Preparation of Hybrid Silica particles/Hyper-branchedPoly(amidoamine) Silica particles for Metal Ions Sensor

Abstract

A solid state chemosensor of hyper-branched polyamidoamine hybrid silica particles immobilized with TMPyP(α,β,γ,δ– tetrakis(1-methylpyridinium-4-yl)porphine p– toluenesulfonate) probe molecules was prepared for the detection of Cd(II) ions by optochemical method. Multifunctional hybrid silica(MHS) particles using vinyltrimethoxysilane(VTMS), 3-mercaptopropyltrimethoxysilane(MPTMS) and (3-aminopropyl) trimethoxysilane(APTMS) were synthesized by a two-step sol-gel process, and hyper-branched poly(amidoamine) silica particles were synthesized by the Michael addition with methyl acrylate(MA) and the amidation reaction with ethylenediamine(EDA) on the surface of MHS particles. The degree of hyper branched reaction for each generation particles was investigated by IR spectrum. Surface modification for immobilization of TMPyP probe molecules was carried through H2O2 oxidation reaction for MHS particles and thiol termination/H2O2 oxidation reaction for hyper-branched particles. Sensor particles were prepared with MHS-SO3H, G3.0-SO3H and G5.0-SO3H particles immobilized with TMPyP sensor probe molecules using ion-pair interaction. Exposure of TMPyP immobilized particles to Cd(II) ions results on the formation of TMPyP-Cd(II) complex and both colorimetric and UV-vis spectroscopy methods were used to investigate the detection of Cd(II) ions upon addition of Cd(II) ions, while the color of sensor particles was changed from red-brown to green. The absorption spectrum of TMPyP immobilized particles shows an intense Soret band at 430nm, which is shifted to 460nm with the formation of TMPyP-Cd(II) complex.