New in situ solvothermally synthesized metal-organic framework MOF-199 coating for solid-phase microextraction of volatile organic compounds from air samples

The development of new solid-phase microextraction coatings has attracted more attention due to a limited number of commercially available fibers and their inherent shortcomings, such as low effectiveness when extracting polar compounds, poor selectivity, and possible swelling upon exposure to certain solvents. In recent years, an increased interest has developed in the synthesis of SPME fiber coatings based on metal-organic frameworks, which are promising due to their permanent porosity, large surface area, and high mechanical and thermal stability. The in situ solvothermal method was employed in developing a new MOF-199-based coating on an etched stainless-steel core. Optimal MOF-199 deposition on the core was achieved after 16 h reaction time using 96.5% (v/v) ethanol as a solvent. The extraction effectiveness of 25 volatile organic compounds from the air (at 150 and 15 mu g/m3) was evaluated using the newly developed SPME fiber with 22 +/- 3 mu m thickness and compared with two commercially available fibers - 65 mu m polydimethylsiloxane/divinylbenzene and 85 mu m Carboxen/polydimethylsiloxane. In comparison with polydimethylsiloxane/divinylbenzene, the MOF-199-based fiber provided 1.3-82.3 times higher responses of 16 volatile organic compounds, as obtained using gas chromatography-mass spectrometry. The responses of five volatile organic compounds obtained using the MOF-199-based fiber were in the same range as those from Carboxen/polydimethylsiloxane fiber. The newly developed fiber exhibited a greater selectivity toward low molecular volatile organic compounds. The extraction effectiveness of the MOF-199-based fiber for nine volatile organic compounds ranged between 35 and 88%, with distribution constants in the range of 9.4 x 104 to 127 x 104.

Automated summary

The development of new solid-phase microextraction coatings based on metal-organic frameworks shows promising features such as permanent porosity, large surface area, and high stability, allowing for effective extraction of volatile organic compounds with greater selectivity. The MOF-199-based coating outperforms commercially available fibers in Gas Chromatography-Mass Spectrometry detection by providing higher responses to volatile organic compounds.