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。
