Determination palladiums have been reported 5% (w/w) Pd/BaSO4 known as Rosenmund Catalyst. The determination of palladium II known as Rosenmund Catalyst is always an expensive procedure usually involving procedures su...Determination palladiums have been reported 5% (w/w) Pd/BaSO4 known as Rosenmund Catalyst. The determination of palladium II known as Rosenmund Catalyst is always an expensive procedure usually involving procedures such as flame atomic absorption spectrophotometry, emission spectrometry, and many spectrophotometric methods. In this study, palladium II in 5% Pd/BaSO4, was synthesized and employed to develop an extractive UV-Visible Spectrophotometric, and an inductively coupled plasma mass spectrometry ICP/MS methods for the determination of palladium II. Specification for Pd is 4.85% to 5.10%;the result was 4.97% for the UV-Visible spectrophotometer and 4.90% for the ICP/MS. Both results meet the requirements.展开更多
Baking meat by wrapping them in Aluminum (Al) foil is common in many countries. The excessive use of Al foil in baking and the disagreement about using Al foils were the motivation to do this study especially after th...Baking meat by wrapping them in Aluminum (Al) foil is common in many countries. The excessive use of Al foil in baking and the disagreement about using Al foils were the motivation to do this study especially after the 2007 WHO/FDA Report. In this investigation, a gravimetric and a UV-Vis spectrophotometric method are used to estimate Aluminum (Al) leaching into meat baked by wrapping in Al foil. Three kinds of meat were used fish, cow stakes and chicken. The importance of Al exposure area was neglected by many studies. Five factors affecting Al leaching into meat are studied (baking temperature, baking time, additives, Al exposure area and weight of meat). The effect of cooking times (20, 40, 60 minutes) at 180℃ and cooking temperatures (160℃, 180℃, 200℃) at 60 minutes on the amount of Al leaching were evaluated. It was found that Al leaching into meat increased with increasing temperature, baking time, additives and Al exposure area. Moreover, Al exposure area was more effective than the weight of the meat. The Al leaching was highest in fish and lowest in chicken. Comparing the present results with the Provisional Tolerance Weekly Intake of Al approved by WHO/FDA, it shows that Al leaching into meat baked by wrapping in Al foil may add considerable doses into the diet. Continuous monitoring of Al foil used for baking meat is recommended.展开更多
An apparatus was set up for in situ UV- Vis determintion of ethylene polymerization under atmospheric pressure. In three different solvents, tetrahydrofuran(THF), chlorobenzene and dimethyl formamide (DMF), and using ...An apparatus was set up for in situ UV- Vis determintion of ethylene polymerization under atmospheric pressure. In three different solvents, tetrahydrofuran(THF), chlorobenzene and dimethyl formamide (DMF), and using MAO as cocatalyst,α- diimine/nickel catalytic system was prepared for ethylene polymerization with the UV- Vis testing system. In THF, active peak at 545 nm and inactive peak at 660 nm were observed. In chlorobenzene, active peak at 520 nm, 570 nm, and inactive peak at 660 nm were also observed. The regularities of growth and disappearence of active peaks were investigated. The structure of active species and solvent effect were discussed.展开更多
文章选取了20个以J酸及其衍生物为偶合组分的双偶氮红色活性染料,采用密度泛函理论(DFT),选用B3LYP和PBE0两种杂化泛函在6-31+G(d)基组水平上计算了染料的紫外吸收光谱。通过计算光谱与实验光谱比较发现,B3LYP计算的激发能与实验值更吻...文章选取了20个以J酸及其衍生物为偶合组分的双偶氮红色活性染料,采用密度泛函理论(DFT),选用B3LYP和PBE0两种杂化泛函在6-31+G(d)基组水平上计算了染料的紫外吸收光谱。通过计算光谱与实验光谱比较发现,B3LYP计算的激发能与实验值更吻合,其绝对平均误差(MAE)为0.127 e V,PBE0给出了一个略大误差,其绝对平均误差为(MAE)为0.180 e V。染料分子的主要吸收谱峰主要源于电子从HOMO,HOMO-1,HOMO-2到LUMO,LUMO+1间的π—π*跃迁。展开更多
文摘Determination palladiums have been reported 5% (w/w) Pd/BaSO4 known as Rosenmund Catalyst. The determination of palladium II known as Rosenmund Catalyst is always an expensive procedure usually involving procedures such as flame atomic absorption spectrophotometry, emission spectrometry, and many spectrophotometric methods. In this study, palladium II in 5% Pd/BaSO4, was synthesized and employed to develop an extractive UV-Visible Spectrophotometric, and an inductively coupled plasma mass spectrometry ICP/MS methods for the determination of palladium II. Specification for Pd is 4.85% to 5.10%;the result was 4.97% for the UV-Visible spectrophotometer and 4.90% for the ICP/MS. Both results meet the requirements.
文摘Baking meat by wrapping them in Aluminum (Al) foil is common in many countries. The excessive use of Al foil in baking and the disagreement about using Al foils were the motivation to do this study especially after the 2007 WHO/FDA Report. In this investigation, a gravimetric and a UV-Vis spectrophotometric method are used to estimate Aluminum (Al) leaching into meat baked by wrapping in Al foil. Three kinds of meat were used fish, cow stakes and chicken. The importance of Al exposure area was neglected by many studies. Five factors affecting Al leaching into meat are studied (baking temperature, baking time, additives, Al exposure area and weight of meat). The effect of cooking times (20, 40, 60 minutes) at 180℃ and cooking temperatures (160℃, 180℃, 200℃) at 60 minutes on the amount of Al leaching were evaluated. It was found that Al leaching into meat increased with increasing temperature, baking time, additives and Al exposure area. Moreover, Al exposure area was more effective than the weight of the meat. The Al leaching was highest in fish and lowest in chicken. Comparing the present results with the Provisional Tolerance Weekly Intake of Al approved by WHO/FDA, it shows that Al leaching into meat baked by wrapping in Al foil may add considerable doses into the diet. Continuous monitoring of Al foil used for baking meat is recommended.
基金the National Natural Science Foundation of China(5117214451372153)+2 种基金Science Technology Foundation of shanghai(12410710300)Leading Academic Discipline Project of Shanghai Municipal Education Commission(J51503)the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning
文摘An apparatus was set up for in situ UV- Vis determintion of ethylene polymerization under atmospheric pressure. In three different solvents, tetrahydrofuran(THF), chlorobenzene and dimethyl formamide (DMF), and using MAO as cocatalyst,α- diimine/nickel catalytic system was prepared for ethylene polymerization with the UV- Vis testing system. In THF, active peak at 545 nm and inactive peak at 660 nm were observed. In chlorobenzene, active peak at 520 nm, 570 nm, and inactive peak at 660 nm were also observed. The regularities of growth and disappearence of active peaks were investigated. The structure of active species and solvent effect were discussed.
文摘文章选取了20个以J酸及其衍生物为偶合组分的双偶氮红色活性染料,采用密度泛函理论(DFT),选用B3LYP和PBE0两种杂化泛函在6-31+G(d)基组水平上计算了染料的紫外吸收光谱。通过计算光谱与实验光谱比较发现,B3LYP计算的激发能与实验值更吻合,其绝对平均误差(MAE)为0.127 e V,PBE0给出了一个略大误差,其绝对平均误差为(MAE)为0.180 e V。染料分子的主要吸收谱峰主要源于电子从HOMO,HOMO-1,HOMO-2到LUMO,LUMO+1间的π—π*跃迁。
