Hafeez Sumbul, Khanam Aysha, Cao Han, Chaplin Brian P, Xu Wenqing
Department of Civil and Environmental Engineering, Villanova University, Villanova, Pennsylvania 19085, United States.
Department of Chemical Engineering, University of Illinois at Chicago, 929 W. Taylor St., 14, Chicago, Illinois 60607, United States.
Environ Sci Technol Lett. 2024 Aug 5;11(8):871-877. doi: 10.1021/acs.estlett.4c00557. eCollection 2024 Aug 13.
This study developed a novel molecularly imprinted polymer (MIP) that is both conductive and redox-active for directly quantifying perfluorooctanoic acid (PFOA) electrochemically. We synthesized the monomer 3,4-ethylenedioxythiophene-2,2,6,6-tetramethylpiperidinyloxy (EDOT-TEMPO) for electropolymerization on a glassy carbon electrode using PFOA as a template, which was abbreviated as PEDOT-TEMPO-MIP. The redox-active MIP eliminated the need for external redox probes. When exposed to PFOA, both anodic and cathodic peaks of MIP showed a decreased current density. This observation can be explained by the formation of a charge-assisted hydrogen bond between the anionic PFOA and MIP's redox-active moieties (TEMPO) that hinder the conversion between the oxidized and reduced forms of TEMPO. The extent of the current density decrease showed excellent linearity with PFOA concentrations, with a method detection limit of 0.28 ng·L. PEDOT-TEMPO-MIP also exhibited high selectivity toward PFOA against other per- and polyfluoroalkyl substances (PFAS) at environmentally relevant concentrations. Our results suggest electropolymerization of MIPs was highly reproducible, with a relative standard deviation of 5.1% among three separate MIP electrodes. PEDOT-TEMPO-MIP can also be repeatedly used with good stability and reproducibility for PFOA detection. This study provides an innovative platform for rapid PFAS quantification using redox-active MIPs, laying the groundwork for developing compact PFAS sensors.
本研究开发了一种新型分子印迹聚合物（MIP），它具有导电性和氧化还原活性，可直接电化学定量全氟辛酸（PFOA）。我们以PFOA为模板，在玻碳电极上合成了用于电聚合的单体3,4-乙撑二氧噻吩-2,2,6,6-四甲基哌啶氧基（EDOT-TEMPO），简称为PEDOT-TEMPO-MIP。这种具有氧化还原活性的MIP无需外部氧化还原探针。当暴露于PFOA时，MIP的阳极峰和阴极峰电流密度均降低。这一现象可通过阴离子PFOA与MIP的氧化还原活性部分（TEMPO）之间形成电荷辅助氢键来解释，该氢键阻碍了TEMPO氧化态和还原态之间的转化。电流密度降低的程度与PFOA浓度呈现出良好的线性关系，方法检出限为0.28 ng·L。在环境相关浓度下，PEDOT-TEMPO-MIP对PFOA相对于其他全氟和多氟烷基物质（PFAS）也表现出高选择性。我们的结果表明，MIP的电聚合具有高度可重复性，三个独立的MIP电极之间的相对标准偏差为5.1%。PEDOT-TEMPO-MIP还可重复使用，对PFOA检测具有良好的稳定性和可重复性。本研究为使用具有氧化还原活性的MIP进行快速PFAS定量提供了一个创新平台，为开发紧凑型PFAS传感器奠定了基础。
