A simple and reproducible method for the rapid extraction and determination of trace amounts of copper（Ⅱ） ions using octadecyl-bonded silica membrane disks modified by N,N′-disalicylideneethylenediamine （DESDA） ...A simple and reproducible method for the rapid extraction and determination of trace amounts of copper（Ⅱ） ions using octadecyl-bonded silica membrane disks modified by N,N′-disalicylideneethylenediamine （DESDA） and atomic absorption spectrometry was presented. The method is based on complex formation on the surface of the ENVI-18 DISK^TM disks followed by stripping of the retained species by minimum amounts of appropriate organic solvents. The elution is efficient and quantitative. The effects of potential interfering ions, pH, ligand amount, stripping solvent, and sample flow rate were also investigated. Under the optimal experimental conditions, the break-through volume was found to about be 1000 mL providing a preconcentration factor of 500. The maximum capacity of the disks was found to be （389±4） μg for Cu^2＋. The limit of detection of the proposed method is 5 ng per liter. The method was applied to the extraction and recovery of copper in different water samples.展开更多
A novel and selective method for the fast determination of trace amounts of chromium species in water samples has been developed. The procedure is based on the selective formation of chromium diethyldithiocarbamate co...A novel and selective method for the fast determination of trace amounts of chromium species in water samples has been developed. The procedure is based on the selective formation of chromium diethyldithiocarbamate complexes at different pH in the presence of Mn（Ⅱ） as an enhancement agent of chromium signals followed by elution with organic eluents and determination by atomic flame absorption spectrometry. The maximum capacity of the employed disks was found to be （396±3） pg and （376±2） pg for Cr（Ⅲ） and Cr（Ⅵ）, respectively. The detection limit of the proposed method is 49 and 43 ng·L^-1 for Cr（Ⅲ） and Cr（Ⅵ）, respectively. The proposed method was successfully applied for determination of chromium species Cr（Ⅲ） and Cr（Ⅵ） in different water samples.展开更多
A simple and reproducible method for the rapid extraction and determination of trace amounts of copper（Ⅱ） ions using octadecyl-bonded silica membrane disks modified by 1,5-diphenylcarbazide （DPC） and atomic absor...A simple and reproducible method for the rapid extraction and determination of trace amounts of copper（Ⅱ） ions using octadecyl-bonded silica membrane disks modified by 1,5-diphenylcarbazide （DPC） and atomic absorption spectrometry was presented, which was based on complex formation on the surface of the ENVI-18 DISK^TM disks followed by stripping of the retained species by minimum amounts of appropriate organic solvents. The elution was efficient and quantitative. The effect of potential interfering ions, pH, ligand amount, stripping solvent, and sample flow rate were also investigated. Under the optimal experimental conditions, the break-through volume was found to be about 1000 mL providing a preconcentration factor of 400. The maximum capacity of the disks was found to be （255±5） lag for Cu^2＋, and the limit of detection of the proposed method was 5 ng per 1000 mL. The method was applied to the extraction and recovery of copper in different water samples.展开更多
Silica gel-loaded （E）-N-（1-thien-2＇-ylethylidene）-1,2-phenylenediamine （TEPDA） phase was synthesized based on physical adsorption approaches. The stability of a chemically modified TEPDA especially in concentra...Silica gel-loaded （E）-N-（1-thien-2＇-ylethylidene）-1,2-phenylenediamine （TEPDA） phase was synthesized based on physical adsorption approaches. The stability of a chemically modified TEPDA especially in concentrated hydrochloric acid that was then used as a recycling and preconcentration reagent allowed the further uses of silica gel-loaded immobilized TEPDA phase. The application of this silica gel-loaded phase to sorption of a series of metal ions was performed by using different controlling factors such as the pH of the metal ion solution and the equilibration shaking time by the static technique. This difference was interpreted on the basis of selectivity incorporated in these sulfur containing silica gel-loaded TEPDA phases. Hg（Ⅱ） was found to exhibit the highest affinity towards extraction by these silica gel-loaded TEPDA phases. The pronounced selectivity was also confirmed by the determined distribution coefficients （Kd） of all the metal ions, showing the highest value reported for mercury（Ⅱ） extraction by the silica gel immobilized TEPDA phase. The potential applications of the silica gel immobilized TEPDA phase to selective extraction of mercury（Ⅱ） from aqueous solution were successfully accomplished and preconcentration of low concentration of Hg（Ⅱ） （30 pg·mL^-1） from natural tap water with a preconcentration factor of 200 for Hg（Ⅱ） off-line analysis was conducted by cold vapor atomic absorption analysis.展开更多
文摘A simple and reproducible method for the rapid extraction and determination of trace amounts of copper（Ⅱ） ions using octadecyl-bonded silica membrane disks modified by N,N′-disalicylideneethylenediamine （DESDA） and atomic absorption spectrometry was presented. The method is based on complex formation on the surface of the ENVI-18 DISK^TM disks followed by stripping of the retained species by minimum amounts of appropriate organic solvents. The elution is efficient and quantitative. The effects of potential interfering ions, pH, ligand amount, stripping solvent, and sample flow rate were also investigated. Under the optimal experimental conditions, the break-through volume was found to about be 1000 mL providing a preconcentration factor of 500. The maximum capacity of the disks was found to be （389±4） μg for Cu^2＋. The limit of detection of the proposed method is 5 ng per liter. The method was applied to the extraction and recovery of copper in different water samples.
