制备了聚乙烯亚胺（PEI）功能化的石墨烯（G）修饰电极以实现抗坏血酸（AA）、多巴胺（DA）、尿酸（UA）和色氨酸（Trp）的分离及同时测定.采用红外光谱（FTIR）、紫外-可见吸收光谱（UV-Vis）、X射线粉末衍射仪（XRD）和透射电子显微镜...制备了聚乙烯亚胺（PEI）功能化的石墨烯（G）修饰电极以实现抗坏血酸（AA）、多巴胺（DA）、尿酸（UA）和色氨酸（Trp）的分离及同时测定.采用红外光谱（FTIR）、紫外-可见吸收光谱（UV-Vis）、X射线粉末衍射仪（XRD）和透射电子显微镜（TEM）对电极修饰材料进行了表征,并优化了该修饰电极同时测定AA,DA,UA和Trp的实验条件.在聚乙烯亚胺功能化石墨烯修饰的玻碳电极（PEI-G/GCE）上实现了AA,DA,UA和Trp氧化峰的分离,AA-DA,DA-UA和UA-Trp的氧化峰电位差分别为298,130和350 m V.该修饰电极对AA,DA,UA和Trp的检测线性范围分别为50~5800,30~2570,0.05~400和6~1000μmol/L;检出限分别为16.67,10,0.017和2μmol/L.展开更多
Linear low density polyethylene from ethylene as an o nly monomer was prepared by the combination catalyst system of Et(Ind) 2ZrCl 2 an d {2 [2 Me 4 Br C 6H 3NC(Me)] 2C 5H 3N}FeCl 2 activated with methy laluminoxane (...Linear low density polyethylene from ethylene as an o nly monomer was prepared by the combination catalyst system of Et(Ind) 2ZrCl 2 an d {2 [2 Me 4 Br C 6H 3NC(Me)] 2C 5H 3N}FeCl 2 activated with methy laluminoxane (MAO).The two catalysts were well matched in a single reactor and i t was observed that the “comonomer effect" appeared in the in situ copolymeriz ation of ethylene.The comonomer effect was some strongly influenced by the molar ratio of Al to (Fe+Zr) and the polymerization temperatures.At 60℃ and n(Al )/n(Fe+Zr)=2000,the maximum activity of the catalytic system(8 5×10\+6g/mo l·h) was 4\^25 times higher than that of homopolymerization of ethylene(2\^0×1 0\+6g/mol·h),and the value of n(Fe)/n(Zr) was 0 5.At n(Al)/n(F e+Zr)=1000,the maximum activity diminished.When polymerization temperatures incr eased,the maximum activity of the in situ copolymerization decreased and the co rresponding ratio of Fe to Zr also decayed.The copolymers made from this catalyt ic system had the characteristics of low melting point(from 132 34℃ to 70 97 ℃),low density(from 0 9467?g/cm\+3 to 0\^9283?g/cm\+3) and narrow molecular weight distribution(from 2\^29 to 1\^86).However,it’s no obvious influence of th e comonomer effect on the physical properties of the copolymers.展开更多
文摘制备了聚乙烯亚胺（PEI）功能化的石墨烯（G）修饰电极以实现抗坏血酸（AA）、多巴胺（DA）、尿酸（UA）和色氨酸（Trp）的分离及同时测定.采用红外光谱（FTIR）、紫外-可见吸收光谱（UV-Vis）、X射线粉末衍射仪（XRD）和透射电子显微镜（TEM）对电极修饰材料进行了表征,并优化了该修饰电极同时测定AA,DA,UA和Trp的实验条件.在聚乙烯亚胺功能化石墨烯修饰的玻碳电极（PEI-G/GCE）上实现了AA,DA,UA和Trp氧化峰的分离,AA-DA,DA-UA和UA-Trp的氧化峰电位差分别为298,130和350 m V.该修饰电极对AA,DA,UA和Trp的检测线性范围分别为50~5800,30~2570,0.05~400和6~1000μmol/L;检出限分别为16.67,10,0.017和2μmol/L.
文摘Linear low density polyethylene from ethylene as an o nly monomer was prepared by the combination catalyst system of Et(Ind) 2ZrCl 2 an d {2 [2 Me 4 Br C 6H 3NC(Me)] 2C 5H 3N}FeCl 2 activated with methy laluminoxane (MAO).The two catalysts were well matched in a single reactor and i t was observed that the “comonomer effect" appeared in the in situ copolymeriz ation of ethylene.The comonomer effect was some strongly influenced by the molar ratio of Al to (Fe+Zr) and the polymerization temperatures.At 60℃ and n(Al )/n(Fe+Zr)=2000,the maximum activity of the catalytic system(8 5×10\+6g/mo l·h) was 4\^25 times higher than that of homopolymerization of ethylene(2\^0×1 0\+6g/mol·h),and the value of n(Fe)/n(Zr) was 0 5.At n(Al)/n(F e+Zr)=1000,the maximum activity diminished.When polymerization temperatures incr eased,the maximum activity of the in situ copolymerization decreased and the co rresponding ratio of Fe to Zr also decayed.The copolymers made from this catalyt ic system had the characteristics of low melting point(from 132 34℃ to 70 97 ℃),low density(from 0 9467?g/cm\+3 to 0\^9283?g/cm\+3) and narrow molecular weight distribution(from 2\^29 to 1\^86).However,it’s no obvious influence of th e comonomer effect on the physical properties of the copolymers.
