Page 57 - Application Notebook - PFAS Analysis

No. SSI-LCMS-119

Liquid Chromatography Mass Spectrometry

Are there PFAS in my water?

A detailed look into bottled
water
No. LCMS-119

■ Introduction
The presence of Per- and Polyfluorinated Alkyl Chromatography was adjusted to obtain maximum
Substances (PFAS) in drinking water is being resolution between peaks in the shortest time
thoroughly studied due to the persistence of these possible with minimum co-elution of isomers. The
compounds in the environment and their potential total run time of 21 minutes includes a final wash
health effects. However, there is limited knowledge out with concentrated acetonitrile to flush the
about the occurrence of these chemicals in bottled column, remove background residuals contaminants
water, despite the increasing concerns about PFAS in and restore column performance before starting the
the food supply. This work presents results from a next run. The method could easily be modified to
fast and simple direct injection method similar to EPA include isotopic dilution or internal calibration if
method 8237, using the Shimadzu LCMS-8050 to needed for quantifying the concentrations.
analyze seven commercially available samples of
bottled water for 24 PFAS. The results demonstrate Calibration Standards
that the instrument’s performance exceeds the Standards available from Wellington Laboratories
requirements in FDA draft method C-010.01 for were used for these studies (Catalog no. PFAC-
other matrices, including milk (which is the most 24PAR and MPFAC-24ES). These standards were
similar to water), as well as the limits established by then diluted to working standards using 95:5
the EPA for drinking water. acetonitrile:water as the diluent. The working
standards were used to create a calibration curve
While the origin of the water itself maybe the source ranging from 5-200 ppt with the injection solvent
of PFAS in bottled water, we also wanted to consisting of 50:50 water:methanol with 0.1%
investigate the importance of the type of materials. acetic acid in order to match the injection solvent for
Migration of PFAS from Food Contact Materials the extracted samples. Filtration was not performed
(FCM) is known to occur in all kinds of food on the calibration standards.
containers. In this study, we procured bottled water
in several different bottle materials, as well as two Sample Preparation
types of water source. These included spring and Seven types of bottled water as sample matrices
purified water, and bottles made from 5 different were tested using reagent water as the blank. Each
kinds of container materials: plastic (virgin and sample was diluted 50:50 with MeOH and 0.1%
recycled), glass, metal, and cardboard. Preliminary acetic acid, spiked with isotopically labeled
results indicate that observed PFAS levels seem to surrogates and vortexed for 2 min. The samples were
depend on both the bottle material and the water then filtered through 0.2 μm syringe filters and
source. analyzed by LC/MS/MS.

■ Methodology All compound parameters, including precursor ion,
We analyzed 24 target PFAS compounds and 19 product ion, and collision energies, were optimized.
surrogates in various types of water. The analysis of There are at least two multiple reaction monitoring
PFAS was performed using a Shimadzu Nexera X2 (MRM) transitions for most of the analytes.
SIL-30AC autosampler and a LCMS-8050 triple
quadrupole mass spectrometer. An injection volume
of 30 µL was used in this study. A detailed
description of the LC/MS/MS parameters is included
in Table 1.