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Analytica Chimica Acta (v.547, #1)
Mercury(II) binding to thiol-functionalized mesoporous silicas: critical effect of pH and sorbent properties on capacity and selectivity by Alain Walcarius; Cyril Delacôte (pp. 3-13).
The binding properties of mesoporous thiol-functionalized silica sorbents towards mercury(II) species were studied as a function of pH in a wide range (0â8), in the absence or in the presence of competing metal ions, from batch equilibration experiments. To this end, a series of thiol-functionalized adsorbents characterized by different structures (from completely disordered amorphous solids to highly ordered mesostructures), variable density of organic ligands (from 1 to 4mmolgâ1), and various degrees of porosity, have been prepared either by post-synthesis grafting or by the co-condensation route. Hg(II) binding to these thiol-functionalized silica samples is strongly dependent on pH, especially in acidic medium (pH<4) where non-hydrolyzed Hg2+ species become dominant. This behavior was found to be significantly affected by the degree of structural organization of the materials (amorphous or ordered mesoporous solids, short-range versus long-range structural order) and the adsorbent composition (density of functional groups). A beneficial effect of high structural order was observed in both the capacity (access to a high number of binding sites) and selectivity (towards other metal ions) for the ordered mesoporous sorbents in comparison to the amorphous gels, but this was only true for pH values down to 4, where Hg(II) species are mainly in the form of Hg(OH)2. In more acidic medium, however, the sorption of the non-hydrolyzed Hg2+ species underwent dramatic loss of effectiveness, which resulted in both lower capacities and worse selectivity. These restrictions were more marked when increasing the density of functional groups in the materials and, to lesser extent, when decreasing their level of structural ordering. They were interpreted on the basis of electrostatic considerations as the binding of Hg2+ to thiol groups leads to the generation of positively charged complexes in the host material while that of Hg(OH)2 involves the formation of neutral moieties. Possible regeneration of sorbents and re-use were also discussed.
Keywords: Mercury(II); Thiol-functionalized mesoporous silica; Solid/liquid extraction; Sorption capacity and selectivity
Mercury(II) binding to thiol-functionalized mesoporous silicas: critical effect of pH and sorbent properties on capacity and selectivity by Alain Walcarius; Cyril DelacĂŽte (pp. 3-13).
The binding properties of mesoporous thiol-functionalized silica sorbents towards mercury(II) species were studied as a function of pH in a wide range (0â8), in the absence or in the presence of competing metal ions, from batch equilibration experiments. To this end, a series of thiol-functionalized adsorbents characterized by different structures (from completely disordered amorphous solids to highly ordered mesostructures), variable density of organic ligands (from 1 to 4mmolgâ1), and various degrees of porosity, have been prepared either by post-synthesis grafting or by the co-condensation route. Hg(II) binding to these thiol-functionalized silica samples is strongly dependent on pH, especially in acidic medium (pH<4) where non-hydrolyzed Hg2+ species become dominant. This behavior was found to be significantly affected by the degree of structural organization of the materials (amorphous or ordered mesoporous solids, short-range versus long-range structural order) and the adsorbent composition (density of functional groups). A beneficial effect of high structural order was observed in both the capacity (access to a high number of binding sites) and selectivity (towards other metal ions) for the ordered mesoporous sorbents in comparison to the amorphous gels, but this was only true for pH values down to 4, where Hg(II) species are mainly in the form of Hg(OH)2. In more acidic medium, however, the sorption of the non-hydrolyzed Hg2+ species underwent dramatic loss of effectiveness, which resulted in both lower capacities and worse selectivity. These restrictions were more marked when increasing the density of functional groups in the materials and, to lesser extent, when decreasing their level of structural ordering. They were interpreted on the basis of electrostatic considerations as the binding of Hg2+ to thiol groups leads to the generation of positively charged complexes in the host material while that of Hg(OH)2 involves the formation of neutral moieties. Possible regeneration of sorbents and re-use were also discussed.
Keywords: Mercury(II); Thiol-functionalized mesoporous silica; Solid/liquid extraction; Sorption capacity and selectivity
Determination of copper, cadmium and lead in seawater and mineral water by flame atomic absorption spectrometry after coprecipitation with aluminum hydroxide by G. Doner; A. Ege (pp. 14-17).
An aluminum hydroxide coprecipitation method for the determination of cadmium, copper and lead by flame atomic absorption spectrometry in aqueous solutions, seawater and mineral water samples has been investigated. The coprecipitation conditions, such as the effect of the pH, the amount of carrier element, the effect of possible matrix ions and the time were examined in detail for the studied elements. It was found that cadmium, copper and lead are co-precipitated quantitatively (â„95%) with aluminum hydroxide at pH 7 with low R.S.D. values of around 2 to 3%. Detection limits (38) were 6ngmlâ1 for Cd, 3ngmlâ1 for Cu and 16ngmlâ1 for Pb. The method proposed was validated by the analysis of HPS 312205 seawater standard reference material and spiked mineral water samples.
Keywords: Coprecipitation; Aluminum hydroxide; Seawater; Mineral water; Cu; Cd; Pb; FAAS
Determination of copper, cadmium and lead in seawater and mineral water by flame atomic absorption spectrometry after coprecipitation with aluminum hydroxide by G. Doner; A. Ege (pp. 14-17).
An aluminum hydroxide coprecipitation method for the determination of cadmium, copper and lead by flame atomic absorption spectrometry in aqueous solutions, seawater and mineral water samples has been investigated. The coprecipitation conditions, such as the effect of the pH, the amount of carrier element, the effect of possible matrix ions and the time were examined in detail for the studied elements. It was found that cadmium, copper and lead are co-precipitated quantitatively (â„95%) with aluminum hydroxide at pH 7 with low R.S.D. values of around 2 to 3%. Detection limits (38) were 6ngmlâ1 for Cd, 3ngmlâ1 for Cu and 16ngmlâ1 for Pb. The method proposed was validated by the analysis of HPS 312205 seawater standard reference material and spiked mineral water samples.
Keywords: Coprecipitation; Aluminum hydroxide; Seawater; Mineral water; Cu; Cd; Pb; FAAS
Gold recovery onto poly(acrylamide-allylthiourea) hydrogels synthesized by treating with gamma radiation by A. GĂŒlden Kılıç; SavaĆ Malcı; ĂmĂŒr Ăelikbıçak; Nurettin Ćahiner; Bekir Salih (pp. 18-25).
Poly(acrylamide-1-allyl-2-thiourea) hydrogels, Poly(AAm-ATU), were synthesized by gamma irradiation using a60Co Îł source at different irradiation dose rates and in a monomer mixture with different 1-allyl-2-thiourea contents. These hydrogels were used for the specific gold recovery from single and competitive media. It was observed that the gold adsorption capacity onto the hydrogels was high at low pHs and reached a maximum value at pH 0.5. It was found that the adsorption capacity of the hydrogels for gold ions in acidic media around pH 0.5 was high and about 940mggâ1 dry hydrogel. Adsorption of these hydrogels for gold ions was found to be very fast and also these hydrogels were showed extremely high selectivity to the gold ions in acidic media even when the concentrations of the other metal ions were extremely higher than that of the gold. Because of the high specificity of these hydrogels to gold ions compared with the other metal ions at low pHs, all matrix effects could be easily eliminated by adsorbing gold ions onto the hydrogels at around pH 0.5 and desorbing into 0.8M thiourea in 3.0M HCl. The swellability of the synthesized hydrogels varied with irradiation dose rates and increased at high irradiation dose rates. The minimum swellability of the hydrogels was found to be at least 1000% which made it attractive for gold to penetrate into the hydrogels and react with all the functional groups in the interior surface of the hydrogels.
Keywords: Acryl amide; 1-Allyl-2-thiourea; Hydrogels; Îł-Irradiation; Swelling; Characterization; Gold recovery; Matrix elimination
Gold recovery onto poly(acrylamide-allylthiourea) hydrogels synthesized by treating with gamma radiation by A. GĂŒlden Kılıç; SavaĆ Malcı; ĂmĂŒr Ăelikbıçak; Nurettin Ćahiner; Bekir Salih (pp. 18-25).
