Removal of sudan dyes from water with C18-functional ultrafine magnetic silica nanoparticles

In this study, the new C18-functionalized ultrafine magnetic silica nanoparticles (C18-UMS NPs) were successfully synthesized and applied for extraction of sudan dyes in water samples based on the magnetic solid-phase extraction (MSPE). The extraction and concentration were carried out in one step by blending C18-UMS NPs and water samples. The sudan dyes adsorbed C18-UMS NPs were isolated from the matrix easily with an external magnetic field. After desorption the quantitation of sudan dyes was done by ultra fast liquid chromatography (UFLC). Satisfactory extraction recovery can be obtained with only 50 mg C18-UMS NPs. The effects of experimental parameters, including the amount of the nanoparticles, extraction time, pH value, desorption solvent, volume of desorption solvent and desorption time were investigated. The limits of detection for sudan I, II, III and IV were 0.066, 0.070, 0.12 and 0.12 ng mL−1, respectively. Recoveries obtained by analyzing the six spiked water samples were between 68% and 103%.