Cellulose-coated CoFe2O4 nanoparticles as an adsorbent for extraction and preconcentration of bioactive compounds in vinegars

Abstract In this work, an extraction and preconcentration flow system using mini-column packed with cellulose-coated CoFe 2 O 4 was developed for the determination of bioactive compounds in vinegar samples by high-performance liquid chromatography with diode array detector (HPLC-DAD). The CoFe 2 O 4 nanoparticles were synthetized by a sonochemical method and coated with cellulose biopolymer. Both synthetized nanoparticles and nanocomposites were characterized employing the techniques of X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetry (TG) and Derivative Thermogravimetry (DTG). The flow system was optimized employing two-level full factorial design and Doehlert matrix, in which the established optimum conditions were: adsorbent mass of 254 mg, eluent concentration of 92% (v/v methanol/water) and sampling flow rate of 2.0 mL min −1 . In these conditions, the flow system allows the determination of 12 bioactive compounds with limits of detection and quantification that varied in the range of 0.0009–0.091 mg L −1 and of 0.0028–0.276 mg L −1 , respectively. Enrichment factors (EF) were in the range of 2.31–63.72. The proposed flow system was applied for the analysis of 24 vinegar samples of brands locally available in Salvador City, Bahia, Brazil.