Poly(acrylamide-1-allyl-2-thiourea) hydrogels, Poly(AAm-ATU), were synthesized by gamma irradiation using a60Co Îł source at different irradiation dose rates and in a monomer mixture with different 1-allyl-2-thiourea contents. These hydrogels were used for the specific gold recovery from single and competitive media. It was observed that the gold adsorption capacity onto the hydrogels was high at low pHs and reached a maximum value at pH 0.5. It was found that the adsorption capacity of the hydrogels for gold ions in acidic media around pH 0.5 was high and about 940mggâ1 dry hydrogel. Adsorption of these hydrogels for gold ions was found to be very fast and also these hydrogels were showed extremely high selectivity to the gold ions in acidic media even when the concentrations of the other metal ions were extremely higher than that of the gold. Because of the high specificity of these hydrogels to gold ions compared with the other metal ions at low pHs, all matrix effects could be easily eliminated by adsorbing gold ions onto the hydrogels at around pH 0.5 and desorbing into 0.8M thiourea in 3.0M HCl. The swellability of the synthesized hydrogels varied with irradiation dose rates and increased at high irradiation dose rates. The minimum swellability of the hydrogels was found to be at least 1000% which made it attractive for gold to penetrate into the hydrogels and react with all the functional groups in the interior surface of the hydrogels.
Keywords: Acryl amide; 1-Allyl-2-thiourea; Hydrogels; Îł-Irradiation; Swelling; Characterization; Gold recovery; Matrix elimination
A novel preconcentration method for determination of iron and lead using Chromosorb-103 and flame atomic absorption spectrometry by Yasemin Bakircioglu; Dilek Bakircioglu; Nilgun Tokman (pp. 26-30).
Syringe connected-minicolumn (SCM) method for the preconcentration/separation of iron and lead prior to their determination by flame atomic absorption spectrometry (FAAS) was developed. The proposed method is substituted for classical batch and column methods. The method proposed was compared with the column method with respect to easiness, rapidness, simplicity and some analytical performance criteria such as recovery, precision, accuracy and risk of contamination. A minicolumn was filled with Chromosorb-103 as a sorbent and connected with a syringe. The experimental conditions such as pH of sample, concentration and amount of eluent, flow rates of sample and eluent, concentration of 8-hydroxyquinoline (oxine) as a complexing agent were optimized. The sample solution with or without oxine was drawn into the syringe and discharged manually passing through the resin. Analytes were retained at pH â„5 and eluted with 1M nitric acid in acetone quantitatively. Analyte elements could be concentrated up to 200-fold. The iron and lead in river-water samples and in certified reference Bovine Liver (NIST 1577b) were quantitatively recovered with relative standard deviation lower than 10%.
Keywords: Syringe-connected minicolumn method; Flame atomic absorption spectrometry; Solid phase extraction; Chromosorb-103; Bovine liver
A novel preconcentration method for determination of iron and lead using Chromosorb-103 and flame atomic absorption spectrometry by Yasemin Bakircioglu; Dilek Bakircioglu; Nilgun Tokman (pp. 26-30).
Syringe connected-minicolumn (SCM) method for the preconcentration/separation of iron and lead prior to their determination by flame atomic absorption spectrometry (FAAS) was developed. The proposed method is substituted for classical batch and column methods. The method proposed was compared with the column method with respect to easiness, rapidness, simplicity and some analytical performance criteria such as recovery, precision, accuracy and risk of contamination. A minicolumn was filled with Chromosorb-103 as a sorbent and connected with a syringe. The experimental conditions such as pH of sample, concentration and amount of eluent, flow rates of sample and eluent, concentration of 8-hydroxyquinoline (oxine) as a complexing agent were optimized. The sample solution with or without oxine was drawn into the syringe and discharged manually passing through the resin. Analytes were retained at pH â„5 and eluted with 1M nitric acid in acetone quantitatively. Analyte elements could be concentrated up to 200-fold. The iron and lead in river-water samples and in certified reference Bovine Liver (NIST 1577b) were quantitatively recovered with relative standard deviation lower than 10%.
Keywords: Syringe-connected minicolumn method; Flame atomic absorption spectrometry; Solid phase extraction; Chromosorb-103; Bovine liver
Synthesis, characterization and application of a novel sorbent, glucamine-modified MCM-41, for the removal/preconcentration of boron from waters by Ăznur Kaftan; MĂŒge Açıkel; Ahmet E. EroÄlu; Talal Shahwan; Levent Artok; Chaoying Ni (pp. 31-41).
A novel sorbent was prepared by the functionalization of an inorganic support material, MCM-41, with N-methylglucamine for the uptake of boron from aqueous solutions prior to its determination by inductively coupled plasma optical emission spectrometry (ICPâOES). Characterization of the newly synthesized material was performed using BET, XRD, TEM, SEM and DRIFTS techniques, in addition to its C and N elemental content. Sorption behavior of the novel sorbent for boron was also investigated and found to obey Freundlich and DubininâRadushkevich (DâR) isotherm models. The maximum amount of B (as H3BO3) that can be sorbed by the sorbent was calculated from the DâR isotherm and was found to be 0.8mmol Bgâ1 of sorbent. The applicability of the new sorbent for the removal/preconcentration of boron from aqueous samples was examined by batch method. It was found that the sorbent can take up 85% of boron in 5min whereas quantitative sorption is obtained in 30min. Any pH greater than 6 can be used for sorption. Desorption from the sorbent was carried out using 1.0M HNO3. The sorption efficiency of the new sorbent was also compared to that of Amberlite IRA 743, a commercial resin with N-methylglucamine functional groups. Within the experimental conditions employed, the new sorbent was found to have higher sorption efficiency than the commercial resin. For method validation, spike recovery tests were performed at various concentration levels in different water types and were found to be between 83â95 and 75â92% for ultra pure water and geothermal water, respectively.
Keywords: Boron; Inductively coupled plasma optical emission spectrometry; ICPâOES; Functionalization; MCM-41; N; -methylglucamine; Amberlite IRA 743
Synthesis, characterization and application of a novel sorbent, glucamine-modified MCM-41, for the removal/preconcentration of boron from waters by Ăznur Kaftan; MĂŒge Açıkel; Ahmet E. EroÄlu; Talal Shahwan; Levent Artok; Chaoying Ni (pp. 31-41).
A novel sorbent was prepared by the functionalization of an inorganic support material, MCM-41, with N-methylglucamine for the uptake of boron from aqueous solutions prior to its determination by inductively coupled plasma optical emission spectrometry (ICPâOES). Characterization of the newly synthesized material was performed using BET, XRD, TEM, SEM and DRIFTS techniques, in addition to its C and N elemental content. Sorption behavior of the novel sorbent for boron was also investigated and found to obey Freundlich and DubininâRadushkevich (DâR) isotherm models. The maximum amount of B (as H3BO3) that can be sorbed by the sorbent was calculated from the DâR isotherm and was found to be 0.8mmol Bgâ1 of sorbent. The applicability of the new sorbent for the removal/preconcentration of boron from aqueous samples was examined by batch method. It was found that the sorbent can take up 85% of boron in 5min whereas quantitative sorption is obtained in 30min. Any pH greater than 6 can be used for sorption. Desorption from the sorbent was carried out using 1.0M HNO3. The sorption efficiency of the new sorbent was also compared to that of Amberlite IRA 743, a commercial resin with N-methylglucamine functional groups. Within the experimental conditions employed, the new sorbent was found to have higher sorption efficiency than the commercial resin. For method validation, spike recovery tests were performed at various concentration levels in different water types and were found to be between 83â95 and 75â92% for ultra pure water and geothermal water, respectively.
Keywords: Boron; Inductively coupled plasma optical emission spectrometry; ICPâOES; Functionalization; MCM-41; N; -methylglucamine; Amberlite IRA 743
Preconcentration and atomic spectrometric determination of rare earth elements (REEs) in natural water samples by inductively coupled plasma atomic emission spectrometry by TĂŒrker Pasinli; Ahmet E. EroÄlu; Talal Shahwan (pp. 42-49).
