Thermo Fisher Scientific Inc. has developed a new method for sensitive and reproducible quantitation of low levels of perfluorinated compounds (PFCs) in human breast milk. Using selected reaction monitoring (SRM) and highly selective reaction monitoring (H-SRM) on an integrated ultra high performance liquid chromatography mass spectrometry (UHPLC/MS) platform enables reliable and robust detection of PFCs at ppt concentrations in human breast milk.
The new method is detailed in an application note, entitled "Sensitive and Accurate Quantitation of Perfluorinated Compounds in Human Breast Milk using Selected Reaction Monitoring Assays by LC/MS/MS," which is available to download via http://www.thermoscientific.com/pfc.
Liquid chromatography tandem mass spectrometry (LC/MS/MS) has long been the method of choice for the analysis of PFCs, but quantitation accuracy is often jeopardized due to background PFC contamination and matrix interferences. UHPLC/MS is an alternative for monitoring low levels of PFCs in a range of human matrices, delivering precise and reproducible measurements.
Many PFCs are detectable in human serum and breast milk and have been found in the blood of newborns possibly through lactational transfer from mothers. By coupling the Thermo Scientific Accela UHPLC and the PAL autosampler to the Thermo Scientific TSQ Vantage triple-stage quadrupole MS the system was able to provide rapid, accurate and robust analysis and quantitation of six PFCs in human breast milk using SRM and H-SRM.
Elimination of PFC contamination was achieved using a PFC-free Accela pump with a pre-cleaned PFC-free degasser while also replacing Teflon tubing with PEEK tubing. The sensitivity and selectivity afforded by SRM on the TSQ Vantage system obviated the need for any further modifications of the LC configuration, a distinct advantage over other commercial platforms that require the use of in-line contaminant traps or column-switching methods for PFC analysis.
Using the integrated UHPLC/MS platform, separation of the six PFC analytes in a spiked human breast milk matrix was achieved within nine minutes, Thermo Scientific informed. As the majority of interferences from matrices elute early at void volume, elution of the first compound at 3.64 minutes ensured a robust quantitation method. Excellent linearity in detector response was observed while H-SRM eliminated matrix interferences without compromising sensitivity, the company has claimed.
The Accela system, combined with 1.9 µm particle columns, enables efficient chromatographic separations over an expansive range of flow rates and pressures. Delivering up to a tenfold improvement in signal-to-noise ratio compared to existing triple-quadrupole MS systems, the TSQ Vantage facilitates highly sensitive quantitation in matrix-rich samples and enhances analytical precision.