Almeda S, Gandolfi H E, Arce L, Valcárcel M
Department of Analytical Chemistry, University of Córdoba, Campus de Rabanales, E-14071 Córdoba, Spain.
J Chromatogr A. 2009 Aug 21;1216(34):6256-8. doi: 10.1016/j.chroma.2009.06.070. Epub 2009 Jul 1.
Although capillary electrophoresis (CE) with photometric detection is a well-established technique for the determination of various inorganic ions, its limited sensitivity has hindered greater development in this area. In this work, we used a mixture of metals consisting of Co(II), Ni(II), Zn(II) and Mn(II) to demonstrate that the sensitivity of CE with ultraviolet-visible (UV-vis) detection can be improved by using chromogenic reagents such as porphyrins. To this end, the metals were reacted with 5,10,15,20-tetrakis(4-sulphophenyl)-porphine dodecahydrate (TPPS(4)) to obtain their respective porphyrinato complexes, which were then separated by CE with a citrate buffer and detected at 410 nm. The ensuing electrophoretic method has a limit of detection (LOD) of 3 x 10(-6) M (180 microg L(-1)) for Co(II), 2 x 10(-10) M (0.012 microg L(-1)) for Ni(II), 4 x 10(-6) M (260 microg L(-1)) for Zn(II) and 4 x 10(-9) M (0.219 microg L(-1)) for Mn(II). The method is a highly promising choice for the ultratrace determination of Ni(II) and Mn(II).
尽管采用光度检测的毛细管电泳(CE)是一种成熟的测定各种无机离子的技术,但其有限的灵敏度阻碍了该领域的进一步发展。在这项工作中,我们使用了由钴(II)、镍(II)、锌(II)和锰(II)组成的金属混合物,以证明通过使用诸如卟啉等显色剂可以提高紫外可见(UV-vis)检测的毛细管电泳的灵敏度。为此,将这些金属与5,10,15,20-四(4-磺酸苯基)-卟啉十二水合物(TPPS(4))反应,以获得它们各自的卟啉配合物,然后用柠檬酸盐缓冲液通过毛细管电泳进行分离,并在410nm处进行检测。随后的电泳方法对钴(II)的检测限(LOD)为3×10⁻⁶M(180μg L⁻¹),对镍(II)为2×10⁻¹⁰M(0.012μg L⁻¹),对锌(II)为4×10⁻⁶M(260μg L⁻¹),对锰(II)为4×10⁻⁹M(0.219μg L⁻¹)。该方法是超痕量测定镍(II)和锰(II)的极有前景的选择。