A nanosized magnetic metal-organic framework of type MIL-53(Fe) as an efficient sorbent for coextraction of phenols and anilines prior to their quantitation by HPLC.

The authors describe the synthesis of a magnetic metal-organic framework (MOF) of type MIL-53(Fe) for coextraction of phenols and anilines from various environmental samples. A quick method for dispersive micro-solid phase extraction (D-μ-SPE) was developed for coextraction of the analytes 4-nitrophenol (4-NP), 4-chlorophenol (4-CP), 4-chloroaniline (4-CA), 1-amino-2-naphtol (1-A2N) and 2, 4-dichloroaniline (2, 4-DCA). The MOF was characterized by SEM, TEM, FT-IR, EDS, thermogravimetry, VSM and XRD. The method was optimized by response surface methodology combined with desirability function approach, specifically with respect to pH value of the sample, amount of sorbent, sorption time, salt concentration, sample volume, type and volume of the eluent, and elution time. Following elution with acetonitrile, the analytes were quantified by HPLC with photodiode array detection. Responses are linear in 0.1-2000 μg·L-1 concentration ranges. The limits of detection and relative standard deviations (for n = 5) are in the range of 0.03-0.2 μg·L-1 and 3.5-12.6%, respectively. Enrichment factors are 113, 61, 87, 144 and 114 for 4-NP, 4-CP, 4-CA, 1-A2N and 2,4-DCA, respectively. Recoveries from spiked samples ranged from 39.5 to 93.3%. The magnetic sorbent was successfully applied to the coextraction and determination of the analytes in river, rain and hookah water samples. Graphical abstract Schematic presentation for the synthesis of (a) Fe3O4 nanoparticles (NPs) and (b) Fe3O4@MIL-53(Fe). Fe3O4@MIL-53(Fe) was employed as a new nanosorbent in dispersive micro-solid phase extraction of phenols and anilines. The limits of detection are in the range of 0.03-0.2 μg·L-1.