Spin-column micro-solid phase extraction of chlorophenols using MFU-4l metal-organic framework

A novel metal-organic framework called MFU-4 l was synthesized from ZnCl₂ and 1H-1,2,3-triazolo[4,5-b][4',5'-i])dibenzo[1,4]dioxin. MFU-4 l was characterized and is shown to be a viable sorbent for spin-column micro-solid phase extraction of 4-chlorophenol, 2,3-dichlorophenol, 2,4-dichlorophenol, and 2,4,6-trichlorophenol. Following extraction and elution with methanol, the chlorophenols were quantified by a GC-MS instrument. Various parameters affecting adsorption and desorption were optimized by the one variable at-a-time method. The main feature of the utilized metal-organic framework is its outstanding performance in ultratrace extraction of the target analytes due to the different amino groups existed in the linker structure. Under optimal conditions, the calibration plots are linear in the 0.5-400 μg kg^-1 concentration range for water samples, and from 1.0-400 μg kg^-1 for soil samples. The respective limits of detection are 0.10 and 0.50 μg kg-1 for water and soil samples, respectively. On top of that, limits of detections are lower than 0.10 and 0.50 μg Kg^-1 for water and soil samples, respectively. Inter-day and intra-day relative standard deviations were in the range of 4.4-7.8% for the selected chlorophenols. Preconcentration factors are in the range of 26.3-29.6 for aqueous samples. The method was used to analyze soil and environmental water samples. Graphical abstractSchematic representation of spin-column micro-solid phase extraction of chlorophenols using the MFU-4 l metal-organic framework.