Preparation, characterization and evaluation of hydrophilic polymers containing magnetic nanoparticles and amine-modified carbon nanotubes for the determination of anti-inflammatory drugs in urine samples.

Hydrophilic solids based on poly(2-hydroxyethyl methacrylate) (pHEMA) with embedded magnetic nanoparticles and amine-modified carbon nanotubes were synthesized by photopolymerization. For this purpose, an oil in water (O/W) emulsion with an aqueous/oil ratio of 60/40 was prepared where the polymerization reaction occurred in the aqueous phase due to the hydrophilicity of pHEMA and the selected nanoparticles. Variables affecting the stability and emulsion formation as well as the initiation and propagation of the polymerization were studied. The morphology of the obtained magnetic solids was characterized by SEM/EDAX in order to show the differences in presence and absence of nanoparticles within the structure. Finally, the synergic effect of both magnetic and carbon nanoparticles in the sorbent capacity of the final hydrophilic solids was evaluated through the determination of non-steroidal anti-inflammatory drugs (NSAIDs) in human urine samples. HPLC-UV was used as instrumental technique and detection limits ranged from 5 to 10 μg L-1. The precision was calculated both intra- and inter-solids (same and different synthesis batches) obtaining satisfactory RSD values of less than 13%, which indicated the robustness of the synthesis and the extraction procedure. Finally, a study with real and fortified urine samples was also carried out obtaining recovery values between 86% and 109% for target NSAIDs.