Synthesis and Solid-State NMR Investigations of Radiation-Immobilized Polysiloxanes on Bare, Titanium-Grafted, and Zirconium-Grafted Silicas

Abstract

Three different reversed-phase materials for high-performance liquid chromatography, obtained by sorption of poly(methyloctylsiloxane) (PMOS) onto bare silica, titanized silica, and zirconized silica pores, followed by immobilization with γ-radiation, were characterized by means of solid-state NMR spectroscopy. The surface properties of these stationary phases were investigated by 29Si CP/MAS and 13C CP/MAS NMR spectroscopy. γ-Radiation causes the formation of new bonds, either between PMOS and the different supports or between different siloxane chains, which leads, in either case, to a higher amount of polysiloxane immobilized onto the silica support material.

Al2O3-coated 3-N-propylpyridinium chloride silsesquioxane polymer film: preparation and electrochemical property study of adsorbed cobalt tetrasulfophthalocyanine

“…The use of surface-modified porous solids as substrates for modification with thin layers of films having organofunctional groups such as ion exchangers, basic donor atoms, long-chain hydrocarbons, and metal oxides, prepared by grafting or sol-gel processing methods, has found numerous applications in adsorption [1], separation processes [2][3][4] and immobilization of electroactive species [5] and as catalysts [6] and sensors [7][8][9][10][11].…”

An overview of the chromatographic properties and stability of C18 titanized phases

“…Solid-state 29 Si NMR also brings significant information about the different silicon species on the titanized surface [33]. In the spectrum of Fig.…”

“…3, the signals at -101 and -110 ppm are attributed to the silanol (Q monofunctional silanes, respectively, are also detected in this spectrum. The structural types from the trifunctional silylant agent are denoted as T n where n is related to the number of the siloxane bonds [33].…”

High-performance liquid chromatographic determination of pesticides in tomatoes using laboratory-made NH2 and C18 solid-phase extraction materials

“…However, this method has some limitations, such as: high reagent cost, time consuming synthesis procedure, use of toxic solvents and reagents and the need for an inert atmosphere and high temperatures to carry out the process. An interesting alternative, successfully used to prepare several HPLC stationary phases, such as, poly(methyloctylsiloxane) (PMOS) immobilized onto zirconized silica [6,7], titanium-grafted silica [8,9] and pure silica [10][11][12], is the substitution of the chemical reaction by depositing a polymer on the support and then immobilizing the polymer using a thermal treatment or gamma irradiation. SPE sorbents based on poly(methyloctadecylsiloxane) (PMODS) immobilized onto silica by gamma radiation or thermal treatment have been described [13][14][15] and applied for the pre-concentration of pesticides in grapes, water and urine samples, respectively.…”