β‐Ketoenamine‐linked covalent organic framework absorbent for online micro‐solid phase extraction of trace levels bisphenols in plastic samples

Abstract

Covalent organic frameworks with tunable porous crystallinity and outstanding stability have exhibited fascinating pretreatment performance as ideal extraction media. Herein, the β-ketoenamine-linked TpPa-1 synthesized by 1,3,5-triformylphloroglucinol and paraphenylenediamine was employed as the absorbent for online micro-solid phase extraction of trace bisphenols combined with high-performance liquid chromatography detection. A series of characterizations indicated that the TpPa-1 possessed large surface areas, high stability, and hydrophobicity. The main experimental parameters affecting the extraction efficiency were optimized in detail. Compared with four commercial sorbents, the TpPa-1 exhibited superior enrichment capacity for extracting bisphenols. Under the optimum conditions, the established method demonstrated a wide linear range and high sensitivity with the limit of detection ranging from 0.05-0.06 μg/L. Furthermore, the developed method was successfully applied to determine bisphenols in plastic samples. Bisphenol A was actually detected in a transparent box with a concentration of 0.31 μg/g, and the recoveries of the four bisphenols in the plastic samples were 80.5-116% with the relative standard deviation less than 9.2%. Such performance was attributed to recognition affinity, including the ππ affinity, hydrophobic effect, and hydrogen bond. These results demonstrated that TpPa-1 possessed great potential to be an excellent pretreatment medium for online separation and analysis of trace analytes in complex samples.

Exploration of porous imine‐based covalent organic framework for solid‐phase extraction of five trace sulfonamides in food samples

“…For example, Spherical COF synthesized by Wu et al was used to efficiently eliminate complex matrix interference to enrich and quantify aryl organophosphate esters in mouse serum and tissues [15]. Beta-ketoenamine-linked TpPa-1 synthesized by Zhang et al exhibits good enrichment capacity for bisphenols in plastic samples [16]. The effective adsorption of drug residues by COFs has been confirmed in many ways.…”

“…Beta‐ketoenamine‐linked TpPa‐1 synthesized by Zhang et al. exhibits good enrichment capacity for bisphenols in plastic samples [16]. The effective adsorption of drug residues by COFs has been confirmed in many ways.…”