Fabrication and evaluation of magnetic activated carbon as adsorbent for ultrasonic assisted magnetic solid phase dispersive extraction of bisphenol A from milk prior to high performance liquid chromatographic analysis with ultraviolet detection.

In the present study, the impregnation of a micro - meso porous activated carbon with magnetite (Fe3 O4 ) was successfully achieved by sonication and the magnetic activated carbon prepared (Bmi) was evaluated as a new adsorbent for ultrasonic assisted magnetic solid phase dispersive extraction of Bisphenol A (BPA) from cow milk and human breast milk samples, prior to the determination by HPLC with UV detection. The prepared Bmi was characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM). The effect of pH on adsorption, initial concentration, contact time and desorption were studied. The main experimental parameters influencing extraction efficiency of BPA, such as type and amount of the adsorbent, sample amount, type of desorption solvent, time of adsorption and desorption, type of precipitation solvent, were investigated and optimized. Under the optimal extraction conditions the absolute recovery of BPA was 81% and 95% in cow milk and human breast milk samples, respectively. Good linearity was observed in the investigated concentration range of 2.5μgkg-1 -5000μgkg-1 (R2 =0.9997). Limit of detection (LOD) was 0.75μgL-1 , which is in accordance with the specific migration limit (SML) established by the European Union, and limit of quantification (LOQ) was 2.5μgL-1 . Within-day and between-day recoveries ranged from 91.4% to 98.6% and 89.1% to 99.4% respectively and the RSDs were less than 3.7%. Due to the excellent magnetic behavior of Bmi the proposed method was shown to be simple and rapid. Besides these, this method is sensitive, low cost, efficient and environmentally friendly.