Magnetic amino-functionalized hollow silica-titania microsphere as an efficient sorbent for extraction of pesticides in green and roasted coffee beans.

This study describes the synthesis and application of a magnetic amino-functionalized hollow silica-titania microsphere as a new sorbent for magnetic dispersive micro-solid phase extraction of selected pesticides in coffee bean samples. The sorbent was fully characterized by Fourier-transform infrared spectroscopy, field emission scanning electron microscopy, transition electron microscopy, energy-dispersive X-ray spectroscopy, and vibrating sample magnetometry techniques. Significant extraction parameters affecting the proposed method, such as extraction time, sorbent amount, sample solution pH, salt amount, and desorption conditions (desorption solvent and time) were investigated and optimized. All the figures of merits were validated in coffee bean samples under the matrix-matched calibration method. Linear dynamic ranges were 5-250 µg/kg with the determination coefficients (R2 ) > 0.9980. The limits of detection for the pesticides of chlorpyrifos, malathion, hexaconazole, and atrazine were 1.42, 1.43, 1.35, and 1.33 µg/kg, respectively. Finally, the method was successfully applied for the determination of the pesticides in green and roasted coffee bean samples, and the obtained recoveries were in the range of 74-113% for spiked samples. The prepared sorbent could be used for the magnetic dispersive micro-solid phase extraction of pesticides in the plant-derived food matrix.