PFAS detection combining electrochemistry at liquid/liquid immiscible interfaces and microfluidic devices

Context :

PFAS are manufactured chemical substances that contain the specific perfluoroalkyl chain (C_nF_2n+1) and polar/ionizable end groups. These substances are widely used in various industrial applications such as firefighting foams, food packaging, cookware, cosmetics and paints. Therefore, they have economical relevance that results in their widespread use and their release into the environment. It was uncovered that human exposure to PFAS is of high concern as these substances are connected with multiple toxicological issues such as cancer, diabetes, fertility and cardiovascular diseases (Jane L, 2022) (Bartell SM, 2021). Hence, the sensitive detection of these substances is a major concern worldwide. The most widely used analytical technique is liquid chromatography-tandem mass spectrometry combined with solid phase extraction. It was approved by the Environmental Protection Agency of the USA for 29 PFAS (Rosenblum L., 2019). However, it is unsuited for on-site analyses and requires highly-skilled users. Alternative analytical approaches are currently under investigation.

Objectives

Here, we propose to use an electrochemical approach to detect PFAS with ionizable properties (PFOA: perfluorooctanoic acid, PFOS: perfluorooctane sulfonic acid for example). Direct oxidation or reduction of such substances is not feasible due to their chemical stability, so indirect detection is required. The strategy here is to investigate a seldomly used approach based on electrochemistry at interfaces between two immiscible electrolyte solutions (ITIES). In this approach, the electrical polarization between two immiscible solutions drives the transfer of non-redox species from one phase to another, resulting in an electrical signal proportional to the concentration of the non-redox species. Few publications have demonstrated the capacity of this approach to detect PFAS at ng/L limit of detection (Lamichhane HB, 2023) (Islan GJ, 2022) (Viada BN, 2020), which is compatible with PFAS concentration found in drinking water. The novelty of this project is to combine this electrochemical detection with microfluidic technology. Microfluidic is a powerful approach to develop analytical platforms that can be both sensitive due to miniaturization and automated thanks to integration. We believe that this combination will circumvent some of the limitations of the current approaches.

For a description of the host laboratory:

https://inl.cnrs.fr/presentation-du-laboratoire/

https://inl.cnrs.fr/en/about-inl/

We are seeking highly motivated students with an interest in environment and electroanalytical methods and their implementation in microfluidic systems.

Candidate should be currently following a master program in either: Analytical chemistry, chemical engineering, Micro-technologies, or Physical-Chemistry