Separation of perfluorocarboxylic acids using capillary electrophoresis with UV detection

Abstract

A capillary electrophoretic method with UV detection for separation and quantitation of perfluorocarboxylic acids (PFCAs) from C6-PFCA to C12-PFCA has been developed. The optimization of measurement conditions included the choice of the most appropriate type and concentration of buffer in the background electrolyte (BGE), as well as the type and the content of an organic modifier. The optimal separation of investigated PFCAs was achieved with 50 mM phosphate buffer and 40% isopropanol in the BGE using direct UV detection. The optimum wavelength for direct UV detection was optimized at 190 nm. For indirect detection, several chromophores were studied. Five mM 3,5-Dinitrobenzoic acid (3,5-DNBA) in 20 mM phosphate buffer BGE and indirect UV detection at 280 nm gave the optimal detection and separation performance for the investigated PFCAs. The possibility of on-line preconcentration of solutes by stacking has been examined for indirect detection. The detection limits (LODs) determined for direct UV detection ranged from 2 microg/mL for C6-PFCA to 33 microg/mL for C12-PFCA. The LODs obtained for indirect UV detection were comparable to those obtained for direct UV detection.

Recent developments in methods for analysis of perfluorinated persistent pollutants

“…In case of determination of PFCAs an additional limiting factor is a weak absorption of UV/Vis radiation. In optimized conditions of pH and background electrolyte (BGE), a satisfactory separation was reported for C6 to C12 PFCAs, but for direct UV detection at 190 nm the limits of detection were in the range 2–33 mg · L −1 , only [73]. …”

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

“…In our studies we have developed a CE methods for determination of PFCAs with 6 to 12 carbon atoms in alkyl chain with a direct UV detection. 26 Because of the weak absorption of light by the target PFCA analytes, the detection limits without any additional preconcentration step were from 2 to 33 mg L -1 . We have also developed a CE method based on the use of a capillary electrophoretic microfluidic chip with conductivity detection.…”

Recent advances in capillary electrophoresis and capillary electrochromatography of pollutants

“…The use of CE method with UV detection for separation and quantitation of perfluorocarboxylic acids (C 6 -PFCA to C 12 -PFCA) was recently reported [176]. The optimal separation of the studied PFCAs was achieved with 50 mM phosphate buffer at pH 9.5 containing 40% isopropanol, and using direct UV detection at 190 nm.…”