Porous pyrene-based HOF-102 coating for solid-phase microextraction of nitroaromatic compounds in beverage samples.

Abstract

A porous pyrene-based hydrogen-bonded organic framework (HOF-102) was evaluated as a coating for direct-immersion solid-phase microextraction (DI-SPME) of nitrobenzene (NB) and three nitrotoluene isomers in beverage matrices. Single-factor experiments followed by a Box-Behnken design were used to optimize the extraction conditions. Coupling the HOF-102-coated fiber with GC-MS provided linear ranges of 0.2-1000 µg L-1 for NB, o-NT, and m-NT and 0.5-1000 µg L-1 for p-NT, with limits of detection of 0.05-0.11 µg L-1. Intra-day, inter-day, and fiber-to-fiber RSDs were 1.9-5.4%, 2.9-7.9%, and 4.6-9.7%, respectively. HOF-102 gave higher extraction responses than the four reference coatings tested and retained approximately 90% of its initial response after 70 extraction-desorption cycles. The analyte-dependent signal enhancement factors ranged from 1778 to 2935. DFT calculations were performed on the isolated analytes to characterize their electronic-structure descriptors, including frontier molecular orbitals and electrostatic potential distributions. Spike recoveries in milk, orange juice, tea drink, and mineral water ranged from 81.5% to 110.7%. These results demonstrate the potential of HOF-102 as a robust porous coating for DI-SPME of nitroaromatic compounds.

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