β-cyclodextrin-functionalized magnetic graphene oxide for the efficient enrichment of bisphenols in milk and milk...

In this work, β-cyclodextrin-functionalized magnetic graphene oxide (NiFe₂O₄@GO@β-CD) was synthesized and employed as magnetic solid-phase extraction adsorbent for the extraction of bisphenols before high performance liquid chromatography analysis. The modification of β-cyclodextrin could enhance the adsorption performance of NiFe₂O₄@GO@β-CD towards bisphenols through the host-guest interaction and hydrogen-bond interaction. Under the optimal conditions, good linearities between peak area and concentration of bisphenols (1 - 300 μg L^-1, r ≥ 0.9989) were obtained with the limits of detection (S/N = 3) in the range of 0.050 - 0.10 μg L^-1. The recoveries of bisphenols in milk and milk packaging ranged from 78.0% to 101.6%. Moreover, NiFe₂O₄@GO@β-CD showed stable chemical properties and good reusability with the recoveries of bisphenols remained above 80.0% after 12 MSPE cycles. The adsorption characteristics of NiFe₂O₄@GO@β-CD towards bisphenols fitted well with the pseudo-second-order kinetic model and Langmuir model. The hydrogen-bond interaction, π-π interaction, host-guest interaction and electrostatic interaction between sorbent and bisphenols played important role during the adsorption process. The developed method showed potential applications for the analysis of trace bisphenols in milk and milk packaging.