-sensitive and fairly selective non-extractive spectrophotmetric method is pr... more A very simple, ultra-sensitive and fairly selective non-extractive spectrophotmetric method is presented for the rapid determination of mercury(II) at ultra-trace level using 1,5-diphenylthiocarbazone (dithizone) as a new micellar spectrophotometric reagent (lambdamax = 490 nm) in a slightly acidic (0.07 - 0.17 M H2SO4) aqueous solution. The presence of a micellar system avoids the previous steps of solvent extraction and reduces the cost, toxicity while enhancing the sensitivity, selectivity and the molar absorptivity. The reaction is instantaneous and the absorbance remains stable for over 24 h. The average molar absorption coefficient and Sandell's sensitivity were found to be 5.02 x 10(4) L mol(-1) cm(-1) and 10 ng cm(-2) of Hg, respectively. Linear calibration graphs were obtained for 0.05 - 10 mg L(-1) of Hg; the stoichiometric composition of the chelate is 1:2 (Hg:dithizone). The method is characterized by a detection limit of 1 microg L(-1) of Hg. Large excesses of over 60 cations, anions and complexing agents (e.g. EDTA, tartrate, oxalate, citrate, phosphate, thiourea, azide, SCN-) do not interfere in the determination. The method was successfully applied to a number of environmental water samples (potable and polluted), biological samples (human blood and urine; milk and fish) and soils; solutions contained both mercury(I) and mercury(II) as well as complex synthetic mixtures. The method has high precision and accuracy (s = +/-0.01 for 0.1 mg L(-1)).
ABSTRACT A simple, sensitive and low cost, flow injection time-based method was developed for on-... more ABSTRACT A simple, sensitive and low cost, flow injection time-based method was developed for on-line preconcentration and determination of nickel in textile effluent and soil samples. At the optimum pH, the nickel was retained on the sodium dodecyl sulphate (SDS) coated alumina modified with dithizone, and subsequently eluted with HCl and determined by flame atomic absorption spectrometry (FAAS). At a sample frequency of 30 h-1 and a 60 s preconcentration time, the enhancement factor was 100 and the detection limit was 0.54 µg L-1 (3σ). The accuracy of the developed method was sufficient and evaluated with spiked environmental samples.
ABSTRACT A rapid and sensitive method for the determination of trace levels of cadmium in cigaret... more ABSTRACT A rapid and sensitive method for the determination of trace levels of cadmium in cigarettes, soil, and blood samples by flame atomic absorption spectrometry (FAAS) has been developed. It is based on the online sorption of Cd(II) ions on a minicolumn packed by sodium dodecyl sulfate–coated alumina modified with dithizone. The optimum experimental parameters for the adsorption and desorption of cadmium were investigated. The recovery obtained was found to be 96% with preconcentration factor of 150. The calibration curve was linear between 50–600 µg/L Cd with a detection limit of 3 µg/L, sample frequency of 30 h−1 and reuse of column for 10 times without loss of sensitivity. The accuracy of the method was confirmed by applying the standard addition method and quantitative recoveries (95–99%) were obtained.
Spectrophotometric Determination of some Heavy Metals with Disphenylthiocarbazone in Micellar Med... more Spectrophotometric Determination of some Heavy Metals with Disphenylthiocarbazone in Micellar Media. Humaira Khan, Humaira Khan (2008) Spectrophotometric Determination of some Heavy Metals with Disphenylthiocarbazone in Micellar Media. ...
The synthesis of the adamantane phenylalkylamines 2a-d, 3a-c, and 4a-e is described. These compou... more The synthesis of the adamantane phenylalkylamines 2a-d, 3a-c, and 4a-e is described. These compounds exhibited significant antiproliferative activity, in vitro, against eight cancer cell lines tested. The σ(1), σ(2), and sodium channel binding affinities of compounds 2a, 3a, 4a, and 4c-e were investigated. The most interesting analogue, 4a, exhibited significant in vivo anticancer profile on pancreas, prostate, leukemia, and ovarian cancer cell line xenografts together with apoptosis and caspase-3 activation. Inhibition of the cancer cells cycle at the sub-G1 level was also obtained with 4a. Finally, encouraging results were observed with 4a in vivo on mice, suggesting putative antimetastatic and analgesic activities of this compound.
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