Mass Spectrometry Analysis of PFAAs and OPEs

The samples were analyzed for PFAAs using
negative electrospray ionization (ESI) tandem mass spectrometry (Table S1). Analytes were detected using an API
4000 Q Trap (Applied Biosystems, Carlsbad, CA) after chromatographic
separation with an Agilent 1100 LC (injection volume = 40 μL,
flow rate = 300 μL/min). Chromatography was performed using
an ACE C18 column (50 mm × 2.1 mm, 3 μm particle size,
Advanced Chromatography Technologies Ltd., Aberdeen, U.K.), preceded
by a C18 guard column (4.0 × 2.0 mm, Phenomenex, Torrance, CA),
and the column oven was set to 30 °C. Samples were quantified
with a six-point calibration curve using the isotopic dilution method.
Samples were analyzed for OPEs using positive ESI (Table S1). Analytes were detected using an ultrahigh
performance LC/MS/MS) consisting of Water XEVO TQS triple quadrupole
MS coupled to a Water Acquity LC. Separation was performed using an
Acquity UPLC BEH C₁₈ column (Waters, 1.7 μm, 2.1
× 100 mm²) in a 60 °C thermostated compartment
using 0.1% formic acid in water (A) and 0.1% formic acid in methanol
(B) gradient.