Desenvolvimento de um disco de extração em fase sólida molecularmente impresso para a pré-concentração seletiva de tetraciclinas em amostras de água seguida de análise por HPLC-UV

Abstract

Emerging organic pollutants have caused great environmental concern. Among the most common pharmaceuticals, antibiotics are in focus, especially tetracyclines. The occurrence of these analytes at low levels makes necessary the use of selective and sensitive extraction techniques to enrich those compounds even in the presence of other concomitant interferents. In this way, it is thought that molecularly imprinted polymers (MIPs) fit perfectly to this application mainly due to their characteristics of selectivity and sensitivity. In addition, the use of 2-hydroxyethyl methacrylate (HEMA) and glycerol dimethacrylate (GDMA) during the synthesis increases the number of surface hydroxyl groups, which in turns makes the polymer more compatible with aqueous systems, since they enhance the hydrogen bonds between the water and surface hydroxyl groups, minimizing the interference of this solvent in the complex analyte-polymer. Thus, the objective of this project was to develop a MIP disk for the extraction of tetracyclines from water samples followed by the HPLC-UV analysis. The MIP was synthesized using oxytetracycline as template, methacrylic acid as functional monomer, ethylene glycol dimethacrylate as the cross-linker agent, 2,2’-azo-bis-iso-butyronitrile as radical initiator and HEMA and GDMA as hydrophilic monomers. The polymer was then compressed in a disk form of 40 mm of internal diameter and 2 mm of thickness and this system was used in solid-phase extraction procedures. The developed method showed great results for selective extraction of tetracyclines with good linearity, precision and accuracy showing limits of quantification of 5 µg L-1.