Covalent organic framework modified magnetic MXene for high enrichment and sensitive detection of polycyclic and sulfur-containing heterocyclic aromatic hydrocarbons in Chinese tea samples

Polycyclic aromatic hydrocarbons (PAHs) and sulfur-containing heterocyclic aromatic hydrocarbons (PASHs) are typical organic pollutants that are commonly present in the environment. Due to the continuous accumulation and transfer in the food chain, they will pose a significant threat to human life and health. In the present work, a new method was constructed with a ternary magnetic nanocomposite (Fe 0 @MXene@COF-LZU1) based magnetic solid phase extraction in combination with gas chromatography-tandem mass spectrometry (GC-MS/MS) for sensitive determination of them at trace level in Chinese tea samples. The magnetic nanomaterial Fe 0 @MXene@COF-LZU1 was synthesized via reduction and Schiff base reactions. The experimental results demonstrated that Fe 0 @MXene@COF-LZU1 had high adsorption ability and satisfactory chemical stability. Under the optimal experimental conditions, the method possessed good linearity in the concentration ranges of 0.0005 μgL −1 - 50 μg L −1 for dibenzothiophene (DBT), phenanthrene (PHE), fluoranthene (FLT) and pyrene (PYR), and 0.001 μg L −1 - 50 μg L −1 for 4-methyldibenzothiophene (4-MDBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT). The detection limits of this method were in the range of 0.014 ng L −1 -0.83 ng L −1 . The results of real samples demonstrated that the designed magnetic nanocomposite had a promising application prospect for measuring PAHs and PASHs.