RESUMO
In this work, electrospinning and hydrothermal methods were employed to synthesize an innovative 3D Co3O4/C@HCNFs nanocomposite as the sorbent. It was then used in a packed sorbent microextraction system for parabens analysis in human blood samples, followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The coaxial electrospun core-shell nanofibers mat was stabilized and carbonized to produce the hollow carbon nanofibers (HCNFs) substrate. A coating of cobalt carbonate hydroxide nanopolks was then grown on the HCNFs through hydrothermal synthesis. Ultimately, some of the nanopolks were converted to ZIF-67 by pouring the mat into a warm solution of 2-methyl imidazole and heat-treated into porous Co3O4/C afterward. X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) analyses were used to characterize the produced nanocomposite. The effective parameters of the adsorption and desorption steps were optimized by a central composite design. The figures of merit were evaluated under optimal conditions. The linear range of parabens was obtained between 0.5-500.0 ng ml-1 with R2 ≥ 0.9980. The detection limits of the method were between 0.1 and 0.2 ng ml-1. The intra-day and inter-day precisions were less than 4.3%. Relative recoveries between 92.0% and 109.3% were achieved. The findings demonstrated the eligible performance of the method.