文摘A novel and selective method for the fast determination of trace amounts of chromium species in water samples has been developed. The procedure is based on the selective formation of chromium diethyldithiocarbamate complexes at different pH in the presence of Mn（Ⅱ） as an enhancement agent of chromium signals followed by elution with organic eluents and determination by atomic flame absorption spectrometry. The maximum capacity of the employed disks was found to be （396±3） pg and （376±2） pg for Cr（Ⅲ） and Cr（Ⅵ）, respectively. The detection limit of the proposed method is 49 and 43 ng·L^-1 for Cr（Ⅲ） and Cr（Ⅵ）, respectively. The proposed method was successfully applied for determination of chromium species Cr（Ⅲ） and Cr（Ⅵ） in different water samples.
文摘A simple and reproducible method for the rapid extraction and determination of trace amounts of copper（Ⅱ） ions using octadecyl-bonded silica membrane disks modified by 1,5-diphenylcarbazide （DPC） and atomic absorption spectrometry was presented, which was based on complex formation on the surface of the ENVI-18 DISK^TM disks followed by stripping of the retained species by minimum amounts of appropriate organic solvents. The elution was efficient and quantitative. The effect of potential interfering ions, pH, ligand amount, stripping solvent, and sample flow rate were also investigated. Under the optimal experimental conditions, the break-through volume was found to be about 1000 mL providing a preconcentration factor of 400. The maximum capacity of the disks was found to be （255±5） lag for Cu^2＋, and the limit of detection of the proposed method was 5 ng per 1000 mL. The method was applied to the extraction and recovery of copper in different water samples.
基金Project supported by the National Natural Science Foundation of China （No. 20271025）, the Natural Science Foundation of Shandong Province （No. L2003B01） and the State Key Laboratory of Crystal Materials, Shandong University.
文摘Silica gel-loaded （E）-N-（1-thien-2＇-ylethylidene）-1,2-phenylenediamine （TEPDA） phase was synthesized based on physical adsorption approaches. The stability of a chemically modified TEPDA especially in concentrated hydrochloric acid that was then used as a recycling and preconcentration reagent allowed the further uses of silica gel-loaded immobilized TEPDA phase. The application of this silica gel-loaded phase to sorption of a series of metal ions was performed by using different controlling factors such as the pH of the metal ion solution and the equilibration shaking time by the static technique. This difference was interpreted on the basis of selectivity incorporated in these sulfur containing silica gel-loaded TEPDA phases. Hg（Ⅱ） was found to exhibit the highest affinity towards extraction by these silica gel-loaded TEPDA phases. The pronounced selectivity was also confirmed by the determined distribution coefficients （Kd） of all the metal ions, showing the highest value reported for mercury（Ⅱ） extraction by the silica gel immobilized TEPDA phase. The potential applications of the silica gel immobilized TEPDA phase to selective extraction of mercury（Ⅱ） from aqueous solution were successfully accomplished and preconcentration of low concentration of Hg（Ⅱ） （30 pg·mL^-1） from natural tap water with a preconcentration factor of 200 for Hg（Ⅱ） off-line analysis was conducted by cold vapor atomic absorption analysis.
