Page 53 - Application Notebook - PFAS Analysis

No. SSI-HPLC-037

Table 2: LC-MS/MS method conditions used in Shimadzu LCMS-8050

Item Value
Column Shim-pack GIST C18 2.7 um 100 x 2.1 mm
Delay column XR-ODSII 3 x 75 mm
Mobile phase A: 10 mM ammonium acetate in H2O; B: MeOH
Flow rate 0.5 mL/min
0 min: 20% B
9 min: 90% B
Gradient 11 min: 90% B
11.5 min: 20% B
15 min: 20% B
Oven temperature 35 C
o
Injection volume 1 µL
Ionization mode ESI (-)

Figure 2: LC-MS/MS chromatogram of target PFAS in a commercial standard diluted in MeOH (50 pg each on column)

■ Results and Discussion
Recovery, Linearity, Reproducibility Linearity results are shown in Table 4 along with the
A set of experiments to identify the combination of determined limit of quantitation for each compound;
CO2’s modifier and additives that maximized the r for all compounds was >0.9995 except for N-
2
extraction efficiency of 18 PFAS was first conducted MeFOSAA (r : 0.9994). Linearity results show
2
in this work. While 100% CO2 can be effective in accurate determinations for PFAS compounds can be
extracting nonpolar compounds, the addition of a obtained regardless of concentration levels.
cosolvent is often required in SFE to extract more
polar compounds. Optimum extraction conditions Reproducibility results for supercritical fluid
were found to be 20% methanol without the need extractions were determined at three PFAS
for additives. The 18 targets from this study showed concentration levels: 2 ng/g, 20 ng/g and 100 ng/g.
recoveries over 95% with these conditions, as shown Extractions were performed in triplicated samples.
in Table 3. Table 5 summarizes the variability of the extraction
at each of the concentrations evaluated. %RSDs at
Linearity of a matrix matched calibration curve, to 20 and 100 ng/g were less than 12% for all
minimize the impact from coextracted matrix compounds evaluated. At 2 ng/g, %RSD was less
components, was evaluated. Concentrations from than 25%, except for PFTriA (27%) and N-MeFOSAA
0.5 to 100 ng/g were spiked to a freeze-dried farm- (45%). These results demonstrate the reproducibility
raised trout fish tissue sample found to be free from of SFE as a sample preparation technique.
PFAS contamination.