Perfluorooctanesulfonic acid (PFOS) and Perfluorooctanoic acid (PFOA) rarely decompose in the natural environment and thus their persistence in the environment and accumulations in living organisms are problems to be considered. They are subjects of the Stockholm Convention on Persistent Organic Pollutants.
In this application, RSpak JJ-50 2D, a multimode (reversed-phase + anion exchange) column was used to analyze PFOS and PFOA. Eluents with different composition ratios of acetonitrile and ammonium hydrogen carbonate aqueous solution were tested under isocratic conditions. Plotted retention times (tR) with respect to acetonitrile ratio showed a U-shape trend. At 90 % and 30 % acetonitrile conditions, PFOS and PFOA were not detected in the user setting, respectively. Most likely, they were retained longer than 20 minutes. The higher signal-to-noise ratio (S/N) was achieved with the higher acetonitrile eluent. This is because the presence of larger acetonitrile content promoted the desolvation at the ion source.
Sample : 100 ng/mL each, 1 μL
PFOS, Perfluorooctanesulfonic acid
PFOA, Perfluorooctanoic acid
Column : Shodex RSpak JJ-50 2D (2.0 mm I.D. x 150 mm) Eluent : 50 mM NH4HCO3 aq./CH3CN=70/30, 60/40, 50/50, 40/60, 30/70, 20/80, 10/90 Flow rate : 0.2 mL/min Detector : ESI-MS (SIM Negative) Column temp. : 40 °C