Cucurbit[7]uril as a matrix solid-phase dispersion for the extraction of quaternary ammonium pesticides from vegetables and their determination using HPLC-UV.

Cucurbit[7]uril (Q[7]) was first used as a dispersant sorbent material in a matrix solid-phase dispersion for the simultaneous extraction of four quaternary ammonium pesticides from vegetables before analysis using high-performance liquid chromatography with UV detection. Q[7] exhibited a better selectivity and adsorption capability for these compounds, which is due to its ability to bind selectively organic molecules into its hydrophobic cavity and to form stable host-guest inclusion complexes. Various parameters affecting the extraction were investigated and optimized, such as sorbent/sample mass ratio, grinding time, rinsing and eluting conditions. Under optimized conditions, the proposed method exhibited a linear response in the concentration range of 1-100 μg·kg-1, satisfactory recoveries for eight types of vegetable samples (>70%), and high repeatability (RSD < 9.0%). The limits of quantification were between 0.43 μg·kg-1 and 0.99 μg·kg-1, which is nearly 50 times lower than the maximum residue limits established by the European Council.