HPLC Retention Behaviors of π-Electron Rich Compounds on Ni2+- and Cu2+-Phthalocyanine Derivatives Bound to Silica Gels in Polar Eluents

The effect of the central metal of columns packed with silica gels binding Ni2+- and Cu2+-phthalocyanine derivatives (Ni-and Cu-PCSDs) on the retention behavior of poly-aromatic-hydrocarbons (PAHs) thereof in a polar eluent was examined. The retention factors of PAHs on the Ni- and Cu-PCSDs in 80% methanol showed a good linear correlation. The Cu-PCSD column exhibited the π-π interactions for PAHs, while the Ni-PCSD column exhibited the π-d interactions for PAHs in addition to the π-π interaction for PAHs. Further, an investigation of the retention behavior of anthracene derivatives having different substituents revealed that the Ni- and Cu-PCSD columns could recognize the differences of substituents only in a polar eluent.