A magnetic flower-like hollow vinyl-functionalized covalent organic framework nanocomposite for efficient enrichment of fifteen organophosphate tri-esters in environmental water samples.

BACKGROUND

Organophosphate tri-esters (tri-OPEs), widely used flame retardants, include alkyl-, halogenated-, and aryl-substituted types with distinct physicochemical properties. They may readily enter the ambient environment through volatilization, mechanical abrasion, and dissolution mechanisms occurring throughout the product lifecycle. To date, a range of monitoring methodologies incorporating sample pretreatment techniques have been developed to characterize the environmental distribution of tri-OPEs. However, given the distinct propertiesand molecular sizes of them, novel adsorptive materials developed for the simultaneous enrichment of multiple tri-OPEs arescarce.

RESULTS

This study facilely prepared a magnetic flower-like hollow vinyl-functionalized covalent organic framework nanocomposite (Fe3O4@HCOF-V) for simultaneous extraction of fifteen tri-OPEs. The hollow structure of Fe3O4@HCOF-V shared advantages of exposing more active sites of internal pore channels (140-351 mg g-1 adsorption capacity), shortening mass transfer pathway (10 min equilibrium), and accommodating multiple analytes (seven representative tri-OPEs). Molecular dynamics simulations suggested that Van der Waals forces dominated the adsorption mechanism. Furthermore, a general analytical method for the simultaneous detection of fifteen tri-OPEs based on magnetic solid phase extraction (Fe3O4@HCOF-V as absorbent) combined with UPLC-MS/MS was constructed. demonstrating low limits of detection (0.002-0.039 ng mL-1) and satisfactory spiked recoveries (74.5-123.7 %). Finally, the developed method was applied to analyze sixty-six samples, including source water, waste water, and tap water. The results revealed ubiquitous tri-OPE contamination in all environmental water samples, with wastewater exhibiting the highest concentrations.

SIGNIFICANCE: Our study extended the application of hollow COF in the field of sample pretreatment techniques and established a new paradigm for designing novel adsorbents toward simultaneous determination of multiple tri-OPEs. Furthermore, the developed analytical method demonstrated superior environmental monitoring capability, successfully applied for the mapping contamination profiles of tri-OPEs across diverse water environments.