Liu Yue, Li Yan, Wu Zhi-Qiang, Yan Xiu-Ping
Key Laboratory of Functional Polymer Materials (Nankai University), Ministry of Education, Research Center for Analytical Sciences, College of Chemistry, Nankai University, Tianjin, China.
Talanta. 2009 Oct 15;79(5):1464-71. doi: 10.1016/j.talanta.2009.06.007. Epub 2009 Jun 12.
Hexahistidine-tagged protein functionalized multi-walled carbon nanotubes (MWCNTs/6His-tagged protein) were prepared and characterized by ultraviolet-visible spectrophotometry and atomic force microscopy. Both static and dynamical adsorption experiments showed that the MWCNTs/6His-tagged protein served as good sorbent for the solid-phase extraction of Cu(2+) and Ni(2+). Effective on-line sorption of Cu(2+) and Ni(2+) on the MWCNTs/6His-tagged protein packed microcolumn was achieved in a pH range of 3.0-4.5 and 4.5-6.0, respectively. The retained Cu(2+) and Ni(2+) were efficiently eluted with 0.2mol L(-1) imidazole-HCl solution for on-line flame atomic absorption spectrometric determination. The MWCNTs/6His-tagged protein exhibited fairly fast kinetics for the sorption of Cu(2+) and Ni(2+), and offered up to 20,000 and 1800 times improvement in the tolerable concentrations of co-existing ions over the MWCNTs for solid-phase extraction of Cu(2+) and Ni(2+), respectively. On-line solid-phase extraction at a flow rate of 5.0 mL min(-1) for 60s gave an enhancement factor of 29 for Cu(2+) and 28 for Ni(2+), a sample throughput of 45 h(-1), and a detection limit (3s) of 0.31 microg L(-1) for Cu(2+) and 0.63 microg L(-1) for Ni(2+). The precision for 11 replicate measurements was 2.4% for 10 microg L(-1) Cu(2+), and 2.5% for 15 microg L(-1) Ni(2+).
制备了六组氨酸标签蛋白功能化的多壁碳纳米管（MWCNTs/6His标签蛋白），并通过紫外可见分光光度法和原子力显微镜对其进行了表征。静态和动态吸附实验均表明，MWCNTs/6His标签蛋白是用于固相萃取Cu(2+)和Ni(2+)的良好吸附剂。在pH值分别为3.0 - 4.5和4.5 - 6.0的范围内，Cu(2+)和Ni(2+)能有效地在线吸附到填充有MWCNTs/6His标签蛋白的微柱上。保留的Cu(2+)和Ni(2+)用0.2mol L(-1)咪唑 - HCl溶液高效洗脱，用于在线火焰原子吸收光谱测定。MWCNTs/6His标签蛋白对Cu(2+)和Ni(2+)的吸附表现出相当快的动力学，与用于固相萃取Cu(2+)和Ni(2+)的MWCNTs相比，共存离子的耐受浓度分别提高了多达20000倍和1800倍。以5.0 mL min(-1)的流速进行60 s的在线固相萃取，Cu(2+)的增强因子为29，Ni(2+)的增强因子为28，样品通量为45 h(-1)，Cu(2+)的检测限（3s）为0.31 μg L(-1)，Ni(2+)的检测限为0.63 μg L(-1)。对于10 μg L(-1)的Cu(2+)，11次重复测量的精密度为2.4%，对于15 μg L(-1)的Ni(2+)，精密度为2.5%。
