Dispersive Magnetic Solid Phase Extraction Sorbent of Octadecyl/Silica/Magnetie Nanoparticles for the Determination of Tetracyclines in Water Samples

Abstract

This thesis aimed to develop a new magnetic solid phase extraction sorbent of magnetite nanoparticles coated with silica and octadecyl (C18/SiO2/Fe3O4) for the extraction and preconcentration of tetracyclines in water samples. The magnetite nanoparticles facilitated a convenient magnetic separation of sorbent from an aqueous sample using an external magnet, the silica layer helped to prevent the aggregation of the magnetite nanoparticles and the octadecyl layer helped to enhance the adsorption ability. To obtain the highest extraction efficiency with the shortest analysis time, the effect of various parameters were optimized including the amount of sorbent, sample pH, stirring rate, extraction time and desorption conditions. Under the optimum conditions, the calibration curves were linear over the concentration range of 0.0020 to 1.0 μg mL for oxytetracycline and 0.010 to 1.0 μg mL for tetracycline and chlortetracycline. The limit of detections were 0.002 μg mL1 for oxytetracycline and 0.01 μg mL1 for tetracycline and chlortetracycline. The satisfactory recoveries were obtained in the range of 82 to 88% with the relative standard deviations were less than 10%. The developed method was successfully applied for the extraction and determination of tetracyclines from water samples with a several advantages such as simplicity, rapid and convenience, cost-effectiveness and high extraction efficiency.