Detection of perfluorooctane sulfonate by ion-transfer stripping voltammetry at an array of microinterfaces between two immiscible electrolyte solutions

Abstract

<p>Per- and polyfluoroalkyl substances (PFAS) are a category of persistent environmental contaminants that have been linked to health issues in humans. In this work, we investigate the detection of perfluorooctanesulfonate...</p>

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

“…On the other hand, the broad peak on the reverse scan (scanning from lower to higher potentials) indicates linear diffusion control of PFOS transfer from the inner organic phase to the aqueous phase . These findings are in agreement with previous accounts of ion-transfer voltammetry of PFAS at the 1-octanol/water interface, at the water/plasticized polymer membrane interface, and of PFOS at a water/DCE μITIES array …”

“…46 These findings are in agreement with previous accounts of ion-transfer voltammetry of PFAS at the 1-octanol/water interface, 40 at the water/plasticized polymer membrane interface, 41 and of PFOS at a water/ DCE μITIES array. 42 The half-wave potential E 1/2 provides a qualitative property for an analyte within a particular supporting electrolyte solution. Figure 1a (inset) shows that in the forward scan for background-subtracted 6 μM PFOS, the ion transfer starts at 0.44 V and reaches the plateau at 0.24 V, and the E 1/2 is 0.34 V (see Figure S2 for estimation of E 1/2 values, being the potential at which the current is one half of the limiting current).…”

“…Amemiya’s group also reported on PFAS detection by ion transfer stripping voltammetry at the ITIES formed between an aqueous electrolyte and a plasticized polymeric thin film on an electrode, achieving a LOD of 50 pM for PFOS, following a 30 min preconcentration period. Recently, Viada et al reported on PFOS detection by ion transfer differential pulse stripping voltammetry (DPSV) at an array of μITIES. The LOD for PFOS in an aqueous electrolyte was 30 pM (i.e., 0.015 μg L –1 ) following a 5 min preconcentration period.…”

“…The LOD for PFOS in an aqueous electrolyte was 30 pM (i.e., 0.015 μg L −1 ) following a 5 min preconcentration period. Viada et al 42 also studied sample matrix effects, finding changes in sensitivity and LOD relative to those in pure aqueous electrolyte solutions.…”

Ion Transfer Voltammetry with an Electrochemical Pen

“…This is well known in electrochemistry/electroanalysis. 31 If ions are naturally present in a sample, such as seawater 32 or brackish water, electrochemical measurements can often be made without the addition of electrolyte and even in purified solvents where sufficient electrolyte impurities are present to support electrochemical measurements. 33 In contrast, in our experimental arrangement, the new platform (paper) might provide sufficient background ions to minimize migration and resistance adequately, and hence, no additional salt needs to be added; in this way, liquid samples could be analyzed without first modifying them by the addition of electrolyte.…”