Determination of Polychlorinated Biphenyl (PCB) by GC/MS According to EPA Method 1628

Importance of the Topic

Polychlorinated biphenyls (PCBs) are persistent organic pollutants with high toxicity and stability in the environment. Despite being banned decades ago, PCBs continue to bioaccumulate in soil, sediment, and biota, posing risks to ecosystems and human health. Reliable analytical methods are essential for monitoring residual PCBs, ensuring regulatory compliance, and guiding remediation efforts.

Objectives and Study Overview

This study demonstrates the implementation of EPA Method 1628 for the determination of all 209 PCB congeners using low-resolution gas chromatography/mass spectrometry in selected ion monitoring (SIM) mode. An Agilent 8890 GC coupled to an Agilent 5977C GC/MSD was evaluated for its ability to calibrate 65 target congeners and screen the remaining 144 in sand and soil matrices, while meeting EPA criteria for linearity, resolution, and sensitivity.

Methodology

Samples of clean sand and native soil were prepared according to EPA extraction protocols. A nine-point calibration curve (5–1 000 ppb, n=3) was generated for 65 PCB congeners. Method blanks and system blanks were analyzed to verify absence of contamination. The method detection limit (MDL) was determined by eight replicates in sand. Soil samples were tested both unspiked and spiked at 10 ppb to assess recovery and matrix effects.

Instrumentation Used

• Gas Chromatograph: Agilent 8890 GC with multimode inlet (300 °C) and mid-column backflush.
• Column: Agilent J&W DB-5ms Ultra Inert, 30 m × 250 µm × 0.5 µm.
• Carrier Gas: Helium (constant flow at 1.0–1.2 mL/min).
• Mass Spectrometer: Agilent 5977C GC/MSD in SIM mode, 70 eV EI, source at 280 °C, quadrupole at 150 °C.
• SIM Groups: Seven time-segmented groups covering characteristic PCB ions (m/z 188–512).
• Oven Program: 50 °C (1 min), 12 °C/min to 240 °C (1.167 min), 5 °C/min to 320 °C (6 min).

Main Results and Discussion

Chromatographic separation of all 209 congeners and 32 labeled surrogates was achieved with baseline resolution, including critical separation of congeners 28 and 31 with valley height < 80% of the smaller peak. Signal-to-noise for congener 118 at 10 ppb exceeded 6:1 (requirement ≥ 3:1). Calibration curves for all 65 target congeners exhibited strong linearity (R2 > 0.991) and response factor RSDs < 11.4%. MDLs in sand ranged from < 0.01 to 0.4 ng/g, meeting method specifications. Spiked soil recoveries for the 65 congeners fell within 50–150%.

Benefits and Practical Applications

• High sensitivity and specificity for regulatory PCB monitoring programs.
• Ability to quantify 65 congeners while screening all 209 native PCBs.
• Robust performance in high-solid matrices such as sand and soil.
• Compliance with EPA Method 1628 criteria for linearity, resolution, and detection limits.

Future Trends and Opportunities

Advances in high-resolution mass spectrometry and multidimensional chromatography may further improve congener separation and identification. Automated sample preparation and miniaturized GC/MS platforms could enhance throughput and lower detection limits. Integration with data-processing software and AI-driven spectral deconvolution offers potential for rapid, comprehensive PCB profiling in complex environmental samples.

Conclusion

The Agilent 8890 GC paired with the 5977C GC/MSD effectively fulfills EPA Method 1628 requirements for quantifying and screening PCB congeners in sand and soil. The method delivers excellent linearity, sensitivity, and resolution, supporting reliable environmental monitoring and regulatory compliance.

References

1. United States Environmental Protection Agency. Learn about Polychlorinated Biphenyls. 2024.
2. United States Environmental Protection Agency. Method 1628: Polychlorinated Biphenyl (PCB) Congeners in Water, Soil, Sediment, Biosolids, and Tissue by Low-resolution GC/MS using Selected Ion Monitoring. July 2021.