Metal-Organic Framework@Microporous Organic Network as Adsorbent for Solid-Phase Microextraction.

The practical applications of moisture sensitive metal-organic frameworks (MOFs) in the extraction technique are faced with avoided challenges related to competitive adsorption and hydrostability. The target analytes cannot be effectively extracted under humid conditions because of the competitive moisture adsorption and/or framework structure collapse of MOFs. In this Letter, metal-organic framework (MOF)@microporous organic network (MON) hybrid materials were explored for the first time as fiber coatings for solid-phase microextraction (SPME). Microporous materials with a hydrophobic surface was formed by coating the MOFs (MIL-101 and MOF-5) with MON through a sonogashira coupling reaction. MON acted as a hydrophobic "shield" to hinder the competitive moisture adsorption and improve moisture resistance and stability of the fiber. The sorbent exhibited higher enrichment factors (1215-3805) toward PAHs than other analytes in the water samples. An SPME method using MOF@MON-based fiber was developed to quantitatively determine PAHs. The proposed method was successfully applied to analyze PAHs in environmental water, particulate matter (PM2.5), and food samples. A successful technique is proposed to chemically control MOF for applications in solid-phase sorption-based extraction techniques.