The usage of a variety of sorbents has been shown as promising matrix removal/preconcentration strategies for the determination of rare earth elements (REEs) in various natural water samples by inductively coupled plasma atomic emission spectrometry (ICP-AES). The sorption efficiency of various zeolites (clinoptilolite, mordenite, zeolite Y, zeolite Beta), ion-exchangers (Amberlite CG-120, Amberlite IR-120, Rexyn 101, Dowex 50W X18) and chelating resins (Muromac, Chelex 100, Amberlite IRC-718) towards REEs was investigated in terms of solution pH, shaking time and sorbent amount. The results have shown that most of the materials can take up REEs at a wide pH range. The experiments were continued with clinoptilolite, zeolite Y and Chelex 100 and it was demonstrated that all three materials displayed very fast kinetics for REE sorption (higher than 96% in 1 min). Desorption from the sorbents was realized with 2.0M HNO3 for clinoptilolite and 0.1M HNO3 for zeolite Y and Chelex 100. Only the lower concentration range (0.01â2.0mglâ1) of matrix-matched standards were used in quantitation although the calibration graphs were linear at least up to 10.0mglâ1 for all REEs studied. The limit of detection (3s) without preconcentration was 0.1, 1.0, and 0.2ÎŒglâ1 for Eu, La, and Yb, respectively. The validity of the method with the selected sorbents was checked through spike recovery experiments.
Keywords: Rare earth elements; Inductively coupled plasma atomic emission spectrometry (ICP-AES); Preconcentration; Clinoptilolite; Zeolite Y; Chelex 100
Preconcentration and atomic spectrometric determination of rare earth elements (REEs) in natural water samples by inductively coupled plasma atomic emission spectrometry by TĂŒrker Pasinli; Ahmet E. EroÄlu; Talal Shahwan (pp. 42-49).
The usage of a variety of sorbents has been shown as promising matrix removal/preconcentration strategies for the determination of rare earth elements (REEs) in various natural water samples by inductively coupled plasma atomic emission spectrometry (ICP-AES). The sorption efficiency of various zeolites (clinoptilolite, mordenite, zeolite Y, zeolite Beta), ion-exchangers (Amberlite CG-120, Amberlite IR-120, Rexyn 101, Dowex 50W X18) and chelating resins (Muromac, Chelex 100, Amberlite IRC-718) towards REEs was investigated in terms of solution pH, shaking time and sorbent amount. The results have shown that most of the materials can take up REEs at a wide pH range. The experiments were continued with clinoptilolite, zeolite Y and Chelex 100 and it was demonstrated that all three materials displayed very fast kinetics for REE sorption (higher than 96% in 1 min). Desorption from the sorbents was realized with 2.0M HNO3 for clinoptilolite and 0.1M HNO3 for zeolite Y and Chelex 100. Only the lower concentration range (0.01â2.0mglâ1) of matrix-matched standards were used in quantitation although the calibration graphs were linear at least up to 10.0mglâ1 for all REEs studied. The limit of detection (3s) without preconcentration was 0.1, 1.0, and 0.2ÎŒglâ1 for Eu, La, and Yb, respectively. The validity of the method with the selected sorbents was checked through spike recovery experiments.
Keywords: Rare earth elements; Inductively coupled plasma atomic emission spectrometry (ICP-AES); Preconcentration; Clinoptilolite; Zeolite Y; Chelex 100
Electro-adsorption of polyethyleneimine on the anion exchange membrane by Mourad Amara; Hacène Kerdjoudj (pp. 50-52).
Anion exchange membrane has been modified by fixation of polyethyleneimine. The modification has been carried out aiming to achieve a separation of anions according to their hydration radii and their sizes. The performances of the modified membranes were compared with the unmodified one by applying Donnan dialysis of nitrate ion using Clâ in the strip compartment. The transfer of nitrate ions in the presence of chloride was enhanced by using immersion modified membrane. The presence of a thin layer of PEI on the strip side of the membrane improves Clâ transference, by creating a chemical potential difference which increases the transfer.
Keywords: Membrane modification; Selectivity; Polyethyleneimine; Nitrate
Electro-adsorption of polyethyleneimine on the anion exchange membrane by Mourad Amara; HacĂšne Kerdjoudj (pp. 50-52).
Anion exchange membrane has been modified by fixation of polyethyleneimine. The modification has been carried out aiming to achieve a separation of anions according to their hydration radii and their sizes. The performances of the modified membranes were compared with the unmodified one by applying Donnan dialysis of nitrate ion using Clâ in the strip compartment. The transfer of nitrate ions in the presence of chloride was enhanced by using immersion modified membrane. The presence of a thin layer of PEI on the strip side of the membrane improves Clâ transference, by creating a chemical potential difference which increases the transfer.
Keywords: Membrane modification; Selectivity; Polyethyleneimine; Nitrate
A study on the utility of bismuth-film electrodes for the determination of In(III) in the presence of Pb(II) and Cd(II) by square wave anodic stripping voltammetry by Andreas Charalambous; Anastasios Economou (pp. 53-58).
This work is an investigation into the utility of bismuth-film electrodes (BiFEs) for the determination of indium in the presence of cadmium and lead by square wave anodic stripping voltammetry (SWASV). The purpose of this study was to demonstrate that, after judicious choice of the associated chemical and instrumental conditions, it is possible to achieve satisfactory separation of the relevant stripping peak and, thus, to determine simultaneously trace concentrations of cadmium, lead and indium. It was conclusively demonstrated that a BiFE performed better than the equivalent mercury-film electrode (MFE) in this particular application.
Keywords: Indium; Cadmium; Lead; Anodic stripping voltammetry; Bismuth-film electrodes
A study on the utility of bismuth-film electrodes for the determination of In(III) in the presence of Pb(II) and Cd(II) by square wave anodic stripping voltammetry by Andreas Charalambous; Anastasios Economou (pp. 53-58).
This work is an investigation into the utility of bismuth-film electrodes (BiFEs) for the determination of indium in the presence of cadmium and lead by square wave anodic stripping voltammetry (SWASV). The purpose of this study was to demonstrate that, after judicious choice of the associated chemical and instrumental conditions, it is possible to achieve satisfactory separation of the relevant stripping peak and, thus, to determine simultaneously trace concentrations of cadmium, lead and indium. It was conclusively demonstrated that a BiFE performed better than the equivalent mercury-film electrode (MFE) in this particular application.
Keywords: Indium; Cadmium; Lead; Anodic stripping voltammetry; Bismuth-film electrodes
The electrochemical behavior of some podands at a benzo[ c]cinnoline modified glassy carbon electrode by AybĂŒke A. Ä°sbŃr; Ali Osman Solak; Zafer ĂstĂŒndaÄ; Selen BŃlge; Amgalan Natsagdorj; Emine Kiliç; Zeynel Kiliç (pp. 59-63).
This paper describes the grafting of benzo[ c]cinnoline (BCC) molecules on glassy carbon (GC) electrode surface. The attachment of BCC molecules to carbon substrate is induced by the electrochemical reduction of the corresponding diazonium salt. The modification of GC with BCC diazonium salt was done in aprotic solution and proved by blocking of dopamine electron transfer. The presence of BCC at the GC surface was characterized by cyclic voltammetry and X-ray photoelectron spectroscopy (XPS). On modified surface, the electrochemical behavior of two different types of podands and the catalytic effects of the GC-BCC surface were studied. The XPS was used to monitor element characteristics of the adsorbates on the GC surface and confirm the attachment of BCC molecules to the GC surface.
Keywords: Benzo[; c; ]cinnoline; Podand; XPS; Cyclic voltammetry; Glassy carbon electrode; Benzo[; c; ]cinnoline modification
The electrochemical behavior of some podands at a benzo[ c]cinnoline modified glassy carbon electrode by AybĂŒke A. Ä°sbŃr; Ali Osman Solak; Zafer ĂstĂŒndaÄ; Selen BŃlge; Amgalan Natsagdorj; Emine Kiliç; Zeynel Kiliç (pp. 59-63).
