Aminopropyl-Silica Gel Modified with Nickel(II)-Phthalocyanine for Separation of π-Electron Rich Compounds by High Performance Liquid Chromatography

Aminopropyl-silica gels modified with a nickel(II)-phthalocyanine derivative (Ni-PCSD) were evaluated as HPLC-stationary phases for the separation of π-electron rich compounds such as polyaromatic hydrocarbons (PAHs) and mutagens. A column packed with Ni-PCSD retains some π-electron rich compounds longer than a column packed with copper(II)-phthalocyanine derivatives (Cu-PCSD), suggesting that a π-π electron interaction and an additional interaction between Ni-PCS and the compound. On the basis of the retention data of fourring PAHs, anthracene derivatives and heterocyclic aromatic hydrocarbons, we propose that the additional interaction would be due to an interference of the π- or n-electrons would interact and with the d-orbital of the Ni atom in Ni-PCS. Further, the Ni-PCSD column is expected to be superior to the Cu-PCSD column for the separations of drugs, mutagens and pollutants which have both π-electrons and ligand atom(s).