COMPLETING THE PROCEDURE FOR DETERMINING THE CONTENT OF PERFLUOROOCTANESULFONIC ACID (PFOS) IN WASTEWATER USING LIQUID CHROMATOGRAPHY-MASS SPECTROMETRY (LC-MS)

Perfluorooctanesulfonic acid (PFOS) and its salts are persistent organic pollutants (POPs), enumerated in Annex B of the Stockholm Convention, which imposed restrictions on their production and utilization. This work described the analytic procedure of PFOS in wastewater using the techniques of liquid-liquid extraction in combination with a system of liquid chromatography coupled with a triple quadrupole mass spectrometer (LC-MS/MS). The solvent for liquid-liquid extraction and the operation conditions (collision energy, fragment pick, mobile phase) were completed to obtain an effective analytic procedure with a limit of detection (LoD) of 0.5 ng/L, a limit of quantification (LoQ) of 2.0 ng/L, a relative standard deviation (RSD) of <10%, and good reproducibility for three-time liquid-liquid extraction (the efficiency of ≥80%). The results of PFOS analysis in two wastewater samples of the international interlaboratory comparison program had a Z-score value of < ±1. The optimized procedure was also applied to assess five different practical samples.