This paper describes the grafting of benzo[ c]cinnoline (BCC) molecules on glassy carbon (GC) electrode surface. The attachment of BCC molecules to carbon substrate is induced by the electrochemical reduction of the corresponding diazonium salt. The modification of GC with BCC diazonium salt was done in aprotic solution and proved by blocking of dopamine electron transfer. The presence of BCC at the GC surface was characterized by cyclic voltammetry and X-ray photoelectron spectroscopy (XPS). On modified surface, the electrochemical behavior of two different types of podands and the catalytic effects of the GC-BCC surface were studied. The XPS was used to monitor element characteristics of the adsorbates on the GC surface and confirm the attachment of BCC molecules to the GC surface.
Keywords: Benzo[; c; ]cinnoline; Podand; XPS; Cyclic voltammetry; Glassy carbon electrode; Benzo[; c; ]cinnoline modification
Direct determination of kanamycin in raw materials, veterinary formulation and culture media using a novel liquid chromatographyâevaporative light scattering method by N.C. Megoulas; M.A. Koupparis (pp. 64-72).
A novel method for the direct determination of kanamycin A and its minor component kanamycin B was developed and validated based on reversed phase liquid chromatography with evaporative light scattering detector (ELSD). ELSD response to kanamycins was found to be enhanced by: (a) decrease of peak width and asymmetry (obtained by controlling the mobile phase acidity or ratio of organic solvent to water), (b) use of ion-pairing acidic reagents of increased molecular mass, and (c) increase of mobile phase volatility. Utilizing an Spherisorb ODS-2 C18 column, the selected optimized mobile phase was waterâacetonitrile (60:40, v/v), containing 11.6mM heptafluorobutyric acid (isocratic elution with flow rate of 1.0mlminâ1). Kanamycin A was eluted at 3.9min and kanamycin B at 5.0min with a resolution of 2.7. Logarithmic calibration curves were obtained from 0.6 to 28ÎŒgmlâ1 ( r>0.9998) for kanamycin A and 4â36ÎŒgmlâ1 ( r>0.9994) for kanamycin B, with a LOD equal to 0.20 and 1.4ÎŒgmlâ1, respectively.In kanamycin acid sulfate pharmaceutical raw materials, the simultaneous determination of sulfate ( tR=2.1min, LOD=2.3ÎŒgmlâ1, %R.S.D.=1.7, r>0.9998) and kanamycins was feasible. No significant difference ( t-test) was found between the results of the developed LCâELSD method and those of reference methods, while recovery from kanamycin B spiked samples ranged from 95 to 105%. The developed method was also applied with very good accuracy for the determination of kanamycin A in veterinary formulation (%recovery 95â103, %R.S.D.<1.4, n=3) and for the determination of kanamycins A and B in bacteria culture media (%recovery 102 and 99, respectively).
Keywords: Evaporative light scattering; ELSD; Kanamycin; LC; Sulfate; Aminoglycosides; Pharmaceuticals; Bacteria culture media
Direct determination of kanamycin in raw materials, veterinary formulation and culture media using a novel liquid chromatographyâevaporative light scattering method by N.C. Megoulas; M.A. Koupparis (pp. 64-72).
A novel method for the direct determination of kanamycin A and its minor component kanamycin B was developed and validated based on reversed phase liquid chromatography with evaporative light scattering detector (ELSD). ELSD response to kanamycins was found to be enhanced by: (a) decrease of peak width and asymmetry (obtained by controlling the mobile phase acidity or ratio of organic solvent to water), (b) use of ion-pairing acidic reagents of increased molecular mass, and (c) increase of mobile phase volatility. Utilizing an Spherisorb ODS-2 C18 column, the selected optimized mobile phase was waterâacetonitrile (60:40, v/v), containing 11.6mM heptafluorobutyric acid (isocratic elution with flow rate of 1.0mlminâ1). Kanamycin A was eluted at 3.9min and kanamycin B at 5.0min with a resolution of 2.7. Logarithmic calibration curves were obtained from 0.6 to 28ÎŒgmlâ1 ( r>0.9998) for kanamycin A and 4â36ÎŒgmlâ1 ( r>0.9994) for kanamycin B, with a LOD equal to 0.20 and 1.4ÎŒgmlâ1, respectively.In kanamycin acid sulfate pharmaceutical raw materials, the simultaneous determination of sulfate ( tR=2.1min, LOD=2.3ÎŒgmlâ1, %R.S.D.=1.7, r>0.9998) and kanamycins was feasible. No significant difference ( t-test) was found between the results of the developed LCâELSD method and those of reference methods, while recovery from kanamycin B spiked samples ranged from 95 to 105%. The developed method was also applied with very good accuracy for the determination of kanamycin A in veterinary formulation (%recovery 95â103, %R.S.D.<1.4, n=3) and for the determination of kanamycins A and B in bacteria culture media (%recovery 102 and 99, respectively).
Keywords: Evaporative light scattering; ELSD; Kanamycin; LC; Sulfate; Aminoglycosides; Pharmaceuticals; Bacteria culture media
Rapid, simple and accurate liquid chromatographyâdiode array detection validated method for the determination of dipyrone in solid and liquid dosage forms by Hamide Z. Senyuva; Inci Aksahin; Sureyya Ozcan; Burak Veli Kabasakal (pp. 73-77).
The goal of this study was to develop and validate a liquid chromatography (LC) method for the rapid determination of dipyrone (metamizole sodium) in solid and liquid formulations. Samples were extracted with water and filtered prior to LC analysis. The analytical procedure involved reversed phase LC with a Zorbax SB C18 column (5ÎŒm particle size, 4.6mmĂ250mm i.d.), isoctratic methanol/water (80/20, v/v) mobile phase with UV detection at 254nm. The flow rate was 1mLminâ1, injection volume was 100ÎŒL and retention time of dipyrone was 3.3min. The method was validated with respect to linearity, precision and accuracy. Calibration curves were linear in the range 0.5â100ÎŒgmLâ1 for analyte and the recoveries at three levels (10, 15 and 25ÎŒgmLâ1) ranged from 93 to 100%. All results for dipyrone were confirmed by liquid chromatographyâmass spectrometry (LCâMS) and1H nuclear magnetic resonance (NMR) spectroscopy. Due to its simplicity and accuracy, the assay method is suitable for routine analysis of both solid and liquid formulations and seven retail samples were analyzed using the validated method.
Keywords: Dipyrone; LC; Validation; LCâMS; NMR
Rapid, simple and accurate liquid chromatographyâdiode array detection validated method for the determination of dipyrone in solid and liquid dosage forms by Hamide Z. Senyuva; Inci Aksahin; Sureyya Ozcan; Burak Veli Kabasakal (pp. 73-77).
The goal of this study was to develop and validate a liquid chromatography (LC) method for the rapid determination of dipyrone (metamizole sodium) in solid and liquid formulations. Samples were extracted with water and filtered prior to LC analysis. The analytical procedure involved reversed phase LC with a Zorbax SB C18 column (5ÎŒm particle size, 4.6mmĂ250mm i.d.), isoctratic methanol/water (80/20, v/v) mobile phase with UV detection at 254nm. The flow rate was 1mLminâ1, injection volume was 100ÎŒL and retention time of dipyrone was 3.3min. The method was validated with respect to linearity, precision and accuracy. Calibration curves were linear in the range 0.5â100ÎŒgmLâ1 for analyte and the recoveries at three levels (10, 15 and 25ÎŒgmLâ1) ranged from 93 to 100%. All results for dipyrone were confirmed by liquid chromatographyâmass spectrometry (LCâMS) and1H nuclear magnetic resonance (NMR) spectroscopy. Due to its simplicity and accuracy, the assay method is suitable for routine analysis of both solid and liquid formulations and seven retail samples were analyzed using the validated method.
Keywords: Dipyrone; LC; Validation; LCâMS; NMR
The size exclusion chromatography calibration of âMixed-Aâ and âMixed-Dâ columns using various polymers and compounds: An application to coal-derived materials by Fatma Karaca; Marcos Millan; Mahtab Behrouzi; Alan A. Herod; Rafael Kandiyoti (pp. 78-82).
