A simple and selective method using a column packed with graphene oxide（GO） as a solid phase extractant has been developed for the multi-element preconcentration of Fe（Ⅲ）,Ni（Ⅱ）,Cu（Ⅱ） and Zn（Ⅱ）ions prior ...A simple and selective method using a column packed with graphene oxide（GO） as a solid phase extractant has been developed for the multi-element preconcentration of Fe（Ⅲ）,Ni（Ⅱ）,Cu（Ⅱ） and Zn（Ⅱ）ions prior to flame atomic absorption spectrometric determinations.The method is based on the sorption of mentioned ions on synthesized GO using 2-（tert-butoxy）-N-（3-carbamothioylphenyl）acetamide as a chelating agent.Several parameters on the extraction and complex formation were optimized.Under the optimized conditions（pH 6,flow rate 9 mL/min）,metal ions were retained on the column,then quantitatively eluted by HNO3solution（5 mL,3.0 mol/L）.The preconcentration factor was calculated as250.The detection limits for the analyte ions of interest were found in the range of 0.11 ng/mL（Ni2＋） to0.63 ng/mL（Cu2＋）.The column packed with GO was adequate for metal ions separation in matrixes containing alkali,alkaline earth,transition and heavy metal ions.展开更多
We reported a quantum mechanical study of the complexes formed between Sm3＋ and the bisphosphonate ligand pamidronate in aqueous solution. According to available experimental p K a values pamidronate was expected to ...We reported a quantum mechanical study of the complexes formed between Sm3＋ and the bisphosphonate ligand pamidronate in aqueous solution. According to available experimental p K a values pamidronate was expected to exist in aqueous solution, at physiologically relevant p H, in its di- and tri-protonated forms（denoted by H3 L and H2L）. The most stable structures of the ligands and Sm3＋ complexes were found by using a detailed analysis of the conformational space with semiempirical and DFT methods. The results showed that both H2 L and H3 L bisphosphonates acted as a tridentate ligands in their complexes with Sm3＋. The addition of explicit water molecules to the coordination sphere of the metal not only gave different coordination numbers for H2 L and H3 L complexes（CN=9 and 10）, but also provided different trends in stabilization energies. The results highlighted the importance of considering not only an explicit first coordination shell, but also a second hydration shell, for an adequate description of this type of complexes in aqueous solution.展开更多
文摘A simple and selective method using a column packed with graphene oxide（GO） as a solid phase extractant has been developed for the multi-element preconcentration of Fe（Ⅲ）,Ni（Ⅱ）,Cu（Ⅱ） and Zn（Ⅱ）ions prior to flame atomic absorption spectrometric determinations.The method is based on the sorption of mentioned ions on synthesized GO using 2-（tert-butoxy）-N-（3-carbamothioylphenyl）acetamide as a chelating agent.Several parameters on the extraction and complex formation were optimized.Under the optimized conditions（pH 6,flow rate 9 mL/min）,metal ions were retained on the column,then quantitatively eluted by HNO3solution（5 mL,3.0 mol/L）.The preconcentration factor was calculated as250.The detection limits for the analyte ions of interest were found in the range of 0.11 ng/mL（Ni2＋） to0.63 ng/mL（Cu2＋）.The column packed with GO was adequate for metal ions separation in matrixes containing alkali,alkaline earth,transition and heavy metal ions.
文摘We reported a quantum mechanical study of the complexes formed between Sm3＋ and the bisphosphonate ligand pamidronate in aqueous solution. According to available experimental p K a values pamidronate was expected to exist in aqueous solution, at physiologically relevant p H, in its di- and tri-protonated forms（denoted by H3 L and H2L）. The most stable structures of the ligands and Sm3＋ complexes were found by using a detailed analysis of the conformational space with semiempirical and DFT methods. The results showed that both H2 L and H3 L bisphosphonates acted as a tridentate ligands in their complexes with Sm3＋. The addition of explicit water molecules to the coordination sphere of the metal not only gave different coordination numbers for H2 L and H3 L complexes（CN=9 and 10）, but also provided different trends in stabilization energies. The results highlighted the importance of considering not only an explicit first coordination shell, but also a second hydration shell, for an adequate description of this type of complexes in aqueous solution.
