UHPLC-MS/MS Determination of Perfluorooctane Sulfonic Acid and Perfluorooctanoic Acid in Leather

The samples were extracted with methanol, and PFOS and PFOA in sample solution were separated and enriched by solid phase extraction (SPE) on anion-exchange column. The SPE column was eluted with a mixture of ammonia (aq.) and methanol (1+99), and the eluate obtained was evaporated to dryness by N2-blowing at 45 ℃ and taken up with 5 mL of a mixture of acetonitrile (A) and 5 mmol·L-1 NH4OAc solution (B) mixed in the ratio of 42 to 58. An aliquot of 10 μL was used for UHPLC-MS/MS determination, in which the C18 (100 mm×2.1 mm, 5 μm) column was used as chromatographic column, and mixtures of A and B in different ratio were used as mobile phase in gradient elution; negative electrospray ionization as well as multiple reaction monitoring mode were used in the detection. Linearity ranges of PFOS and PFOA were found to be in the same range within 40.0 μg·L-1 with their detection limits (3S/N)of 1 μg·L-1. Test for recovery and precision were made by standard addition method at 3 different concentration levels, values of recovery found were in the range of 90.0%-99.4% for PFOS and 91.6%-104.0% for PFOA, and values of RSD′s (n=6) were less than 13%.