Boronic acid-functionalized magnetic covalent organic frameworks based solid-phase extraction coupled with hydrophilic interaction chromatography-tandem mass spectrometry for the determination of trace gentamicin residues in milk.

Boric acid-functionalized magnetic covalent organic frameworks (FeO-TpBD-B) with large surface area and high porosity were prepared and applied for magnetic solid-phase extraction adsorbent of gentamicin from milk before UPLC-MS/MS detection. By utilizing a new HILIC chromatographic column with zwitterionic sulfoalkyl betaine stationary phase based on ethyl bridged hybrid particles (BEH), isomers of gentamicin (C, C, and C+C components). The developed methods demonstrated good linearity (R > 0.99), acceptable accuracy and good precision (<10 %), and low limit of quantitation (1.59 ng mL⁻ for C, 1.52 ng mL⁻ for C and 2.72 ng mL⁻ for C+C). In addition, this method has been effectively applied to the analysis of real milk samples.