Thermo Fisher Scientific has developed a method for sensitive, accurate and reproducible quantitation of low levels of perfluorinated compounds 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 perfluorinated compounds (PFCs) at ppt concentrations in human breast milk.
The method is described 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'.
PFCs have been widely used in diverse industrial applications as well as consumer products for more than 50 years.
Many of these synthetic compounds become environmental pollutants as they are resistant to degradation and laboratory studies have linked some PFCs to developmental, reproductive and systemic toxicity.
In response, efforts have been made to regulate PFCs and identify a dependable method for trace-level analysis of these hazardous compounds in order to determine exposure pathways and health outcomes.
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 jeopardised 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 sensitive, selective, 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 degreaser while also replacing Teflon tubing with Peek tubing.
The sensitivity and selectivity afforded by SRM on the TSQ Vantage system obviated the need for further modifications of the LC configuration, an advantage over 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 9mins.
As the majority of interferences from matrices elute early at void volume, elution of the first compound at 3.64mins ensured a robust quantitation method.
Excellent linearity in detector response was observed while H-SRM eliminated matrix interferences without compromising sensitivity.
The Accela system, combined with 1.9um particle columns and a high-pressure quaternary pump, enables fast and efficient chromatographic separations over an expansive range of flow rates and pressures.
Delivering up to a tenfold improvement in signal-to-noise ratio compared with existing triple-quadrupole MS systems, the TSQ Vantage facilitates highly sensitive quantitation in matrix-rich samples and enhances analytical precision.
The instrument is capable of high-resolution selection of precursor ions, enabling H-SRM for greater analytical selectivity and accuracy.