A simple and rapid extraction method for sensitive determination of perfluoroalkyl substances in blood serum suitable for exposure evaluation

In this work, we propose a microextraction method based on a new supramolecular solvent (SUPRAS) made up of reverse aggregates of hexanoic acid, combined with liquid chromatography/triple quadrupole mass spectrometry (LC/QQQ MS-MS) for the determination of the perfluoroalkyl substances (PFASs) in blood serum. A SUPRAS is a nano-structured liquid made up of surfactant aggregates synthesized through a self-assembly process. The method involved the acidification of 765 mu L of blood serum (600 mu mol of hydrochloric acid per mL of serum) followed by the addition of hexanoic acid (97 mu L) and tetrahydrofuran (THF) (600 mu L), conditions under which the supramolecular solvent (similar to 360 mu L) formed in situ after vortex-shaking and centrifugation. Parameters affecting extraction efficiency and concentration factors were studied. The overall sample treatment took only 20 min and several samples (20-30) can be simultaneously analyzed using conventional lab equipments, making additional investments unnecessary. Recoveries for the internal standards in samples ranged from 75 to 89% with relative standard deviations between 1 and 15%. Calibration was based on the use of internal standards. The method was very sensitive with detection limits ranging from 2 to 20 pg mL(-1) for PFASs. The approach developed was successfully applied to the determination of PFASs in different blood serum samples. The concentration of PFASs found in samples of animal origin ranged between 17 and 197.3 pg mL(-1) and between 84 and 5168 pg mL(-1) in samples of human origin. Both the analytical and operational features of this method make it suitable for the evaluation of exposure to PFASs. (C) 2012 Elsevier B.V. All rights reserved.