The utilization of porphyrins in quantitative determination of some transition metals by thin layer chromatography

In this work, high performance thin layer chromatography has been used to quantify metal ions in various analytical medium. The 5, 10, 15, 20-tetrakis(bromohydroxyphenyl) porphyrin as chelating agent and the Zn(II), Ni(II), Cu(II), Co(II), Cd(II), Hg(II), Pb(II), Mn(II), Pt(IV) and Pd(II)-TBHPP chelates were synthesized and their structural and chromatographic behaviours were determined using IR, NMR, absorption and fluorescence spectrometry and thin layer chromatography. In quantification, using solid phase extraction C18 cartridge metal ions were enriched and retain metal chelates were eluted with tetrahydrofuran. The chelates were separated on HPTLC silica gel plate using aceton:chloroform (2:8, v:v) as mobile phase. Only, the TBHPP complexes with Zn(II), Cu(II), Co(II) and Hg(II) migrate differently from each other. Linear working range of TBHPP complexes with Zn(II), Cu(II), Co(II) and Hg(II) were 3.6-30, 1.2-30, 0.6-30, 3.6-60 ng µL-1, respectively. LOD of TBHPP complexes with Zn(II), Cu(II), Co(II) and Hg(II) were 0.92 ng µL-1, 1.21 ng µL-1, 0.19 ng µL-1, 0.90 ng µL-1, respectively. Repeatibility for within- and between-day (RSD%) of TBHPP complexes with Zn(II), Cu(II), Co(II) and Hg(II) were 3.67 ? 5.24, 2.66 ? 3.51, 1.87 ? 4.10, 3.09 ? 4.51, respectively. The method was applied to the determination of Zn(II), Cu(II), Co(II) and Hg(II) in tap water, geothermal water, river water and dried tomato samples with good results.