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S O
O
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
O
PFOA
PFOS
O
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
O H
Figure 2. Examples of PFAA target compounds – PFOA and PFOS
Organic phase
Dilution with
deionized water
Extraction with TBAS
and MTBE
Evaporation to
dryness
Methanol/
Ammonium acetate
Filtration
Homogenization
pH adjustment
5 g Sample
LC-MS ESI
Surrogate standard
addition
Figure 3. Sample preparation process