Amino-functionalized covalent organic framework for the effective capture of neonicotinoids from honey, beverages and...

An amino-functionalized pyrazine-based highly conjugated covalent organic framework (NH₂-PyCOF) was synthesized via a post-synthetic modification strategy and applied as an adsorbent for the solid-phase extraction (SPE) of four neonicotinoid insecticides (NTIs) in honey, beverage and water samples. NH₂-PyCOF combines a highly conjugated pyrazine skeleton with multiple amino sites, which not only enhances its hydrophilicity but also provides multiple interaction sites, including hydrogen-bonding and π-π stacking sites. When NH₂-PyCOF-based SPE was coupled with HPLC-MS, the method demonstrated low detection limits (0.025-0.10 ng mL^-1 for peach beverage samples, 0.01-0.03 ng mL^-1 for water samples and 0.20-0.80 ng g^-1 for honey samples) and satisfactory recoveries (86.0%-111%) with relative standard deviations below 8.4%. The NH₂-PyCOF-SPE-HPLC-MS method exhibits exceptional sensitivity and reproducibility, providing a reliable and efficient approach for monitoring trace NTI residues in complex matrices.