Potential of porphyrins as chromogenic reagents for determining metals in capillary electrophoresis.
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).
Almeda
S
S
Department of Analytical Chemistry, University of Córdoba, Campus de Rabanales, E-14071 Córdoba, Spain.
Gandolfi
H E
HE
Arce
L
L
Valcárcel
M
M
D019075:Electrophoresis, Capillary / Q000379:methods*; D007202:Indicators and Reagents; D007477:Ions / Q000032:analysis* / Q000302:isolation & purification; D008345:Manganese / Q000032:analysis / Q000302:isolation & purification; D008670:Metals / Q000032:analysis* / Q000302:isolation & purification; D009532:Nickel / Q000032:analysis / Q000302:isolation & purification; D011166:Porphyrins / Q000737:chemistry*
D007202:Indicators and Reagents; D007477:Ions; D008670:Metals; D011166:Porphyrins; C016136:tetraphenylporphine sulfonate; D008345:Manganese; D009532:Nickel