This work attempts to obtain the calibration curves of two different size exclusion chromatography (SEC) columns operating with 1-methyl-2-pyrrolidinone (NMP) as eluent by using various standards. Polystyrene (PS) and polymethylmethacrylate (PMMA) standards were used for obtaining calibration curves, and checked against polysaccharide (PSAC) standards, some small aromatic polycyclic standards and miscellaneous polymers. Polystyrenes and polymethylmethacrylates gave identical calibrations while polysaccharides and miscellaneous polymers lay within 1 or 2min of the polystyrene calibration. Small molecules of mass less than 1000units lay on or near to the polystyrene calibration lines, with a shift to late elution for the smallest molecules. This shift may be caused by the interaction with the column packing. A sample has been examined by analytical size exclusion chromatography, which was calibrated using polystyrene and polymethylmethacrylate standards. Molecular mass (MM) distributions of the sample have been examined in terms of these calibrations.
Keywords: Size exclusion chromatography; Calibration; Coal-derived materials
The size exclusion chromatography calibration of âMixed-Aâ and âMixed-Dâ columns using various polymers and compounds: An application to coal-derived materials by Fatma Karaca; Marcos Millan; Mahtab Behrouzi; Alan A. Herod; Rafael Kandiyoti (pp. 78-82).
This work attempts to obtain the calibration curves of two different size exclusion chromatography (SEC) columns operating with 1-methyl-2-pyrrolidinone (NMP) as eluent by using various standards. Polystyrene (PS) and polymethylmethacrylate (PMMA) standards were used for obtaining calibration curves, and checked against polysaccharide (PSAC) standards, some small aromatic polycyclic standards and miscellaneous polymers. Polystyrenes and polymethylmethacrylates gave identical calibrations while polysaccharides and miscellaneous polymers lay within 1 or 2min of the polystyrene calibration. Small molecules of mass less than 1000units lay on or near to the polystyrene calibration lines, with a shift to late elution for the smallest molecules. This shift may be caused by the interaction with the column packing. A sample has been examined by analytical size exclusion chromatography, which was calibrated using polystyrene and polymethylmethacrylate standards. Molecular mass (MM) distributions of the sample have been examined in terms of these calibrations.
Keywords: Size exclusion chromatography; Calibration; Coal-derived materials
Determination of sertaconazole in pharmaceutical preparations by capillary zone electrophoresis by Emirhan Nemutlu; Ceren Yardımcı; Nuran Ăzaltın (pp. 83-88).
A capillary electrophoresis assay for the analysis of sertaconazole has been developed and validated. The influence of buffer concentration, buffer pH, organic modifier, capillary temperature, applied voltage and injection time was systemically investigated in a fused silica capillary (i.d. 50Όm, total length 80.5cm and effective length 72.0cm). Optimum results were obtained with a 20mM phosphate buffer (pH 4.0) containing 40% acetonitrile, capillary temperature 30°C, applied voltage 30kV and 3s hydrodynamic injection at 50mbar. The detection wavelength was set to 205nm. Verapamil was used as internal standard. The method showed good selectivity, repeatability, linearity and sensitivity according to the evaluation of the validation parameters. The method was applied to the determination of sertaconazole in pharmaceutical cream formulations.
Keywords: Sertaconazole; Capillary zone electrophoresis; Validation; Pharmaceuticals
Determination of sertaconazole in pharmaceutical preparations by capillary zone electrophoresis by Emirhan Nemutlu; Ceren Yardımcı; Nuran Ăzaltın (pp. 83-88).
A capillary electrophoresis assay for the analysis of sertaconazole has been developed and validated. The influence of buffer concentration, buffer pH, organic modifier, capillary temperature, applied voltage and injection time was systemically investigated in a fused silica capillary (i.d. 50Όm, total length 80.5cm and effective length 72.0cm). Optimum results were obtained with a 20mM phosphate buffer (pH 4.0) containing 40% acetonitrile, capillary temperature 30°C, applied voltage 30kV and 3s hydrodynamic injection at 50mbar. The detection wavelength was set to 205nm. Verapamil was used as internal standard. The method showed good selectivity, repeatability, linearity and sensitivity according to the evaluation of the validation parameters. The method was applied to the determination of sertaconazole in pharmaceutical cream formulations.
Keywords: Sertaconazole; Capillary zone electrophoresis; Validation; Pharmaceuticals
Gas chromatographic separation of PCB and OCP by photocatalytic degradation by S. Meral Karakartal; S. Fatma Aygün; A. Nur Onar (pp. 89-93).
A photocatalytic degradation method was developed for polychlorobiphenyl (PCB) and organochloride pesticide (OCP) discrimination and quantification. A mixture of Aroclor 1260 and p, pâČ-DDT was irradiated at 254nm by UV lamp (40W) in the presence of TiO2 (30mgmLâ1 non-aqueous solution). Comparison of gas chromatograms showed that p, pâČ-DDT signals decreased significantly after irradiation, while Aroclor 1260s chromatograms did not show any difference before and after irradiation. Detection limits were 0.30mgLâ1 and 0.15mgLâ1 for p, pâČ-DDT and Aroclor 1260, respectively. The method was applied to spiked egg samples, the recoveries were found as 72% for DDT and 82.01% for Aroclor 1260.
Keywords: Polychlorobiphenyls; Organochloride pesticides; TiO; 2; Photocatalytic degradation
Gas chromatographic separation of PCB and OCP by photocatalytic degradation by S. Meral Karakartal; S. Fatma AygĂŒn; A. Nur Onar (pp. 89-93).
A photocatalytic degradation method was developed for polychlorobiphenyl (PCB) and organochloride pesticide (OCP) discrimination and quantification. A mixture of Aroclor 1260 and p, pâČ-DDT was irradiated at 254nm by UV lamp (40W) in the presence of TiO2 (30mgmLâ1 non-aqueous solution). Comparison of gas chromatograms showed that p, pâČ-DDT signals decreased significantly after irradiation, while Aroclor 1260s chromatograms did not show any difference before and after irradiation. Detection limits were 0.30mgLâ1 and 0.15mgLâ1 for p, pâČ-DDT and Aroclor 1260, respectively. The method was applied to spiked egg samples, the recoveries were found as 72% for DDT and 82.01% for Aroclor 1260.
Keywords: Polychlorobiphenyls; Organochloride pesticides; TiO; 2; Photocatalytic degradation
Prediction of molecular weight and density of n-alkanes (C6âC44) by Hilal Gürbüz Yücel (pp. 94-97).
Heavy n-alkanes and their mixtures were characterized by high temperature-simulated distillation using gas chromatography with a capillary column. In this work, the atmospheric boiling point is determined by the HT-SimDis GC method. In this study, molecular weights and density of n-alkanes were evaluated with this method by using retention times and normal boiling points as input data. ASTM D2887 calibration mixture containing 17 n-alkanes in the C6âC44 range were used for qualitative analyses. Retention times ( tR) of n-alkanes were measured with this method. The other input data that normal boiling points ( Tb) and molecular weight ( M) had been taken in the literature. Experimental densities (at 20°C) of n-alkanes were obtained from API Research Projects. Empirical molecular weight and density correlations were developed by using the nonlinear and multiple regressions with correlation coefficients. The results of calculations were compared with experimental data. Normal boiling point predictions were obtained as an average absolute deviation of 1.07%. Molecular weight and density results were evaluated as average absolute deviations of 0.68% and 0.21%, respectively.
Keywords: n; -Alkanes; n; -Paraffins; HT-SimDis GC; Wax; Molecular weight; Density
Prediction of molecular weight and density of n-alkanes (C6âC44) by Hilal GĂŒrbĂŒz YĂŒcel (pp. 94-97).
