The Implementation of a Screening Workflow for Ion Mobility Quadrupole Time-of-Flight Mass Spectrometric Analysis of PFOS Isomers

Oral Presentation

Prepared by K. Rosnack1, M. McCullagh2, L. Dillon2, I. Jogsten Ericson3, B. van Bavel3, L. Mullin1, J. Burgess1
1 - Waters Corporation, 34 Maple Street, Milford, MA, 01757, United States
2 - Waters Corporation, Stamford Ave, Wilmslow, SK94AX, United Kingdom
3 - MTM Research Centre, Orebro University, Orebro, SE-701 82, Sweden

Contact Information: [email protected]; 508-482-4639


Perfluorinated compounds (PFCs) are a class of man-made compounds that are frequently detected globally in biological and environmental samples. Perfluorooctane sulfonate (PFOS) is frequently detected in biological and environmental samples. MRM transition based LC-MS/MS analyses have been used previously to investigate PFOS in marine animals and human serum. Benskin et al. reported a common matrix interferent (taurodeoxycholate [TDCA]) that can complicate PFOS quantitation because it undergoes the same transition (499 m/z → 80 m/z) and tends to co-elute with PFOS, giving a positive bias. The use of high definition mass spectrometry (HDMS) is explored as an important tool for unequivocal identification of PFOS isomers in environmental samples. The assay is based on the analysis of environmental sample extracts, mink liver and fish. Negative ion electrospray with ion mobility MSE data acquisition was performed using a Synapt G2-S HDMS mass spectrometer. The results obtained to determine the presence of PFOS in mink, show the benefits of using HDMS. It is possible to separate co-eluting analytes and increase the peak capacity using ion mobility. The PFOS isomers were resolved from the interfering components as they have vastly different mobility drift times. (Ion mobility information provides another component of analytical separation, and is of particular utility in complex matrices.) All of the mass spectral information is retained, precursor and fragmentation information is acquired simultaneously and drift times enabling further characteristic profiling. With this information, it has been possible to create a characteristic assignment profile of PFOS isomers that co-elute with the cholic acid interferences. Using a novel software platform, the target retention times were profiled to automatically generate the precursor and fragmentation spectra as well as the drift times for the identified PFOS isomers.