文献类型：期刊文献

英文题名：Influence of Electrolyte Concentration on Single-Molecule Sensing of Perfluorocarboxylic Acids

作者：Yao, Xinyun[1,2];Song, Ning-Ning[3];Wang, Jia[3];Zhao, Xian[3];Cheng, Meng-Yuan[3];Zuo, Jiaqi[3];Qiu, Kaipei[1,3,4]

机构：[1]State Environm Protect Key Lab Environm Risk Asse, Shanghai, Peoples R China;[2]East China Univ Sci & Technol, Sch Chem & Mol Engn, Shanghai, Peoples R China;[3]East China Univ Sci & Technol, Shanghai Environm Protect Key Lab Environm Stand, Sch Resources & Environm Engn, Shanghai, Peoples R China;[4]Shanghai Inst Pollut Control & Ecol Secur, Shanghai, Peoples R China

年份：2021

卷号：9

外文期刊名：FRONTIERS IN CHEMISTRY

收录：;WOS:【SCI-EXPANDED(收录号:WOS:000685470000001)】；

基金：This work was supported by National Natural Science Foundation of China (Grant No. 21972041, 22006037), Shanghai Sailing Program (Grant No. 19YF1410400), and State Key Laboratory of Pollution Control and Resource Reuse Foundation (Grant No. PCRRF20001).

语种：英文

外文关键词：single-molecule sensing; perfluorocarboxylic acids; electrolyte concentration; nanopore electrochemistry; identification and quantification

摘要：Perfluorocarboxylic acids (PFCAs) are an emerging class of persistent organic pollutants. During the fabrication process, it is unavoidable to form PFCA homologs or isomers which exhibit distinct occurrence, bioaccumulation, and toxicity. The precision measurement of PFCAs is therefore of significant importance. However, the existing characterization techniques, such as LC-MS/MS, cannot fully meet the requirement of isomer-specific analysis, largely due to the lack of authentic standards. Single-molecule sensors (SMSs) based on nanopore electrochemistry may be a feasible solution for PFCAs determination, thanks to their ultra-high spatiotemporal resolutions. Hence, as a first step, this work was to elucidate the influence of electrolyte concentration on the four most critical indicators of nanopore measurements, and furthermore, performance of nanopore SMSs. More specifically, three of the most representative short-chain PFCAs, perfluoropentanoic acid (PFPeA), perfluorohexanoic acid (PFHxA) and perfluoroheptanoic acid (PFHpA), were adopted as the target analytes, aerolysin nanopore was employed as the sensing interface, and 2, 3 and 4 M KCl solutions were used as electrolytes. It was found that, when the concentration of KCl solution increased from 2 to 4 M, the conductance of aerolysin nanopore increased almost linearly at a rate of 0.5 nS per molar KCl within the whole voltage range, the current blockade of PFPeA at -50 mV increased from 61.74 to 66.57% owing to the enhanced steric exclusion effect, the maximum dwell time was more than doubled from 14.5 to 31.5 ms, and the barrier limited capture rate increased by 8.3 times from 0.46 to 3.85 Hz. As a result, when using 4 M KCl as the electrolyte, over 90% of the PFPeA, PFHxA and PFHpA were accurately identified from a mixed sample, and the calculated limit of detection of PFPeA reached 320 nM, more than 24 times lower than in 2 M KCl. It was thus clear that tuning the electrolyte concentration was a simple but very effective approach to improve the performance of nanopore SMSs for PFCAs determination.