Zone electrophoresis separation of perfluorocarboxylic acids on a chip with conductivity detection

Abstract

Perfluorinated carboxylic acids (PFCAs), amphiphiles of anthropogenic origin, are spread worldwide throughout the environment. This work deals with their zone electrophoresis (ZE) separation on a chip with coupled columns and integrated conductivity detection. Analogies with the electrophoretic behavior of PFCAs and fatty acids were employed in a search for electrolyte conditions suitable for their separation. ZE separations in the water-ethanol electrolyte systems, based on differences in the ionic mobilities of the anions of PFCAs, provided favorable resolution and detection conditions of the homologues containing up to 10 carbon atoms in the alkyl chain. Concentration limits of detection of 0.3-6.5 micromol/L were attained for PFCAs (loaded by a 900 nL volume sample injection channel of the chip) under these separation conditions. The material of which the chip was made [poly(methylmethacrylate)] restricted its use in investigations of the separations of higher PFCA homologues as it was damaged by ethanolic and/or methanolic background electrolyte solutions required in experiments with these amphiphilic compounds.

New Analytical Methods Developed for Determination of Perfluorinated Surfactants in Waters and Wastes

“…We have also developed a CE method based on the use of a capillary electrophoretic microfluidic chip with conductivity detection. 27 This first attempt resulted with a separation of PFCAs from C6 to C10 carbon atoms and detection limit at the level of 0.3 to 6.7 μmol L -1 . The aim of other studies was to optimize also a capillary electrophoretic method for determination of PFCAs with the indirect spectrophotometric detection.…”

Recent advances in CE and CEC of pollutants

“…There has been much active research into the separation of various organic acids [43,45,52,66,74,75,81,86,[96][97][98][99][100][101][102]. Novel procedures for determining low-molecular-weight aliphatic acids [43,52,86,99,101,102], phenolic acids [45,100], and other aromatic acids [81,74] have been developed.…”

“…Novel procedures for determining low-molecular-weight aliphatic acids [43,52,86,99,101,102], phenolic acids [45,100], and other aromatic acids [81,74] have been developed. Methods for improving the reliability of CE measurements were also discussed [96,99].…”

“…Most of the research has been focused on amperometric [34][35][36][37][38][39][40][41][42] and conductometric detection [43][44][45], especially when integrated with microchip-based CE [3, 4, 19, 20, 35, 36, 38-40, 42, 43, 46]. For example, amperometric detection, which is suitable for electroactive species, was successfully employed to analyze six chlorinated phenols (2-chlorophenol, 3-chlorophenol, 4-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol, pentachlorophenol) in river water using a homemade CE system with a diamond microelectrode [34].…”

Monitoring of enzymatic reactions using conventional and on‐chip capillary electrophoresis with contactless conductivity detection

“…The determination of small carboxylates is readily possible in CE with conductivity detection, see for example ref. [27][28][29][30], so that the indirect determination of the ester via determination of acetate as the reaction product was expected to be feasible.…”