Electric field-reinforced solid phase microextraction based on anion-exchange monolith for efficient entrapment of anions in aqueous and wine samples.

In the present work, a new strategy based on electric field-reinforced solid phase microextraction (ER-SPME) for the analysis of trace inorganic anions in aqueous and wine samples was proposed. In this connection, anion-exchange monolith (AEM) was in-situ synthesized on the surface of stainless steel wire and employed as the adsorbent of ER-SPME. Variable electric fields were applied during the adsorption and desorption durations to improve the entrapment performance towards studied anions. Results revealed that the application of electric fields not only accelerated the extraction process, but also enhanced the extraction efficiencies (increased by 59-121% compared with without exertion of electric field). Under the selected extraction parameters, sensitive method with wide linear ranges (5.0-500 µg/L for BrO and 0.10-500 µg/L for other anions), low limits of detection (0.030-2.5 µg/L) and satisfactory precision (RSDs below 10%) was established by the combination of AEM/ER-SPME with ion chromatography with conductivity detector. The developed approach was successful used to quantify trace investigated anions in various aqueous and wine samples, and the fortified recoveries varied from 83.2 to 115%. At the same time, related adsorption and desorption mechanism under the electric field was inspected.