Luminescence lifetime-based sensing solid interfaces for the determination of Perfluoroalkyl substances (PFAS)

Zhang, Kun ORCID: 0000-0002-2701-6075 (2024). Luminescence lifetime-based sensing solid interfaces for the determination of Perfluoroalkyl substances (PFAS). University of Birmingham. Ph.D.

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Abstract

The presence of per- and polyfluoroalkyl substances (PFAS) in humans arises from their large-scale use in multiple industrial and consumer applications. Such uses have led to human exposure via a range of pathways of which is concerning given evidence of the adverse health impacts of PFAS. However, conventional LC-MS methods for measuring PFAS are economically and logistically unsuited to monitoring compliance with this limit, and less expensive, faster and user-friendly methods for the quantification of PFAS are urgently required. Luminescence lifetime is an attractive analytical method for detection due to its high sensitivity and stability, and there is great interest for the design of detection platforms for monitoring of PFAS concentrations in different environmental contents. Herein, three novel luminescence lifetime-based sensing platforms were developed for the accurate and rapid detection of PFAS (e.g. PFBA, PFOA, PFNA, PFDA, etc) in different environmental contexts.
Chapter III describes the fabrication and function of a novel and facile luminescence sensor for PFOA detection based on iridium modified gold surfaces. These surfaces were modified with lipophilic iridium complexes bearing alkyl chains, namely, IrC6 and IrC12, and Zonyl-FSA surfactant. Upon addition of PFOA, the modified surfaces IrC6-FSA@Au and IrC12-FSA@Au show the largest change in the red luminescence signal with changes of the luminescence lifetime that allow monitoring of PFOA concentrations in aqueous solutions. The platform was tested for measurement of PFOA in aqueous samples spiked with known concentrations of PFOA, and demonstrated capacity to determine PFOA at concentrations >100 µg/L (240 nM).
Chapter IV describes a functionalised gold surface based on a SAcbisDBM ligand and Europium(III) to rapidly and accurately measure the concentrations of C4 to C10 PFCA in waste fabrics. The surface was modified with SAcbisDBM ligand, subsequently coordinated with Europium(III), namely Eu-SAcbisDBM@Au surface, displaying high affinity towards perfluoroalkyl carboxylic acids (PFCA) and is reusable. Under optimal conditions, the surfaces can detect >80 nM PFCA. The potential utility of the sensor is demonstrated by the good agreement between concentrations recorded by the sensor and LC-MS measurements of C4-C10 PFCA in 34 leather, leatherette, and textile samples.
Chapter V investigates the use of near infrared-emitting lanthanides, such as Neodymium(III) and Ytterbium(III) coordinated with the SAcbisDBM ligand, in solution (Nd/Yb-SAcbisDBM) or on plasmonic gold (pAu) surface (Nd-pAu and Yb-pAu), to detect PFCA such as PFOA, PFNA, and PFDA in water. Upon the addition of PFCA (e.g. PFDA), both Nd-SAcbisDBM and Yb-SAcbisDBM show a significant increase in luminescence, displaying a detection range as low as 2 µM and 10 µM, respectively. The luminescence properties of Nd-pAu and Yb-pAu also present a positive correlation with the concentration of PFCA. The sensing systems exhibit enormous potential for the detection of PFAS, offering valuable insights for environmental monitoring.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):