Determination of flame retardants by Gas Chromatography Mass Spectrometry

Importance of the Topic

The regulation of flame retardants such as polybrominated biphenyls (PBBs) and polybrominated diphenyl ethers (PBDEs) is critical for minimizing their release during manufacturing, use, and disposal of electrical and electronic equipment. Accurate quantification supports compliance with the Restriction of Hazardous Substances Directive (RoHS) and helps protect human health and the environment.

Objectives and Study Overview

This application note demonstrates a fast and reliable gas chromatography–mass spectrometry (GC-MS) method to separate, identify, and quantify ten PBB congeners and ten PBDE congeners in standard mixtures. The study focuses on method optimization, sensitivity, linearity, and repeatability using a Scion 456 GC coupled to a Scion single quadrupole MS.

Methodology and Instrumentation

The analysis employed the following conditions:

• Gas chromatograph: Scion 456 GC
• Mass spectrometer: Scion single quadrupole MS operated in full-scan (100–1000 Da) and selected ion monitoring (SIM) modes
• Column: Scion-5HT, 15 m × 0.25 mm × 0.10 µm
• Oven program: 110 °C (2 min), ramp at 40 °C/min to 200 °C, 10 °C/min to 260 °C, 20 °C/min to 340 °C (2 min)
• Injector and transfer line: 280 °C and 300 °C, respectively
• Ion source: 230 °C
• Carrier gas: Helium at 1 mL/min (constant flow)

Standard stock solutions of PBBs and PBDEs were prepared at 20 µg/mL in toluene. Five working standards (0.05–0.45 µg/mL) were generated by serial dilution for calibration.

Main Results and Discussion

The total ion chromatograms for 20 µg/mL PBB and PBDE standards displayed clear separation of all congeners within a 15-minute run time. Retention times ranged from 3.36 to 14.73 minutes. Calibration curves in SIM mode exhibited excellent linearity (R² ≥ 0.995) over 0.05–0.45 µg/mL. Repeatability (n=10 at 0.05 µg/mL) yielded relative standard deviations between 0.005% and 0.03%, confirming method precision.

Benefits and Practical Applications

• High throughput: 15-minute analysis for twenty congeners
• Excellent sensitivity and precision for regulatory compliance
• Straightforward sample preparation via dilution in toluene
• Adaptable to routine monitoring in QA/QC and environmental laboratories

Future Trends and Potential Applications

Advances in high-temperature GC columns and tandem mass spectrometry (GC-MS/MS) promise even lower detection limits and improved selectivity. Automation of sample preparation and data processing will enhance laboratory throughput. Application to complex matrices such as e-waste leachates and consumer goods is a logical next step to ensure compliance and environmental safety.

Conclusion

The optimized Scion GC-MS method achieves rapid, reliable, and reproducible quantification of PBBs and PBDEs. High linearity and low variability support its use for routine analysis and regulatory monitoring under RoHS guidelines.