Page 58 - Application Notebook - PFAS Analysis

No. SSI-LCMS-119

Table 1: Chromatography and mass spectrometer conditions.

Parameter Value
LCMS Shimadzu LCMS-8050
Restek Raptor C18 2.1 mm ID. x 150 mm L., 2.7 μm)
Analytical Column
Part No 9304A62
Restek PFAS Delay Column (2.1 mm ID. x 50 mm L)
Solvent Delay Column
Part No. 27854
Column Oven Temperature 40 º C
Injection Volume 30 µL
A: 20 mmol Ammonium Acetate in 5 % (v/v) Acetonitrile in reagent water
Mobile Phase
B: 10 mmol Ammonium Acetate in 95 % (v/v) Acetonitrile in reagent water
Gradient Flow rate 0.3 mL/ Min
Gradient Time (minutes) % B
0 0
1 20
6 50
14 100
17 100
18 0
21 0
Run time 21 minutes
Nebulizing gas flow 5 L/min
Heating gas flow 15 L /Min
Interface temperature 300 °C
Desolvation Line temperature 100 °C
Heat Block temperature 200 °C
Drying gas flow 5 L /min
Acquisition cycle time 21 min
Total MRMs 66

■ Results and Discussion
It is known that PFAS can be present in reagents, To monitor the lack of contamination two blanks
glassware, pipettes, tubing, degassers and other were injected at the beginning of each batch: system
parts from the LC-MS/MS instruments. PFAS null injection (air injection) and reagent blank (0.1%
contamination coming from the LC system is acetic acid in high purity water:methanol (50:50)).
eliminated using a delay column placed between the Figure 1 shows the schematic of the delay column
reagents and the sample valve. This separates PFAS set up, and Figure 2 shows the importance of having
in the sample from the PFAS in the LC system. All a delay column and its impact on data quality.
supplies used to conduct the study were free from
PFAS contamination.

Figure 1: Schematic of Delay Column System to minimize background PFAS.