A Benign Protocol for the Simultaneously Specific Extraction of Acidic and Basic Pollutants in Environmental Samples...

Simultaneously specific extraction of acidic and basic organic pollutants (A&BOPs) is significant in the enhancement of analytical efficiency but is challenging due to their strong and opposite polarity. In the current study, a benign protocol was proposed for the simultaneously selective capture of A&BOPs with the assistance of electric field. Selecting 4-nitrophenol and 2,4-dinitroaniline as the model templates of acidic and basic compounds, respectively, two molecularly imprinted monolith (MIM)-based microelectrodes (MEs) were in situ synthesized and acted as the anode and cathode of the electro-assisted solid-phase microextraction (EA/SPME) technique, respectively. Results revealed that the application of an electric field during the extraction procedure significantly improved the specific recognition capability toward templates and their structural analogues. For phenols, the imprinted factors (α) were increased from 1.37 to 1.45 (absence of electric field) to 2.76-2.92 (presence of electric field) and enhanced from 1.47 to 1.69 to 2.35-2.85 for anilines. Studies about extraction behaviors revealed that the specific recognition of imprinting materials and electric field force co-contributed to the simultaneously selective capture of phenols and anilines. Under the beneficial extraction parameters, the practicality of MIM@MEs-EA/SPME was well demonstrated by simultaneously selective extraction of trace phenols and anilines in various environmental water and soil samples prior to chromatographic analysis. The present work not only supplies a feasible strategy for the simultaneously and effectively specific extraction of A&BOPs but also expands the application scopes of EA/SPME and MIM.