Analytical Sciences

Abstract − Analytical Sciences, 17(2), 301 (2001).

Effects of Trimethylsilylation of Copper(II)-Phthalocyanine Sulfonyl-Aminopropyl Silica Gels on the Separation of pi-Electron-Rich Compounds by High-Performance Liquid Chromatography
Akimasa IWADO,*1 Masaki MIFUNE,* Yoshihiro MORI,*1 Midori ONODA,*1 Takemine KANAI,*1 Noriko MOTOHASHI,*3 Jun HAGINAKA,*4 and Yutaka SAITO*2
*1 The Graduate School of Natural Science and Technology, Okayama University, Tsushima-Naka, Okayama 700-0072, Japan
*2 Faculty of Pharmaceutical Sciences, Okayama University, Tsushima-Naka, Okayama 700-8530, Japan
*3 Kobe Pharmaceutical University, Motoyamakita-Machi, Higashinada, Kobe 658-0003, Japan
*4 Faculty of Pharmaceutical Sciences, Mukogawa Women's University, Koshien, Nishinomiya 663-8179, Japan
As an attempt to elucidate the factor(s) responsible for the poor performance of a copper(II)-phthalocyanine aminopropyl-silica gels (Cu-PCSD) column for HPLC, the silanol and/or amino groups remaining on Cu-PCSD were endcapped with trimethylchlorosilane (TMCS) or N-trimethylsilylimidazole (TMSI). The trimethylsilylated Cu-PCSDs (Cu-PCSD-TMCS and -TMSI) were investigated concerning their performance as an HPLC-stationary phase in the separation of pi-electron-rich polyaromatic hydrocarbons (PAHs), such as mutagenic anthracene and pyrene. As a result, trimethylsilylation with TMSI, which reacts only with silanol-groups, was not effective to improve the column efficiency. In contrast, trimethylsilylation by TMCS, which reacts with both the silanol- and amino-groups, improved the theoretical plate numbers (N) for PAHs separation with the Cu-PCSD column, indicating that the low N values on the Cu-PCSD column were caused by electrostatic interactions between PAHs and the remaining amino-groups on Cu-PCSD. Furthermore, the retention data of mutagenic heterocyclic amines (HCAs) indicated that the remaining amino groups interact with the polar groups of HCAs.