RESUMO
In this study, a low-cost microfluidic device from polymethyl methacrylate was fabricated by laser engraving technique. The device is consisted of a central chip unit with an aligned microchannel. Both sides of the engraved microchannel were sandwiched by two synthesized sheets from polyamide/titania (PA/TiO2) hollow nanofibers as extractive phases. The inlet and outlet of the device were connected to the polyether ether ketone tubes, while a peristaltic pump was used to deliver both sample and desorbing solvent through the microchannel. The recorded scanning electron microscopy images from the surface of the synthesized PA/TiO2 nanofibers, exhibit a good degree of homogeneity and porosity throughout their structures. Also, the presence of titanium was indicated by the energy dispersive X-ray analysis, while the recorded Fourier transform infrared spectra confirmed their chemical structures. The addition of titania in the composition of polyamide nanofibers, not only improved the mechanical stability of the extractive phase but also enhanced its extraction capability. The major parameters associated with the extraction performance were studied and eventually the method was validated by the use of a gas chromatography-mass spectrometry. The limits of detection for the selected triazines were between 0.01 and 0.03ngmL-1, while the limits of quantification ranged from 0.04 to 0.1ngmL-1. In addition, the interday and intraday reproducibility (RSD%) were lower than 6.6% (n=3). The calibration graph for atrazine was linear in the range of 0.2-50ngmL-1 while two linear ranges for ametryn and terbutryn (0.1-10 and 20-500ngmL-1) were achieved. Relative recoveries were between 89 and 98% with the regression coefficient range of 0.9969-0.9991.