New sol-gel silica nanoparticles coated cyanopropyltriethoxysilane as alternative solid phase extraction sorbent for organophosphorus pesticides

Abstract

Sorbents based on silica are widely used in solid phase extraction (SPE). The most common SPE material is C18.Recently nanoparticleshave gained interest as sorbent materials for analytical purpose. In this study silica-based nanoparticles with polar and non-polar groups were synthesized using cyanopropyltriethoxysilane (CNPrTEOS) and tetraethoxysilane (TEOS) as precursor in the presence of ammonia solution as catalyst and ethanol as solvent via sol-gel technology. The sol-gel SiO2-NPs-CNPrTEOS was used for the simultaneous extraction of three organophosphorus pesticides (OPPs) of different polarity namely dicrotophos, diazinon and chlorpyrifos prior to LC-UV detection at 270 nm. The sorbent produced was characterized using FTIR, FESEM, nitrogen gas adsorption and TGA. The surface area and average pore diameter of the sorbent are 570 m2 g-1 and 31Å (mesoporous), respectively. The average particle size of SiO2-NPs-CNPrTEOS is 54 nm. The mesoporous SiO2-NPs-CNPrTEOS showed superior extraction capability for the polar dicrotophos and also for the non-polar diazinon and chlorpyrifos compared to commercial cyano SPE. The new SiO2-NPs-CNPrTEOS exhibits high potential as a bipolar sorbent for the simultaneous extraction of polar and non-polar OPPs. Keywords Sol-gel, Solid phase extraction, Nanoparticles sorbent, Cyanopropyltriethoxysilane, Tetraethoxysilane, Organophosphorus pesticides, Liquid chromatography-UV detection.