Grafting of Silica Particles with Linoleic Acid via Modified Stober’s Method for Preconcenrtration of Pesticides in Drinking Water

Abstract

The extensive use of pesticides in agricultur has raised toxicity level in environment because of their mutagenic and carcinogenic activity. A sensitive technique is needed to develop for the detection of pesticides to get high sensitivity and selectivity in complex matrices. Modified Stober‘s method was used for the synthesis of pure SiO2 particles and grafted by linoleic acid. Grafted SiO2 were examined for its capability as a sorbent for removal and preconcentration of four organochlorine pesticides i.e. endrin, dieldrin, aldrin and DDT. The particles of SiO2 undergo hydrophobic interaction with linoleic acid by grafting. Both pure SiO2 and linoleic acid grafted SiO2 particles were characterized by SEM, FTIR and XRD. FTIR confirmed the grafting of SiO2 with linoleic acid. XRD and SEM results showed monodispersed and spherical SiO2 particles. The evaluation of grafted SiO2 was carried out by spiking organochlorine pesticides in drinking water. The grafted SiO2 particles could be used as a sorbent in solid phase extraction followed by high performance liquid chromatography with reverse phase C18 column with aqueous acetonitrile as a mobile phase with ultraviolet detector at 224 nm. The percent recoveries for aldrin, dieldin, endrin and DDT were 81, 52, 60 and 91%, respectively.