title: Enhancement of retentivity and selectivity for PAHs in NP-HPLC by high-density immobilization of poly(4-vinylpyridine) as an organic phase on silica.
abstract: Poly(4-vinylpyridine)-modified silica with high grafting density have been prepared by a grafting-from (g-from) approach through radical chain-transfer reactions. The widely used silane coupling agent 3-mercaptopropyltrimethoxysilane was used to prepare thiol-terminated silica. Chain-transfer reaction and polymerization of 4-vinylpyridine was carried out using alpha,alpha'-azobisisobutyronitrile as an initiator. Thiol-terminated silica and polymer-modified silica were both characterized qualitatively and quantitatively. The quantification of the organic phase has been done by thermogravimetric analysis and elemental analysis. Thus, the modified silica was used as a packing material and the retention behavior of polycyclic aromatic hydrocarbons (PAHs) was studied in normal-phase high-performance liquid chromatography. Results were compared with those of poly(4-vinylpyridine)-modified silica prepared by a grafting-to (g-to) approach. Commercially available aminopropyl-bonded silica and bare silica columns were also used as reference columns. The column of poly(4-vinylpyridine)-grafted silica prepared by the g-from method, having higher grafting density, provided the better retentivity and selectivity for PAHs compared to the other reference columns.
authors.affiliation: Department of Applied Chemistry and Biochemistry, Kumamoto University.
authors.forename: Usha
authors.initials: U
authors.lastname: Ghimire Gautam
authors.forename: Mani P
authors.initials: MP
authors.lastname: Gautam
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Sawada
authors.forename: Makoto
authors.initials: M
authors.lastname: Takafuji
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Ihara