Performance Assessment of GC–Orbitrap HRMS for Ultra-Trace PCDD/F Determination in Soil

Emerging Environmental Applications for High Resolution Mass Spectrometry
Poster Presentation

Presented by A. Fornadel
Prepared by D. Roberts1, P. Benedetti2
1 - Thermo Fisher Scientific, TFS, Boundary Park, Hemel Hempstead, Non-U.S., H25 5tg, United Kingdom
2 - Thermo Fisher Scientific, TFS Milan, Segrate, Segrate, Non-U.S., Milan, Italy


Contact Information: [email protected]; 07500578124

ABSTRACT

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) are highly toxic persistent organic pollutants routinely monitored in environmental matrices due to their long-term ecological and human health impacts. Soil presents a particularly challenging analytical matrix because of its heterogeneity and the potential for co-extracted interferences. Regulatory methods such as EPA Method 1613 mandate high sensitivity, selectivity, and minimum mass resolving power to ensure reliable quantification at ultra-trace concentration levels. Advances in high-resolution mass spectrometry provide opportunities to improve analytical performance while maintaining regulatory compliance for environmental laboratories.
PCDD/F analysis was performed using gas chromatography coupled to an Orbitrap high-resolution mass spectrometer operated at 60,000 resolving power (FWHM at m/z 200). Soil samples were processed using established EPA Method 1613 workflows, including extraction and multi-column cleanup to minimise matrix interferences. Instrument control, data acquisition, quantification, and regulatory reporting were performed using Chromeleon CDS with an integrated dioxin analysis workflow to support automated and compliant data processing.
Calibration performance was evaluated using an 11-point calibration curve with three replicate injections at 15 fg on-column. Calibration linearity was congener dependent, with lighter congeners exhibiting the highest linearity, while higher chlorinated congeners such as OCDD and HpCDF showed reduced, but acceptable coefficients of determination, at the highest calibration levels, likely due to over-response at elevated on-column masses. Despite this, response factor variability remained low, with %RSD values meeting EPA Method 1613 acceptance criteria of ≤20%, and comparable or improved performance relative to more stringent requirements in other regulatory methods.
Instrument sensitivity was demonstrated with reliable detection down to 10–15 fg on-column. Soil spike replicates at 15 fg on-column showed %RSD values below 7% for 2,3,7,8-TCDD, with ion ratio confirmation achieved for most target congeners. Performance check standards at LOQ/2 and LOQ/4 further confirmed stable ion ratios and confident congener identification within regulatory tolerances.
This work demonstrates that GC–Orbitrap high-resolution mass spectrometry can meet or exceed EPA Method 1613 performance requirements for PCDD/F analysis in soil, providing enhanced sensitivity, robust calibration performance, and increased confidence in routine environmental monitoring.