Analysis of Perfluoroalkyl and Polyfluoroalkyl Substances in Water by Direct Injection LC-MS/MS

Polyfluoroalkyl Substances (PFAS) in the Environment
Poster Presentation

Prepared by , F. Qin

Contact Information: jingcun.wu@perkinelmer.com; 1 905 266 3451


ABSTRACT

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are synthetic compounds, widely used in industrials and consumer products. There is growing health concerns to these chemicals due to their highly toxic persistent properties. The widely used method for PFASs analysis is LC-MS/MS due to its high sensitivity and selectivity. Coupling SPE with LC-MS/MS is a popular approach and is employed in EPA methods. Recently, a high throughput method for monitoring PFASs has been appreciated using direct injection without SPE, which not only achieves high sample throughput, reduces time and cost, but also minimizes analyte loss and contamination from SPE processes, as demonstrated by this study using QSight 420 mass spectrometer coupled with UHPLC for trace PFASs analysis in drinking and surface water samples.

Good linearity was obtained for each analyte from low ng/L to 2000 ng/L with regression coefficients (R2) greater than 0.99. The limit of quantification of the method was estimated based on signal to noise ratio (S/N ≥ 10) of analyte’s quantifier ion and ranged from 0.5 ng/L for PFOS to 40 ng/L for PFHxDA. For QC samples, after isolating the LC system contaminates by a delay column, no other interference or contamination from reagents and glassware was observed. Analyte recoveries from the spiked river water samples are between 70.2 to 119%, demonstrated good accuracy of the method. The method was applied for the analysis of PFASs in 15 water samples including drinking water, rainwater, river water and lake water samples. Among the seventeen PFAS compounds studied, six of them were found from river water, lake water and some tap water samples, although their amounts are much lower than any of the drinking water health advisory limits. The identity of the analytes in these samples was confirmed by comparing the analyte retention time and the ion ratios of the qualifier ion against quantifier ion in the samples with those in the reference standards. These results demonstrated the superior sensitivity and selectivity of the QSight 420 LC-MS/MS system for analysis of PFASs in water.