LC/MS, LC/MS/MS, LC/QQQ
IndustriesEnvironmental
ManufacturerThermo Fisher Scientific
Significance of the Topic
Perfluorinated compounds (PFCs) are persistent environmental pollutants characterized by strong C–F bonds and high chemical stability. Their resistance to degradation leads to bioaccumulation in water, wildlife and humans, raising concerns for public health and environmental safety. Sensitive and rapid analytical methods are essential for monitoring trace levels of PFCs in drinking water and groundwater.
Objectives and Study Overview
This study aimed to develop and validate a direct injection LC–MS/MS method for simultaneous analysis of 17 PFCs using the Thermo Scientific TSQ Altis triple quadrupole system. Key performance metrics included limits of detection (LOD), limits of quantification (LOQ), linearity, precision and applicability to real water samples.
Methodology
Water samples (1 mL) were centrifuged at 12 000 rpm for 5 min and filtered through a 0.22 µm membrane. Chromatographic separation was achieved on a C18 trap column (50 × 2.1 mm, 2.6 µm) followed by an Accucore aQ C18 analysis column (100 × 2.1 mm, 2.6 µm) with a binary gradient of 10 mmol/L ammonium acetate in water (A) and methanol (B) at 0.3 mL/min. Injection volume was 10 µL.
Instrumentation Used
- UHPLC: Thermo Scientific Vanquish series
- Mass spectrometer: Thermo Scientific TSQ Altis triple quadrupole
- Ion source: H-ESI II in negative mode (spray voltage 3 kV, sheath gas 50 arb, auxiliary gas 10 arb, aux gas temp 400 °C, capillary 320 °C)
- Columns: Thermo Scientific Accucore C18 Trap and Accucore aQ C18
Main Results and Discussion
LOD values for all 17 PFCs ranged from 1 to 10 pg/mL and LOQs from 2 to 20 pg/mL, meeting EPA Method 537 requirements. Calibration curves exhibited excellent linearity (2–500 pg/mL) with correlation coefficients (r) above 0.99. Six consecutive injections of a 20 pg/mL standard mix demonstrated peak area RSDs below 5.1%. Application to tap and groundwater samples confirmed the method’s robustness: PFOA was detected in tap water, while groundwater served as a blank matrix spiked at 20 pg/mL, yielding RSDs ≤ 6.3%.
Benefits and Practical Applications
- Direct injection reduces sample preparation time and solvent consumption
- High selectivity and sensitivity enable trace-level quantification
- Wide linear range supports regulatory compliance and routine monitoring
- Excellent reproducibility facilitates high-throughput environmental analysis
Future Trends and Applications
Advances may include coupling with high-resolution mass spectrometry for non-target screening, automated sample injection systems for enhanced throughput, microfluidic front ends for reduced sample volumes, and integration into on-site monitoring platforms. Emerging interest in broader PFAS classes will drive method adaptation and expanded compound libraries.
Conclusion
The developed direct injection LC–MS/MS method on the TSQ Altis platform provides a rapid, sensitive and reliable approach for simultaneous determination of 17 PFCs in environmental waters. It satisfies regulatory criteria, offers excellent precision and linearity, and is well suited for routine monitoring of trace perfluorinated contaminants.
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