Determination of Dioxin in Food by GC-MS/MS Coupled with Boosted Efficiency Ion Source (BEIS)

Importance of the Topic

Dioxins, comprising polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), are highly toxic environmental contaminants that persist and bioaccumulate in food chains. Their trace‐level determination in food matrices requires exceptional sensitivity and selectivity, traditionally achieved by GC‐HRMS. The development of a faster, cost‐effective alternative based on GC‐MS/MS with enhanced ion source efficiency addresses growing regulatory and public health demands.

Objectives and Overview

This study aimed to establish and validate a multiple reaction monitoring (MRM) method for quantifying 17 toxic PCDD/F congeners in food samples using the Shimadzu GCMS-TQ8050 NX coupled with a Boosted Efficiency Ion Source (BEIS). Method performance was assessed through calibration curves, relative response factors (RRFs), accuracy tests at low concentration levels, and comparison of toxic equivalents (TEQs) against consensus values from the Norwegian Institute of Public Health (NIPH).

Methodology and Used Instrumentation

Sample preparation followed EPA-1613B, involving:

• Spiking homogenized food samples with 13C-labeled surrogate standards.
• Solvent extraction and gravimetric lipid determination.
• Cleanup on multilayer silica, basic alumina, and carbon columns.
• Elution of the PCDD/F fraction with toluene, evaporation, and addition of volumetric standard.

Instrumental conditions:

• GCMS-TQ8050 NX triple quadrupole MS with BEIS for improved ionization.
• Column: DB-5 MS, 60 m × 0.25 mm × 0.25 μm.
• Oven program ramping from 120 °C to 310 °C over multiple segments.
• Carrier flow: constant 1.5 mL/min; injection volume: 2 μL; EI mode at 70 eV.
• MRM acquisition with transitions optimized for each congener; loop time 1.4 s.

Main Results and Discussion

Calibration and RRFs:

• Seven‐point calibration from 0.01 to 10 ng/mL for TCDD/F congeners.
• Average RRFs between 0.91 and 1.39, with relative standard deviations ≤ 12%.

Accuracy and precision:

• Quantitation at the low CSLQ×2 level yielded relative errors below 20% for all analytes.

Real sample validation:

• Analysis of various food types supplied by NIPH demonstrated TEQ values in close agreement with published consensus, confirming method reliability.

Benefits and Practical Applications

The BEIS‐enhanced GCMS-TQ8050 NX method offers:

• High sensitivity and selectivity comparable to GC-HRMS at reduced cost and complexity.
• Robust accuracy and reproducibility for regulatory compliance testing.
• Streamlined workflow suitable for routine food safety laboratories.

Future Trends and Applications

Advances may include integration with automated sample preparation, expansion to other persistent organic pollutants, and coupling with high‐throughput screening platforms. Further improvements in ion source technology and data processing algorithms could push detection limits lower, supporting wider environmental and clinical surveillance.

Conclusion

The established GC-MS/MS MRM method using Shimadzu GCMS-TQ8050 NX with BEIS achieves reliable quantitation of PCDD/Fs in food at trace levels. It demonstrates excellent linearity, accuracy, and agreement with reference TEQ values, positioning this approach as a practical alternative to high‐resolution mass spectrometry for routine dioxin analysis.