A Fast Method for EPA 8270 in MRM Mode Using the 7000 Series Triple Quadrupole GC/MS

Significance of the Topic

A rapid and sensitive analytical method for semivolatile organic compounds is essential for environmental monitoring, regulatory compliance, and industrial quality control. By leveraging multiple reaction monitoring (MRM) on a triple quadrupole GC/MS system, laboratories can achieve lower detection limits, enhanced selectivity, and faster sample throughput compared with traditional scan or SIM modes.

Objectives and Study Overview

This study describes the development and validation of a 10-minute GC/MS method in dynamic MRM (dMRM) mode for EPA Method 8270D/E. The primary goals were to extend the calibration range from 0.02 to 160 ppm in a single run, improve sensitivity and selectivity, and demonstrate reproducible performance across multiple instruments.

Methodology and Instrumentation

• Gas Chromatograph: Agilent 8890 or 7890B equipped with a split/splitless inlet and 9 mm LPD inlet liner.
• Column: Agilent J&W DB-5ms Ultra Inert, 20 m × 0.18 mm, 0.18 µm film thickness.
• Injection: 1 μL in split mode (1:20), inlet temperature 280 °C.
• Oven Program: 40 °C to 320 °C at 35 °C/min, total run time 10 min.
• Mass Spectrometer: Agilent 7000C/D triple quadrupole, EI source at 300 °C, quadrupoles at 150 °C.
• Acquisition: Dynamic MRM with 6.6 cycles/s, optimized dwell times and delta retention windows for 77 analytes plus six deuterated internal standards.
• Calibration: Twelve to thirteen levels from 0.02 to 160 ppm in dichloromethane; ISTDs at 4 ppm. Data processed with MassHunter Quantitative Analysis.

Main Results and Discussion

• All 77 target compounds were baseline separated within 10 min, with exemplary resolution of isomeric fluoranthene and benzo[b/k]fluoranthene.
• Working calibration range achieved: 0.02 to 160 ppm; low-end detection at 0.02 ppm is tenfold below common protocol requirements.
• Initial calibration performance: 68 of 77 compounds met average RF %RSD ≤20%; overall batch average RF %RSD was 12.3%, and average ISTD RF %RSD was 13.5%.
• Linear regression (R2 ≥0.99) was sufficient for most analytes; five challenging compounds required quadratic fits.
• Dynamic MRM eliminated matrix interference, reduced review time, and maintained high sensitivity (3–5 × 107 counts at highest standard).

Benefits and Practical Applications

• High throughput environmental screening and compliance testing with a single 10 min method.
• Reduced calibration frequency and operational costs due to low RF %RSD and extended continuing calibration stability.
• Applicable to EPA 8270D/E and adaptable to international semivolatile methods.

Future Trends and Applications

Ongoing developments may include automated sample preparation, expanded compound libraries for emerging contaminants, integration of machine learning for data review, and coupling with high-throughput inlet technologies to further accelerate GC/MS workflows.

Conclusion

The developed MRM-based GC/MS method on the Agilent 7000 series provides a rapid, robust, and highly selective platform for semivolatile analysis. With a broad calibration range, excellent reproducibility, and compliance with EPA 8270D/E criteria, this approach enhances laboratory productivity and data quality.

Instrumentation Used

• Agilent 8890 or 7890B GC with split/splitless inlet and LPD liner
• Agilent J&W DB-5ms Ultra Inert column (20 m × 0.18 mm, 0.18 µm)
• Agilent 7000C/D triple quadrupole GC/MS
• MassHunter Workstation Quantitative Analysis software

References

1. EPA 8270 Re-optimized for Widest Calibration Range on the 5977 Inert Plus GC/MSD, Agilent Technologies Application Brief, publication number 5994-0350EN, 2018.