Detection of Toxic Polychlorinated Biphenyls by Nanoporous Metal–Organic Frameworks

As a class of persistent organic pollutants (POPs), polychlorinated
biphenyls (PCBs) are highly hazardous to the ecosystem, and their
effective and facile detection is of high importance. Herein, we present
two nanoporous metal–organic frameworks (MOFs), (Me2NH2)­[In­(CPTTA)]·(DMF)1.5(H2O)3.5 (BUT-174) and (Et2NH2)­[In­(CPTTA)]·(DEF)­(H2O)3 (BUT-175), constructed by In3+ ions
and the aromatic-rich tetratopic carboxylate ligands, 5′-(4-carboxylatophenyl)-[1,1′:3′,1″-terphenyl]-3,4′′,5-tricarboxylate
(CPTTA4–), which exhibit highly efficient turn-down
fluorescence response toward 12 PCBs, especially for three highly
toxic non-ortho-substituted PCBs (PCB-77, -126, and
-169) with the so-called “coplanar” molecular configuration
in various solvents with the limits of detection (LODs) down to the
ppb level owing to the inner filter effect between MOFs and PCBs.
In addition, the MOFs show high sensing selectivity toward PCBs over
many relevant interferents, including hexabromocyclododecane (HBCD),
decabromodiphenyl oxide (DBDPO), perfluorobutanoic acid (PFBA), and
perfluorooctanoic acid (PFOA), as well as good recyclability and stability.
It is demonstrated by this work that structurally well-defined MOFs
could be promising sensory materials for the detection of highly toxic
PCBs in a facile way.