MOF-199-based coatings as SPME fiber for measurement of volatile organic compounds in air samples: Optimization of in situ deposition parameters

In this study MOF-199-based solid-phase microextraction coating was synthesized using an in situ solvothermal method on a stainless steel substrate. The effects of solvent, metal salt, chemical modulator, and batch composition on the physicochemical characteristics of the MOF-199 coating were studied. The thickness of the MOF-199 coating increased by 18% when 15.2 mmol of acetic acid was used as an additive. Using 99.9% butanol as the solvent improved homogeneity (smaller crystallite size) of the MOF coating and decreased coating thickness by 7.5 times compared to those of 75% ethanol. Using Cu(OAc)(2)center dot H2O as the metal precursor did not lead to the growth of the MOF-199 layer on stainless steel cores. Whilst the use of Cu(NO3)(2)center dot 3H(2)O allowed to obtain 6-, 21-, 34-, 62-, 94-and 105 mu m MOF-199 SPME coatings. Responses of 7 volatile organic compounds by 34-mu m and 62-mu m MOF-199-based fibers were 1.2-8.5 times higher than those of commercial PDMS/DVB. The method developed for the quantification of BTEX in the air was characterized by high linearity (R-2 = 0.9909-0.9993), low limits of detection (0.03-0.09 mu g/m3), and quantification (0.09-0.31 mu g/m(3)), high repeatability (1.0-6.4%) and reproducibility (4.5-8.0%). The spike recoveries ranged from 73% to 108%.

Automated summary

In this study, a solid-phase microextraction coating based on MOF-199 was synthesized on a stainless steel substrate using an in situ solvothermal method. The factors affecting the physicochemical characteristics of the MOF-199 coating, such as solvent, metal salt, chemical modulator, and batch composition, were investigated. The thickness of the MOF-199 coating increased with the addition of acetic acid and decreased significantly when using butanol as the solvent compared to ethanol. Different metal precursors resulted in varying thicknesses of the MOF-199 coating.