Rapid Quantification of Perfluorinated Compounds in Drinking and Surface Water Using LC-MS/MS

Poster Presentation

Prepared by W. Lipps1, J. Post2
1 - Shimadzu Scientific Instruments, 7102 Riverwood Dr., Columbia, MD, 21046, United States
2 - Shimadzu Scientific Instruments, 7100 Riverwood Dr., Columbia, MD, 21046,


Contact Information: wclipps@shimadzu.com; 410-910-0802


ABSTRACT

Perfluorinated compounds (PFCs) are synthetic molecules with carbon chains to which fluorine is bound by high strength carbon-fluorine covalent bonds. These molecules, now classified as persistent organic pollutants, are highly stable and resistant to biological degradation; therefore, they persist in the environment, bioaccumulate, and due to their ready transport by water, are found even in remote regions of Earth. Analysis of these compounds is challenging due to their ubiquitous presence in the laboratory and analytical instrumentation components.

PFC standards were purchased from Wellington Laboratories. A Shimadzu LCMS-8050 was used for analyte separation and mass spectrometry, flowing at 350 ?L/min through a Supelco Titan C18 column at 25C with a 12.7-minute binary gradient of 10 mM ammonium acetate in water and 10mM ammonium acetate in 80:20 MeOH:ACN. Analytes were ionized using negative mode electrospray ionization.

Creating a PFC-free environment required several adjustments to the standard LCMS workflow in both the way samples were prepared and data was acquired. Iterative modifications started with tubing replacements and LC hardware reconfiguration, which was followed by using glass and metal only for sample preparation. Even a seemingly minor adjustment such as inverting the autosampler vial septa proved important to reducing the PFC chemical background. Following these modifications the background reduced significantly making possible the acquisition of calibration curves measuring down to 1.25 fg on column with signal to noise levels of 378 for PFOA and 553 for perfluorooctane sulfonate (PFOS) and an area ratio between the low standard and background of 21.4:1 (PFOA) and no measured background for PFOS, n=5 for all measurements. The low standard %RSD value for PFOA is 0.526 and for PFOS is 4.12. Additional PFC analytes which will be added to this panel include perfluoro-n-butanoic acid, perfluoro-n-pentanoic acid, perfluoro-n-hexanoic acid, perfluoro-n-heptanoic acid, perfluoro-n-nonanoic acid, perfluoro-n-decanoic acid, perfluoro-1-butanesulfonate, and perfluoro-1-hexanesulfonate.