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

Abstract

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. The polymerization reaction was carried out in the aqueous phase due to the hydrophilicity of HEMA and nanoparticles. The effect of the incorporation of the magnetic and carbon nanoparticles in the hydrophilic structure was evaluated. Therefore, variables affecting the stability and formation of the emulsion as well as the initiation and propagation of the polymerization were studied. The morphology of the obtained magnetic solids was characterized by SEM in order to show the differences in presence and absence of nanoparticles within the structure. Finally, the extraction performance of the hydrophilic solids was evaluated through the determination of anti-inflammatory drugs in aqueous 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.