Heavy n-alkanes and their mixtures were characterized by high temperature-simulated distillation using gas chromatography with a capillary column. In this work, the atmospheric boiling point is determined by the HT-SimDis GC method. In this study, molecular weights and density of n-alkanes were evaluated with this method by using retention times and normal boiling points as input data. ASTM D2887 calibration mixture containing 17 n-alkanes in the C6âC44 range were used for qualitative analyses. Retention times ( tR) of n-alkanes were measured with this method. The other input data that normal boiling points ( Tb) and molecular weight ( M) had been taken in the literature. Experimental densities (at 20°C) of n-alkanes were obtained from API Research Projects. Empirical molecular weight and density correlations were developed by using the nonlinear and multiple regressions with correlation coefficients. The results of calculations were compared with experimental data. Normal boiling point predictions were obtained as an average absolute deviation of 1.07%. Molecular weight and density results were evaluated as average absolute deviations of 0.68% and 0.21%, respectively.
Keywords: n; -Alkanes; n; -Paraffins; HT-SimDis GC; Wax; Molecular weight; Density
Normal spectrophotometric and stopped-flow spectrofluorimetric sequential injection methods for the determination of alendronic acid, an anti-osteoporosis amino-bisphosphonate drug, in pharmaceuticals by Paraskevas D. Tzanavaras; Constantinos K. Zacharis; Georgios A. Theodoridis; Eftichios A. Kalaitzantonakis; Anastasios N. Voulgaropoulos (pp. 98-103).
A normal spectrophotometric and a stopped-flow (SF) spectrofluorimetric method have been developed and optimized for the determination of alendronic acid (ALD) in its pharmaceutical formulations. Both methods are automated using the sequential injection analysis (SIA) principle. The spectrophotometric assay is based on the reaction of the analyte with Cu(II) ions in acidic medium to form an UV-absorbing derivative ( λmax=240nm). The SF spectrofluorimetric method is based on the reaction of ALD with o-phthalaldehyde (OPA) in the presence of 2-mercaptoethanol at basic medium ( λex=340nm/ λem=455nm). Linear calibration curves were obtained in the range 1.0â60.0mglâ1 ALD for the UV method, and in the range 0.13â10.0mglâ1 ALD for the SF spectrofluorimetric one. The sampling rates were 60 and 30hâ1, respectively. The developed assays are critically compared and their advantages are discussed. Both methods were applied to the analysis of an ALD containing pharmaceutical formulation with satisfactory accuracy and precision.
Keywords: Alendronic acid; Sequential injection; UV-spectrophotometry; Stopped-flow spectrofluorimetry; Pharmaceutical analysis
Normal spectrophotometric and stopped-flow spectrofluorimetric sequential injection methods for the determination of alendronic acid, an anti-osteoporosis amino-bisphosphonate drug, in pharmaceuticals by Paraskevas D. Tzanavaras; Constantinos K. Zacharis; Georgios A. Theodoridis; Eftichios A. Kalaitzantonakis; Anastasios N. Voulgaropoulos (pp. 98-103).
A normal spectrophotometric and a stopped-flow (SF) spectrofluorimetric method have been developed and optimized for the determination of alendronic acid (ALD) in its pharmaceutical formulations. Both methods are automated using the sequential injection analysis (SIA) principle. The spectrophotometric assay is based on the reaction of the analyte with Cu(II) ions in acidic medium to form an UV-absorbing derivative ( λmax=240nm). The SF spectrofluorimetric method is based on the reaction of ALD with o-phthalaldehyde (OPA) in the presence of 2-mercaptoethanol at basic medium ( λex=340nm/ λem=455nm). Linear calibration curves were obtained in the range 1.0â60.0mglâ1 ALD for the UV method, and in the range 0.13â10.0mglâ1 ALD for the SF spectrofluorimetric one. The sampling rates were 60 and 30hâ1, respectively. The developed assays are critically compared and their advantages are discussed. Both methods were applied to the analysis of an ALD containing pharmaceutical formulation with satisfactory accuracy and precision.
Keywords: Alendronic acid; Sequential injection; UV-spectrophotometry; Stopped-flow spectrofluorimetry; Pharmaceutical analysis
Flow injection fluorescence determination of dopamine using a photo induced electron transfer (PET) boronic acid derivative by Z. Ebru Seçkin; Mürvet Volkan (pp. 104-108).
An automated flow injection analysis system was developed for the fluorometric determination of dopamine in pharmaceutical injections. The method is based on the quenching effect of dopamine on m-dansylaminophenyl boronic acid (DAPB) fluorescence due to the reverse photo induced electron transfer (PET) mechanism. Effects of pH and interfering species on the determination of dopamine were examined. Calibration for dopamine, based on quenching data, was linear in the concentration range of 1.0Ă10â5 to 1.0Ă10â4M. Detection limit (3s) of the method was found to be 3.7Ă10â6M. Relative standard deviation of 1.2% ( n=10) was obtained with 1.0Ă10â5M dopamine standard solution. The proposed method was applied successfully for the determination of dopamine in pharmaceutical injection sample. The sampling rate was determined as 24 samples per hour.
Keywords: Flow injection analysis (FIA); Photo induced electron transfer (PET); Spectrofluorometry; Boronic acid; Dopamine; Injection
Flow injection fluorescence determination of dopamine using a photo induced electron transfer (PET) boronic acid derivative by Z. Ebru Seçkin; MĂŒrvet Volkan (pp. 104-108).
An automated flow injection analysis system was developed for the fluorometric determination of dopamine in pharmaceutical injections. The method is based on the quenching effect of dopamine on m-dansylaminophenyl boronic acid (DAPB) fluorescence due to the reverse photo induced electron transfer (PET) mechanism. Effects of pH and interfering species on the determination of dopamine were examined. Calibration for dopamine, based on quenching data, was linear in the concentration range of 1.0Ă10â5 to 1.0Ă10â4M. Detection limit (3s) of the method was found to be 3.7Ă10â6M. Relative standard deviation of 1.2% ( n=10) was obtained with 1.0Ă10â5M dopamine standard solution. The proposed method was applied successfully for the determination of dopamine in pharmaceutical injection sample. The sampling rate was determined as 24 samples per hour.
Keywords: Flow injection analysis (FIA); Photo induced electron transfer (PET); Spectrofluorometry; Boronic acid; Dopamine; Injection
Determination of arsenic species in seafood samples from the Aegean Sea by liquid chromatographyâ(photo-oxidation)âhydride generationâatomic fluorescence spectrometry by Richard Schaeffer; Csilla Soeroes; Ildiko Ipolyi; Peter Fodor; Nikolaos S. Thomaidis (pp. 109-118).
In this study arsenic compounds were determined in mussels ( Mytulis galloprovincialis), anchovies ( Engraulis encrasicholus), sea-breams ( Sparus aurata), sea bass ( Dicentrarchus labrax) and sardines ( Sardina pilchardus) collected from Aegean Sea using liquid chromatographyâphoto-oxidationâhydride generationâatomic fluorescence spectrometry [LCâ(PO)âHGâAFS] system. Twelve arsenicals were separated and determined on the basis of their difference in two properties: (i) the p Ka values and (ii) hydride generation capacity. The separation was carried out both with an anion- and a cation-exchange column, with and without photo-oxidation. In all the samples arsenobetaine, AB was detected as the major compound (concentrations ranging between 2.7 and 23.1ÎŒggâ1 dry weight), with trace amounts of arsenite, As(III), dimethylarsinic acid, DMA and arsenocholine, AC, also present. Arsenosugars were detected only in the mussel samples (in concentrations of 0.9â3.6ÎŒggâ1 dry weight), along with the presence of an unknown compound, which, based on its retention time on the anion-exchange column Hamilton PRP-X100 and a recent communication [E. Schmeisser, R. Raml, K.A. Francesconi, D. Kuehnelt, A. Lindberg, Cs. Soeroes, W. Goessler, Chem. Commun. 16 (2004) 1824], is supposed to be a thio-arsenic analogue.
Keywords: Arsenic speciation; Marine samples; Water extraction; Hydride generation; Atomic fluorescence spectrometry; Liquid chromatography
Determination of arsenic species in seafood samples from the Aegean Sea by liquid chromatographyâ(photo-oxidation)âhydride generationâatomic fluorescence spectrometry by Richard Schaeffer; Csilla Soeroes; Ildiko Ipolyi; Peter Fodor; Nikolaos S. Thomaidis (pp. 109-118).
