RESUMO
This paper describes the synthesis of novel molecularly imprinted magnetic nano-beads for the selective extraction (MISPE) of zearalenone mycotoxin in river and tap waters and further analysis by high-performance liquid chromatography (HPLC) with fluorescence detection (FLD). A semi-covalent imprinting approach was achieved for the synthesis of the molecularly imprinted polymers (MIP). The nanoparticles were prepared by covering the starting Fe3O4 material with a first layer of tetraethyl orthosilicate (TEOS) and then with a second layer using cyclododecyl 2-hydroxy-4-(3-triethoxysilylpropylcarbamoyloxy) benzoate. The last was used with a dual role, template and functional monomer after the extraction of the template molecule. The material was characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopies (FT-IR). The solid phase extraction was optimized in all the steps: loading, washing and elution. The optimal conditions allowed the determination of zearalenone in trace levels of 12.5, 25 and 50 µg L-1 without significant differences between the fortified and found level concentrations.
Assuntos
Nanopartículas de Magnetita , Impressão Molecular , Zearalenona , Impressão Molecular/métodos , Polímeros Molecularmente Impressos , Espectroscopia de Infravermelho com Transformada de Fourier , Polímeros/química , Extração em Fase Sólida/métodos , Cromatografia Líquida de Alta Pressão/métodos , AdsorçãoRESUMO
This work reports the optimization of a method using Molecularly Imprinted Polymers (MIPs) for the simultaneous determination of zearalenone and alternariol mycotoxins. The method was optimized using a chemometric approach where in the optimized conditions, the cartridges with a mixture (50:50, w/w) of both MIPs, were loaded with 30 mL of sample, washed with 2 mL of ACN/water (20/80, v/v) and eluted with 2.5 mL of trifluoroacetic acid/MeOH (3/97, v/v). The extracts were analyzed by HPLC coupled to a fluorescence detector (FLD). The optimized method has been applied and validated to the analysis of the mycotoxins in maize, sunflower and olive oils samples with a limit of detection of 5 and 2 µg kg-1, respectively. Recoveries were in the range of 94 % to 108 % (RSD < 6 %) for zearalenone and 92 % to 113 % (RSD < 5 %) for alternariol. The results were confirmed by HPLC-MS/MS.