Voltammetric Selectivity in Detection of Ionized Perfluoroalkyl Substances at Micro-Interfaces between Immiscible Electrolyte Solutions

Abstract

Widespread contamination by per-and polyfluoroalkyl substances (PFAS) and concern about their health impacts require the availability of rapid sensing approaches. In this research, four PFAS, perfluorooctanoic acid (PFOA), perfluorobutanesulfonic acid (PFBS), perfluorohexanesulfonic acid (PFHxS), and perfluorooctanesulfonic acid (PFOS), were studied at micropipette-based interfaces between two immiscible electrolyte solutions (μITIES) to assess the potentiality for their detection by ion transfer voltammetry. All four PFAS substances were detected by ion transfer voltammetry at the μITIES, with halfwave transfer potentials (E 1/2 vs Ag/AgCl) for PFOS, PFHxS, PFBS, and PFOA of 0.34, 0.32, 0.25, and 0.23 V, respectively. The selectivity of the μITIES for detection of PFAS mixtures was investigated. Among the six combinations of the four compounds, most combinations were detectable, except PFOA + PFBS and PFHxS + PFOS, because of unresolved ion transfer voltammograms. These findings provide a basis for the design of new PFAS sensing strategies based on ion transfer voltammetry.

Ion-transfer electroanalytical detection of perfluorooctanoic acid at a liquid–liquid micro-interface array

“…Asymmetric CVs were obtained in all cases, with steady-state voltammograms on the forward sweep (due to radial diffusion to the pores holding the μITIES), scanning from positive towards negative potentials, while the reverse-direction scans are peak shaped (due to linear diffusion within the pores), in agreement with previous studies. 67,68 CV also indicated no adsorption, emulsification, or instability of the interface. 67 In all cases, the reverse peak currents increased linearly with the PFOA concentration in the studied ranges (Fig.…”

“…67 A recent study assessed the prospects for selectivity in the detection of PFAS mixtures by ion transfer electrochemistry at a micropipette-based μITIES. 68 Whilst PFOS can be detected sensitively at a μITIES array, 67 no studies were reported on PFOA detection at low concentrations.…”

An Overview on Recent Advances in Biomimetic Sensors for the Detection of Perfluoroalkyl Substances

“…Surface imprinting of low-molecular-weight compounds can be achieved by depositing and imprinting a polymer layer directly on an electrode surface via electropolymerization, which is a particularly useful method in combination with electrochemical transducers [ 113 , 114 ]. By cycling the potential in a predetermined range with a given sweep rate, the electroactive monomer (such as aniline, o-phenylenediamine, and pyrrole) will be electropolymerized and the substrates will be coated by a very thin layer of polymer [ 81 , 92 , 115 ].…”

Modulating the ion-transfer electrochemistry of perfluorooctanoate with serum albumin and β-cyclodextrin

“…47 Despite some disadvantages of the ITIES, such as instability and high capacitance, improvements have progressed by miniaturisation 48,49 to microscale and by mechanical support with porous membranes or gelled organic phases. [50][51][52][53][54] As a result, PFAS electrochemical detection and sensing has been investigated at the ITIES [55][56][57][58] including the microITIES (µITIES). 55,59 We have previously reported the sensitive detection of PFOA with this approach and identified the impact of matrix components on the electrochemical detection of PFOA.…”