In this study arsenic compounds were determined in mussels ( Mytulis galloprovincialis), anchovies ( Engraulis encrasicholus), sea-breams ( Sparus aurata), sea bass ( Dicentrarchus labrax) and sardines ( Sardina pilchardus) collected from Aegean Sea using liquid chromatographyâphoto-oxidationâhydride generationâatomic fluorescence spectrometry [LCâ(PO)âHGâAFS] system. Twelve arsenicals were separated and determined on the basis of their difference in two properties: (i) the p Ka values and (ii) hydride generation capacity. The separation was carried out both with an anion- and a cation-exchange column, with and without photo-oxidation. In all the samples arsenobetaine, AB was detected as the major compound (concentrations ranging between 2.7 and 23.1ÎŒggâ1 dry weight), with trace amounts of arsenite, As(III), dimethylarsinic acid, DMA and arsenocholine, AC, also present. Arsenosugars were detected only in the mussel samples (in concentrations of 0.9â3.6ÎŒggâ1 dry weight), along with the presence of an unknown compound, which, based on its retention time on the anion-exchange column Hamilton PRP-X100 and a recent communication [E. Schmeisser, R. Raml, K.A. Francesconi, D. Kuehnelt, A. Lindberg, Cs. Soeroes, W. Goessler, Chem. Commun. 16 (2004) 1824], is supposed to be a thio-arsenic analogue.
Keywords: Arsenic speciation; Marine samples; Water extraction; Hydride generation; Atomic fluorescence spectrometry; Liquid chromatography
Influence of acid mining activity on release of aluminium to the environment by Jana KubovĂĄ; Peter MatĂșĆĄ; Marek BujdoĆĄ; JĂĄn Medvedâ (pp. 119-125).
An optimized BCR three-step sequential extraction procedure, several single extractions and the reactive aluminium determination after chelating ion-exchange on Iontosorb Salicyl were used for the fractionation of Al in soil samples from a mining area with sulphidic deposits. The aluminium amounts released by used extraction procedures were valuated and discussed. The new indicative values of fractional Al concentrations in five Chinese certified reference materials (GBW 07103, 07304, 07401, 07405, 07407) were determined after Al fractionation by optimized BCR three-step sequential extraction procedure. The aluminium toxicity indexes calculated for two different soil extracts and plant samples were used for assessment of Al toxicity to plants. It can be concluded that the most sensitive indicator of increasing aluminium toxicity to plants is determination of reactive Al species in soil solution by chelating ion-exchange solid phase extraction.The atomic absorption spectrometry with nitrous oxide-acetylene flame was used for determination of total Al amounts and the Al concentration in different extraction fractions as well.
Keywords: Fractionation; Single and sequential extraction; Ion-exchange; Solid phase extraction; Reactive aluminium; Aluminium toxicity index (ATI)
Influence of acid mining activity on release of aluminium to the environment by Jana KubovĂĄ; Peter MatĂșĆĄ; Marek BujdoĆĄ; JĂĄn Medvedâ (pp. 119-125).
An optimized BCR three-step sequential extraction procedure, several single extractions and the reactive aluminium determination after chelating ion-exchange on Iontosorb Salicyl were used for the fractionation of Al in soil samples from a mining area with sulphidic deposits. The aluminium amounts released by used extraction procedures were valuated and discussed. The new indicative values of fractional Al concentrations in five Chinese certified reference materials (GBW 07103, 07304, 07401, 07405, 07407) were determined after Al fractionation by optimized BCR three-step sequential extraction procedure. The aluminium toxicity indexes calculated for two different soil extracts and plant samples were used for assessment of Al toxicity to plants. It can be concluded that the most sensitive indicator of increasing aluminium toxicity to plants is determination of reactive Al species in soil solution by chelating ion-exchange solid phase extraction.The atomic absorption spectrometry with nitrous oxide-acetylene flame was used for determination of total Al amounts and the Al concentration in different extraction fractions as well.
Keywords: Fractionation; Single and sequential extraction; Ion-exchange; Solid phase extraction; Reactive aluminium; Aluminium toxicity index (ATI)
Effect of nitric acid for equal stabilization and sensitivity of different selenium species in electrothermal atomic absorption spectrometry by Feyime Ćahin; MĂŒrvet Volkan; O. Yavuz Ataman (pp. 126-131).
Determination of selenium by electrothermal atomic absorption spectrometry (ETAAS) is complicated by the presence of different species of this analyte. The presence of different oxidation states (âII, IV and VI) may result in different sensitivities obtained for each species rendering impossible the use of a single species for calibration. These species also exhibit different behaviours regarding thermal stabilities; the temperature program must be provided to conform to this problem. Chemical modifiers are commonly used for thermal stabilization of selenium species. In this study, experiments were carried out to demonstrate the effect of nitric acid in the presence of chemical modifiers. Nickel and palladium+magnesium were selected as the most commonly used chemical modifiers. Using both aqueous and human serum solutions it has been demonstrated that although chemical modifiers provide thermal stabilization of species so that higher ashing temperatures can be used, equal sensitivities cannot be achieved unless nitric acid is also present. Selenite, selenate, selenomethionine and selenocystine were used in experiments. When equal sensitivities for all these species are achieved, determination of total selenium by ETAAS can be performed by using a single species as the standard; selenite was used in this study. Precision was 5.0% or better using peak height signals. There was no significant difference in detection limits (3s) when Ni or Pd+Mg(NO3)2 was used as chemical modifier; 37 and 35pg of selenium were found to be the detection limits for Ni and Pd+Mg(NO3)2 chemical modifiers, respectively. For chemical modifications, either 5ÎŒg of Ni or 0.5ÎŒg of Pd and 5ÎŒg of Mg(NO3)2 were used; final solutions contained 2.5% HNO3. In serum analyses, 10ÎŒg of Ni was used in presence of 2.5% HNO3.
Keywords: Selenite; Selenate; Selenomethionine; Selenocystine; Serum; Electrothermal atomic absorption spectrometry; Chemical modifiers
Effect of nitric acid for equal stabilization and sensitivity of different selenium species in electrothermal atomic absorption spectrometry by Feyime Ćahin; MĂŒrvet Volkan; O. Yavuz Ataman (pp. 126-131).
Determination of selenium by electrothermal atomic absorption spectrometry (ETAAS) is complicated by the presence of different species of this analyte. The presence of different oxidation states (âII, IV and VI) may result in different sensitivities obtained for each species rendering impossible the use of a single species for calibration. These species also exhibit different behaviours regarding thermal stabilities; the temperature program must be provided to conform to this problem. Chemical modifiers are commonly used for thermal stabilization of selenium species. In this study, experiments were carried out to demonstrate the effect of nitric acid in the presence of chemical modifiers. Nickel and palladium+magnesium were selected as the most commonly used chemical modifiers. Using both aqueous and human serum solutions it has been demonstrated that although chemical modifiers provide thermal stabilization of species so that higher ashing temperatures can be used, equal sensitivities cannot be achieved unless nitric acid is also present. Selenite, selenate, selenomethionine and selenocystine were used in experiments. When equal sensitivities for all these species are achieved, determination of total selenium by ETAAS can be performed by using a single species as the standard; selenite was used in this study. Precision was 5.0% or better using peak height signals. There was no significant difference in detection limits (3s) when Ni or Pd+Mg(NO3)2 was used as chemical modifier; 37 and 35pg of selenium were found to be the detection limits for Ni and Pd+Mg(NO3)2 chemical modifiers, respectively. For chemical modifications, either 5ÎŒg of Ni or 0.5ÎŒg of Pd and 5ÎŒg of Mg(NO3)2 were used; final solutions contained 2.5% HNO3. In serum analyses, 10ÎŒg of Ni was used in presence of 2.5% HNO3.
Keywords: Selenite; Selenate; Selenomethionine; Selenocystine; Serum; Electrothermal atomic absorption spectrometry; Chemical modifiers
Determination of selenium in human milk by electrothermal atomic absorption spectrometry and chemical modification by Stavroula Theodorolea; Nikolaos S. Thomaidis; Efrosini Piperaki (pp. 132-137).
