A Covalent Organic Framework-Derived Hydrophilic Magnetic Graphene Composite as a Unique Platform for Detection of Phthalate Esters from Packaged Milk Samples

The development of functional nanocomposites based on covalent organic framework (COF) is still highly important. In this work, a novel COF-functionalized hydrophilic magnetic graphene (magG@PDA@TbBd) was prepared through a facile and efficient route and applied as a unique magnetic solid-phase extraction matrix for phthalate esters analysis. The obtained magG@PDA@TbBd exhibited excellent water dispersibility, large surface area, strong magnetic response, regular mesoporous structure and strong π–π electron system. Based on these properties, the newly prepared composite displayed outstanding reusability and potential performances on phthalates analysis with good linearity (50–8000 ng mL−1) and reliable recoveries (91.4–105.2%). Limit of detection (LOD) varied from 0.004 ng mL−1 to 0.02 ng mL−1, and relative standard deviation (RSD) for intra-day and inter-day were less than 4.4% and 6.7%, respectively. More interestingly, the newly obtained magG@PDA@TbBd was utilized to analyze 9 PAEs in packaged milk samples. This work may open-up a direction in design and construction of functionalized COF-derived composites.