Performance of three chemically‐ modified silica materials for solid phase extraction of polar compounds from aqueous solutions

Abstract

Performance of three chemically modified silica materials for solid phase extraction of polar compounds from aqueous solutions Silica gel (320 m 2 g -1 , 10 nm) was chemically modified with 3-chloropropyltrimethoxysilane or 3-aminopropyltrimethoxysilane, followed by reaction with aniline, 3-phenylchloropropylamine, or benzylamine. The resulting silicas were characterized by elemental analysis and spectroscopic techniques, namely diffuse reflectance spectroscopy (DRS), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), and 29 Si variable amplitude cross-polarization magic-angle spin nuclear magnetic resonance (VACP-MAS-NMR). The resulting solids were shown to be stable in aqueous and non-aqueous media and were tested as sorbents for pre-concentration of derivatized phenolic compounds (acetyl derivatives of: phenol, o-cresol, m-cresol, p-cresol, 2-ethylphenol, 3-ethylphenol, and 4-ethylphenol) and some organochlorine pesticides (endrin, pentachlorobenzene, heptachloro epoxide, hexachlorobenzene, and lindane) in aqueous media. Extraction experiments were undertaken using a precleaned cartridge (10 cm610 mm ID) packed with modified silica gel and with commercial C-18 in order to evaluate the influence of the nature of the functional group onretention of the compounds under study. Results showed that silica modified with aniline gave the highest retention for the studied acetylated phenolic compounds. Silica modified with 3-phenylchloropropyl groups exhibited the highest retention for hexachlorobenzene and aldrin, while that modified with benzylamine showed the highest retention for eldrin, pentachlorobenzene, and heptachloro epoxide. Lindane was not retained by any of the tested materials.

Organosilicas with Covalently Bonded Groups under Thermochemical Treatment

“…Porous silicas having an immobilized organic layer (chemically modified silicas, CMS) are widely used as adsorbents, 1 chromatography phases, 2,3 and catalysts. 4,5 Useful properties of such hybrid materials are determined by the chemical nature of their interfacial layer and particularly by its composition, [6][7][8] geometry, 9 and topography (microheterogeneity). 10,11 Certainly, the composition of the im-mobilized layer is most crucial.…”

Synthesis of zirconocene-based silica phases and evaluation in lindane and heptachlor epoxide adsorption/desorption

“…In a previous study, we evaluated the SPE capability of three new modified silica phases, based on silica modification with aniline, 3-phenyl chloropropylamine, and benzylamine as sorbents for acetylated phenolic compounds and organochlorine pesticides in aqueous milieu [10]. In the present study, two new solid-phase families have been prepared: one resulting from Cp 2 ZrCl 2 and (nBuCp) 2 ZrCl 2 grafting onto silica and another consisting of a hybrid silica synthesized by the sol-gel method bearing indenyl and indenyl zirconocene on its phase.…”