A method was developed for the determination of selenium in human milk using electrothermal atomic absorption spectrometry. The use of chemical modifiers as well as their implications during the pyrolysis step was examined. The chemical modifiers that were studied were Zr, Ir as well as the mixed modifier ZrâIr. The Ir modifier stabilized selenium at 1000°C, Zr at 800°C, while the mixed modifier at 1200°C. The effect of modifier mass was studied and was found that better results are achieved with addition of 2ÎŒg Zr and 2ÎŒg Ir. The characteristic masses of selenium in the presence of Zr, Ir and the mixed modifier were found to be 73.3, 18.0 and 14.7pg, respectively, while the corresponding limits of detection were found 2.0, 0.50 and 0.41ÎŒglâ1. Consequently better results were obtained with the mixed modifier. The developed method was applied for the determination of selenium in human milk, which was digested with a HNO3+H2O2 mixture in a microwave oven. The limit of detection of the method was 1.37ÎŒglâ1, the characteristic mass, m0, was 48.8pg and the repeatability was less than 5% as R.S.D.(%). Matrix matched calibration was used. Recoveries were estimated to be 93â105%. The method was applied to breast milk of Greek women ( n=9) and the Se content was found to be in the range 16.7â42.6ÎŒglâ1 with mean value 27.4±5.5ÎŒglâ1.
Keywords: Selenium; Human milk; Iridium; Zirconium; Chemical modifiers; ETAAS
Determination of selenium in human milk by electrothermal atomic absorption spectrometry and chemical modification by Stavroula Theodorolea; Nikolaos S. Thomaidis; Efrosini Piperaki (pp. 132-137).
A method was developed for the determination of selenium in human milk using electrothermal atomic absorption spectrometry. The use of chemical modifiers as well as their implications during the pyrolysis step was examined. The chemical modifiers that were studied were Zr, Ir as well as the mixed modifier ZrâIr. The Ir modifier stabilized selenium at 1000°C, Zr at 800°C, while the mixed modifier at 1200°C. The effect of modifier mass was studied and was found that better results are achieved with addition of 2ÎŒg Zr and 2ÎŒg Ir. The characteristic masses of selenium in the presence of Zr, Ir and the mixed modifier were found to be 73.3, 18.0 and 14.7pg, respectively, while the corresponding limits of detection were found 2.0, 0.50 and 0.41ÎŒglâ1. Consequently better results were obtained with the mixed modifier. The developed method was applied for the determination of selenium in human milk, which was digested with a HNO3+H2O2 mixture in a microwave oven. The limit of detection of the method was 1.37ÎŒglâ1, the characteristic mass, m0, was 48.8pg and the repeatability was less than 5% as R.S.D.(%). Matrix matched calibration was used. Recoveries were estimated to be 93â105%. The method was applied to breast milk of Greek women ( n=9) and the Se content was found to be in the range 16.7â42.6ÎŒglâ1 with mean value 27.4±5.5ÎŒglâ1.
Keywords: Selenium; Human milk; Iridium; Zirconium; Chemical modifiers; ETAAS
Determination of bismuth and zinc in pharmaceuticals by first derivative UVâVisible spectrophotometry by G. Gumus; H. Filik; B. Demirata (pp. 138-143).
A first order derivative spectrophotometric method has been developed for the simultaneous determination of bismuth and zinc by dithizone without time-consuming extraction step. The reactions of bismuth and zinc with dithizone in a three component solution prepared in water, acetone and n-propanol mixture have been investigated. These cations react with dithizone in this mixture at pH 5.0, forming coloured complex that is stable for at least 2h. The linear range in D evaluation was between 3.0Ă10â6 and 1.8Ă10â5mollâ1 for Zn and 2.4Ă10â6 and 1.2Ă10â5mollâ1 for Bi. The limits of detection for the analytical procedure were found 0.05mglâ1 for both cations. The relative standard deviations for the determination of 0.5mglâ1 bismuth and 0.5mglâ1 zinc were 1.2 and 1.1%, respectively, for five determinations. The procedure is simple, rapid and reliable. This method was applied to the determination of bismuth and zinc in the pharmaceutical materials successfully. Good agreement was achieved between the results obtained by the proposed and comparative methods.
Keywords: Bismuth; Zinc; Determination; Pharmaceuticals; Derivative spectrophotometry; Microwave digestion
Determination of bismuth and zinc in pharmaceuticals by first derivative UVâVisible spectrophotometry by G. Gumus; H. Filik; B. Demirata (pp. 138-143).
A first order derivative spectrophotometric method has been developed for the simultaneous determination of bismuth and zinc by dithizone without time-consuming extraction step. The reactions of bismuth and zinc with dithizone in a three component solution prepared in water, acetone and n-propanol mixture have been investigated. These cations react with dithizone in this mixture at pH 5.0, forming coloured complex that is stable for at least 2h. The linear range in D evaluation was between 3.0Ă10â6 and 1.8Ă10â5mollâ1 for Zn and 2.4Ă10â6 and 1.2Ă10â5mollâ1 for Bi. The limits of detection for the analytical procedure were found 0.05mglâ1 for both cations. The relative standard deviations for the determination of 0.5mglâ1 bismuth and 0.5mglâ1 zinc were 1.2 and 1.1%, respectively, for five determinations. The procedure is simple, rapid and reliable. This method was applied to the determination of bismuth and zinc in the pharmaceutical materials successfully. Good agreement was achieved between the results obtained by the proposed and comparative methods.
Keywords: Bismuth; Zinc; Determination; Pharmaceuticals; Derivative spectrophotometry; Microwave digestion
Kinetic spectrophotometric method for gold(III) determination by Sofija M. Rancic; Snezana D. Nikolic-Mandic; Ljuba M. Mandic (pp. 144-149).
The kinetic spectrophotometric method for Au(III) determination was developed and validated. It was based on the catalytic effect of gold on the oxidation of methylene blue B (3,7di-(dimethyl amino)-10-dehydro-phenotiazin chloride) by ammonium peroxo-disulfate in citric buffer solution. There was the linearity of the calibration curve in the concentration range from 0.09 to 2.90ÎŒgmlâ1 Au(III). The relative standard deviation was 2.50% and correlation coefficient of 0.9999. The limit of detection was determined as signal to noise ratio (3:1) and it was 5.5ngmlâ1. The limit of quantification, based on signal to noise ratio 10:1 was 19.25ngmlâ1. The selectivity was tested on the basis of influence of known amounts of different ions in the reaction mixture, upon the reaction rate. Kinetic and thermodynamic parameters were reported for both catalytic and non-catalytic reactions. The method was verified by Au(III) determination in anti-rheumatic drug âTauredonâ? and in human urine samples, using ICPâAES as the comparative method. As the method is accurate, reliable, quick and simple it could be useful for clinical and toxicological practice.
Keywords: Gold(III); Spectrophotometric kinetic method; Anti-rheumatic drug; Urine
Kinetic spectrophotometric method for gold(III) determination by Sofija M. Rancic; Snezana D. Nikolic-Mandic; Ljuba M. Mandic (pp. 144-149).
The kinetic spectrophotometric method for Au(III) determination was developed and validated. It was based on the catalytic effect of gold on the oxidation of methylene blue B (3,7di-(dimethyl amino)-10-dehydro-phenotiazin chloride) by ammonium peroxo-disulfate in citric buffer solution. There was the linearity of the calibration curve in the concentration range from 0.09 to 2.90ÎŒgmlâ1 Au(III). The relative standard deviation was 2.50% and correlation coefficient of 0.9999. The limit of detection was determined as signal to noise ratio (3:1) and it was 5.5ngmlâ1. The limit of quantification, based on signal to noise ratio 10:1 was 19.25ngmlâ1. The selectivity was tested on the basis of influence of known amounts of different ions in the reaction mixture, upon the reaction rate. Kinetic and thermodynamic parameters were reported for both catalytic and non-catalytic reactions. The method was verified by Au(III) determination in anti-rheumatic drug âTauredonâ and in human urine samples, using ICPâAES as the comparative method. As the method is accurate, reliable, quick and simple it could be useful for clinical and toxicological practice.
Keywords: Gold(III); Spectrophotometric kinetic method; Anti-rheumatic drug; Urine