Abstract
The pillared-layer Zn-triazolate metal-organic framework (CIM-81) was synthesized, characterized, and used for the first time as a sorbent in a dispersive micro-solid phase extraction method. The method involves the determination of a variety of personal care products in wastewaters, including four preservatives, four UV-filters, and one disinfectant, in combination with ultra-high performance liquid chromatography and UV detection. The CIM-81 MOF, constructed with an interesting mixed-ligand synthetic strategy, demonstrated a better extraction performance than other widely used MOFs in D-µSPE such as UiO-66, HKUST-1, and MIL-53(Al). The optimization of the method included a screening design followed by a Doehlert design. Optimum conditions required 10 mg of CIM-81 MOF in 10 mL of the aqueous sample at a pH of 5, 1 min of agitation by vortex and 3 min of centrifugation in the extraction step; and 1.2 mL of methanol and 4 min of vortex in the desorption step, followed by filtration, evaporation and reconstitution with 100 µL of the initial chromatographic mobile phase. The entire D-µSPE-UHPLC-UV method presented limits of detection down to 0.5 ng·mL−1; intra-day and inter-day precision values for the lowest concentration level (15 ng·mL−1)-as a relative standard deviation (in %)-lower than 8.7 and 13%, respectively; average relative recovery values of 115%; and enrichment factors ranging from ~3.6 to ~34. The reuse of the CIM-81 material was assessed not only in terms of maintaining the analytical performance but also in terms of its crystalline stability.
Highlights
Humans and living organisms are exposed to an increasing amount of emerging pollutants, with clear health issues associated [1,2]
CIM-81 is obtained through a solvothermal synthesis using DMA as a solvent
The Metal-organic frameworks (MOFs) exhibits good thermal and chemical stability in water and in organic solvents [35,36], and it is obtained in a good yield
Summary
Humans and living organisms are exposed to an increasing amount of emerging pollutants, with clear health issues associated [1,2] Their low levels in environmental samples (still risky even at those levels) [1] undoubtedly require the utilization of proper analytical sample preparation techniques together with an adequate chromatographic analysis. Molecules 2019, 24, 690 the Green Analytical Chemistry (GAC) [3] have pushed the scientific community to develop environmental-friendly strategies Within this context, the main efforts have been devoted to the miniaturization of sample preparation approaches, together with research on novel and greener solvents and/or sorbents [4,5]. D-μSPE is probably the simpler approach, as it does not require the use of additional materials such as sorbents for its performance, and it ensures a high strength of analyte-sorbent interactions
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