Metal organic framework/chitosan foams functionalized with polyethylene oxide as a sorbent for enrichment and analysis of bisphenols in beverages and water†
In this study, a metal organic framework/chitosan/polyethylene oxide foam (MOFs/CS/PEO foam) was successfully designed and fabricated, in which polyethylene oxide (PEO) acted as a porogen to increase the adsorption capacity of the MIL-53(Al)/CS foam. The inherent characters, e.g. strength and stability, of the modified foam were also significantly improved. As MIL-53(Al) exhibits the highest adsorption capacity in both computations and experiments among the candidates such as MIL-53(Al), MIL-53(Fe), MIL-101(Cr), MIL-101(Fe), UiO-66(Zr), and MIL-100(Fe), the MIL-53(Al)/CS/PEO foam was chosen as a sorbent to develop a vortex assisted solid phase extraction method for the first time. The efficient method was then successfully applied for the extraction of a trace amount of five bisphenols (bisphenol A, bisphenol B, bisphenol C, bisphenol AF and bisphenol F) in beverages and water with plastic containers, followed by high-performance liquid chromatography-fluorescence detection. A satisfactory result of methodology validation was obtained. Under the optimum conditions, the linear ranges were 0.1–20 μg L−1 with the correlation coefficient (r2) ranging from 0.9943 to 0.9977. The method detection limits were in the range of 0.019–0.065 μg L−1. And the recoveries ranged from 72.68 to 104.6% with relative standard deviations smaller than 9.1%. The proposed hybridization foam was durable and environmentally friendly, since it still maintained adsorption ability after being recycled ten times. The novel method proposed in this work could provide technical support in the fields of environmental protection and food safety.