Using the Markes’ TD100-xr™ high through-put automated thermal desorption (TD) instrument to preconcentrate the sample and maximise sensitivity, coupled to a gas chromatograph (GC) and a triple quadrupole mass spectrometer (MS/MS), enables measurement of PFAS in indoor air
Poly And Per Fluoroalkyl Substances (PFAS) are everywhere. Whilst there has been a lot of focus internationally on PFAS in water, researchers and governments globally are turning their attention to volatile gas phase species in air.
Gaseous PFAS have many sources including PFAS production facilities, aqueous film forming foams (AFFF), soil gas, materials and remediation of PFAS impacted sites/materials. PFAS in the air can spread easily, transform into more toxic species1 and impact other matrices, such as water and soil, through deposition. Understanding and monitoring PFAS in air is an important part of controlling the spread of PFAS and reducing exposure to humans.
Thermal desorption coupled to gas chromatography and mass spectrometry (TD-GC-MS) is commonly applied to monitoring of hazardous organic compounds in ambient air. The technique is being utilised successfully by environmental agencies and researchers globally to monitor gaseous PFAS2.
In this study we will show how TD-GC-MS can offer a robust approach to target and non-target screening of PFAS in a variety of samples.
Gas phase PFAS method
PFAS are present in the air and dust in indoor environments4, the toxicology and bioaccumulation of these compounds means that understanding their presence and concentration in indoor air is important.
Using the Markes’ TD100-xr™ high through-put automated thermal desorption (TD) instrument to preconcentrate the sample and maximise sensitivity, coupled to a gas chromatograph (GC) and a triple quadrupole mass spectrometer (MS/MS), enables measurement of PFAS in indoor air at a detection limit as low as 1 pg for Me-FOSA.
Two runs enable the analysis of the ultra-volatile CF4 and the other VFCs/OTM-50 compounds without the need to change the hardware or consumables. It should be noted that 100% RH has been assessed in other studies of similar compounds without issue thanks to the Kori-xr module selectively removing water. The highlights for VFC analysis include the excellent:
Method detection limits of 30ppt for CF4 and <14ppt all other VFCs
Reproducibility of <2.04% RSD 5ppb
Linearity of >0.9976 R2.
For gas phase PFAS, the TD-GC-MS/MS method developed for the 19 compounds targeted in this study delivered an average detection limit of 16 pg. The technique is stable and sensitive enough to analyse the more volatile neutral PFAS species and volatile PFCAs in a single run. The highlights for gas phase PFAS analysis include impressive:
Method detection limits of <65pg (as low as 1 pg for Me-FOSA)
Reproducibility of <5.76% RSD
Linearity of >0.9936 R2.
