Click chemistry-based synthesis of water-dispersible hydrophobic magnetic nanoparticles for use in solid phase extraction of non-steroidal anti-inflammatory drugs

Magnetic nanoparticles (MNPs), prepared via thiol-ene click chemistry and containing both diol and octadecyl groups, are shown to possess both hydrophobic and hydrophilic functionalities. They display excellent dispersibility in water and also are capable of extracting non-steroidal anti-inflammatory drugs (NSAIDs) from water samples. The MNPs can be magnetically separated, and the NSAIDs eluted with acetonitrile-water (9:1, v:v) and submitted to high performance liquid chromatographic analysis. Extraction variables, such as the kind of ion-pairing reagents, amount of MNPs, pH of sample solution, extraction and desorption time, volume of desorption solvent and salt addition, were optimized. Under optimum conditions, the method has a wide analytical range (from 5 to 800 ng∙mL‾1), good reproducibility with intra-day and inter-day relative standard deviations of <19.2 % (for n = 6), and low detection limits of 0.32 to 1.44 ng∙mL‾1 for water samples. The results demonstrate that the material possesses good water compatibility, thus warranting ease of operation and good reproducibility.