OHMURO Satoshi, Ph.D. / Assistant Professor
Division of Physical and Analytical Chemistry
Department of Pharmaceutical Sciences
1. Analysis of mass transfer between aqueous phase and ODS phase in solid phase extraction.
2. Effect of residual silanol in ODS silica for retention of reagents in solid phase extraction.
3. Development of a new solid phase extraction system utilizing residual silanol in ODS silica.
Octadecylsilyl (ODS) silica is most popular material for reversed phased high performance liquid chromatography (RP-HPLC) in separation analytical chemistry. Residual silanol in ODS silica generally is capped by trimethylsilyl groups. This is also used in solid phase extraction (SPE). There were, however, few reports that end–capped ODS silica is suitable for SPE. We have studied that function of residual silanol in ODS silica and retention mechanism of reagents from solution phase to ODS phase in SPE. As a result, nonpolar reagents were retained by distribution, while polar reagents were retained by both distribution and adsorption. In particular, it was clarified that adsorption to residual silanol greatly contributes to the retention of the ligand from organic phase.
1. Kenji Yamamoto, Shin’ya Mitsuda, Naomi Ohtake, Natsuki Murashige, Satoshi Ohmuro, Akio Yuchi, “Perchlorate selectivity of anion exchange resins as evaluated using ion-selective electrodes” , Anal. Sci. 33, 159 (2017).
2. Satoshi Ohmuro, Kan Fujii, Takashi Yasui, Kazutake Takada, Akio Yuchi, Hisao Kokusen, “Enhanced retention of chelating reagent in octadecylsilyl silica phase by interaction with residual silanol group in solid phase extraction of divalent metal ions”, Anal. Sci. 32, 343 (2016).
3. Satoshi Ohmuro, Hiromasa Kishi, Nobutoshi Yoshihara, Hisao Kokusen, “Liquid-liquid extraction of divalent transition metal ion with a novel bis-β-ketoester extraction reagent” , Talanta 128, 102 (2014).