Mechanochemical synthesis ionic covalent organic frameworks/cotton composites for pipette tip solid-phase extraction of domoic acid in seafood.

Pipette tip solid-phase extraction (PT-SPE) as a miniaturized solid-phase extraction technique have a wide range of applications in the field of sample pretreatment. In this study, ionic covalent organic frameworks@cotton (iCOF@cotton) were facilely synthesized by mechanochemical grinding method only in half an hour, and used as the adsorbents of PT-SPE. The synthesized iCOF@cotton not only had high specific surface area, suitable pore structure and cationic charge groups of iCOF that can extract polar targets quickly, but also reduced the problem of high back pressure of PT-SPE by the addition of cotton, thus accelerating extraction time. Combined with high performance liquid chromatographic tandem mass spectrometry (HPLC-MS/MS), an efficient and sensitive method was established for detection of domoic acid (DA, a toxin produced by algae). Under the optimal conditions, the proposed analysis method displayed excellent analytical performance, including broad range of linearity (10–1000 pg mL−1), low limit of detection (LOD, 5 pg mL−1), high correlation coefficient (0.9993), satisfactory precision (RSDs ≤6.4 %). In addition, the developed method was applied to the detection of DA in marine samples, and detected trace DA (18.6 pg mL−1) with satisfactory recovery (85.7%–107.2 %). The above results indicated that the prepared iCOF@cotton have great potential as the adsorbents for PT-SPE. [Display omitted] • Ionic covalent organic frameworks@cotton were fast and conveniently synthesized by mechanochemistry methods. • Ionic covalent organic frameworks have abundant cationic charge groups and high adsorption capacity for domoic acid. • The cotton effectively reduced high back pressure in the pipette tip solid-phase extraction. • The method was successfully applied to the enrichment of domoic acid in marine samples. [ABSTRACT FROM AUTHOR]