Fabrication of polyethyleneimine modified magnetic microporous organic network nanosphere for efficient enrichment of non-steroidal anti-inflammatory drugs from wastewater samples prior to HPLC-UV analysis.

Development of novel functionalized adsorbents for efficient magnetic solid phase extraction (MSPE) is essential for promoting their versatile applications in sample pretreatment. Herein, we report the fabrication of a new polyethyleneimine-600 decorated magnetic microporous organic network nanosphere (FeO@MON-PEI) for effective MSPE of trace non-steroidal anti-inflammatory drugs (NSAIDs) from different water samples. The core-shelled FeO@MON-PEI integrates the synergistic effects of FeO, MON and PEI, providing facile and effective extraction to NSAIDs via multiple hydrogen bonding, π-π and hydrophobic interactions. The inner MON shell employs π-π and hydrophobic interaction sites and the outer PEI-600 coat acts as the hydrogen bonding doner/receptor, which affords good extraction performance for NSAIDs. Under optimal conditions, the FeO@MON-PEI-MSPE-HPLC-UV method gives wide linear range (0.14-400 μg L), low limits of detection (0.042-0.149 μg L), good precisions (intra-day and inter-day RSDs < 4.5%, n = 6), and large enrichment factors (97.0-98.2). Extraction mechanisms and selectivity of FeO@MON-PEI are evaluated in detail. Moreover, FeO@MON-PEI is successfully applied to enrich the trace NSAIDs in different water samples with the concentrations of 0.7 and 0.8 μg L for 1-naphthylacetic acid, 0.5 and 0.1 μg L for naproxen as well as 0.7 μg L for ibuprofen, respectively. The developed method not only affords a novel and efficient magnetic adsorbent for NSAIDs in aqueous media at trace level, but also provides a new strategy for the rational design and synthesis of multiple functionalized MON composites in sample pretreatment.