Estimation of Ethylene Oxide and 2-Chloroethanol in Spices and Oilseeds Using QuEChERS Extraction and GC/MS/MS

Significance of the Topic

Ethylene oxide (EtO) is widely used for sterilizing foodstuffs but is classified as carcinogenic, leading to regulatory bans in many regions. Its reaction product, 2-chloroethanol (2-CE), also poses health risks. Reliable trace-level measurement of these compounds in spices and oilseeds is critical for food safety monitoring and compliance with regulatory standards.

Goals and Study Overview

The primary objective of this work was to develop and validate a rapid, sensitive, and automated method for simultaneous detection and quantification of EtO and 2-CE in flaxseed, cumin powder, and red chili powder. The method employs QuEChERS extraction followed by GC/MS/MS analysis using a triple quadrupole system and aims to achieve limits of quantification (LOQs) at or below 10 ng/g in complex food matrices.

Methodology and Used Instrumentation

Sample Preparation:

• Approximately 2.00 g of homogenized sample hydrated with cold water.
• Extraction with 10 mL cold acetonitrile and extraction aids, followed by addition of QuEChERS salts (MgSO₄, NaCl, sodium citrate, disodium citrate sesquihydrate).
• Dispersive solid-phase cleanup using PSA, C18EC, and MgSO₄.
• Collection of the acetonitrile extract into GC vials for analysis.

Chromatographic and Detection Conditions:

• Agilent 8890 GC with G4513 autosampler.
• Agilent 7010 triple quadrupole MS in electron ionization mode.
• Column: Agilent J&W DB-VRX (60 m × 0.25 mm, 1.4 μm).
• Carrier gas: helium at 1.0 mL/min.
• Pulsed split injection (4:1), 2 μL injection volume, temperature programming from 90 °C to 250 °C.
• MRM transitions optimized for EtO (m/z 44>14, 44>28, 44>29, 80>31) and 2-CE (80>31, 80>43, 82>31).

Main Results and Discussion

Calibration and Linearity:

• Matrix-matched and solvent calibrations over 2–200 ng/mL yielded R² > 0.99 for both analytes in all matrices.

Limit of Quantification:

• LOQ established at 10 ng/g for EtO and 2-CE in flaxseed, cumin powder, and red chili powder.

Repeatability:

• Six replicate injections of 10 ppb matrix standards produced RSD values below 10% across all matrices.

Recovery:

• At spiked levels of 20 and 50 ng/g, average recoveries ranged from 75.6% to 86.6% for both compounds in all tested samples.

Benefits and Practical Applications

The developed method offers:

• High sensitivity and accuracy meeting EURL single-residue method requirements.
• Automated sample introduction for improved throughput and reproducibility.
• Reduced solvent usage and simplified workflow compared to acidic conversion techniques.
• Applicability to routine QA/QC laboratories monitoring EtO and 2-CE in food products.

Future Trends and Possibilities

Potential developments include:

• Extension to additional food matrices such as seeds, nuts, and dried herbs.
• Integration of isotopically labeled internal standards for further quantitation robustness.
• Miniaturized or portable GC/MS/MS platforms for field screening applications.
• Combination with high-resolution mass spectrometry to detect emerging sterilization by-products.

Conclusion

This study demonstrates a robust, sensitive, and reproducible QuEChERS-GC/MS/MS method for trace quantification of EtO and 2-CE in spices and oilseeds. Achieving LOQs of 10 ng/g, excellent linearity, precision, and recoveries, the approach is well-suited for regulatory compliance and routine food safety analysis.

References

• Dunkelberg H. Carcinogenic Activity of Ethylene Oxide and Its Reaction Products. Zbl. Bakt. Hyg. B. 1981;174:383–404.
• Tateo F, Bononi M. Determination of Ethylene Chlorohydrin as Marker of Spices Fumigation with Ethylene Oxide. J. Food Comp. Anal. 2006;19:83–87.
• Regulation (EU) 2015/868. Off. J. Eur. Union L 145:1–71.
• Regulation (EC) No 149/2008. Off. J. Eur. Union L 58:1–398.
• EURL-SRM Analytical Observation Report. Analysis of Ethylene Oxide and Its Metabolite 2-Chloroethanol by QuEChERS and GC–MS/MS. Dec 2020.