Analysis of Residual Ethylene Oxide in Medical Devices by Headspace Gas Chromatography (Water Extraction)

Significance of the Topic

Ethylene oxide sterilization is widely used in medical device manufacturing due to its ability to penetrate materials and inactivate microorganisms. Residual ethylene oxide poses health risks, making reliable analytical methods essential for ensuring product safety and regulatory compliance.

Objectives and Study Overview

This study establishes and evaluates a headspace gas chromatography method using water as an extraction solvent to quantify residual ethylene oxide in medical devices. The approach adheres to JIS T 0993-7:2012 and ISO 10993-7:2008 guidelines, aiming to deliver an environmentally friendly and cost-effective analytical solution.

Methodology

Samples including sterilized bandages and suction catheters were prepared by cutting defined pieces and extracting ethylene oxide in water containing a propylene oxide internal standard. Calibration standards ranged from 0.4 to 2.0 micrograms per milliliter. Headspace equilibrium and analysis conditions were optimized for sample temperature, pressure, and timing to ensure reproducibility.

Instrumentation Used

• Gas chromatograph: Nexis GC-2030 equipped with FID-2030 flame ionization detector
• Headspace sampler: HS-20
• Analytical column: SH-Stabilwax, 30 m length, 0.53 mm id, 2 μm film
• Carrier gas: nitrogen at constant linear velocity

Main Results and Discussion

System performance exceeded JIS criteria: resolution between ethylene oxide and internal standard above 3.3; peak tailing factors below 1.1; calibration curve correlation coefficient of 0.9997; detection limit around 0.03 µg/mL; quantification limit near 0.1 µg/mL. Residual ethylene oxide in bandages averaged 0.435 µg per 0.5 g sample, while levels in catheters were below detection.

Practical Benefits and Applications

The water extraction protocol offers a safer, more economical, and eco-friendly alternative to organic solvents. Its high precision and sensitivity make it suitable for routine quality control in medical device manufacturing, supporting regulatory compliance and risk management.

Future Trends and Potential Applications

Integration of multi-analyte headspace methods could enable simultaneous monitoring of ethylene oxide byproducts such as ethylene chlorohydrin and ethylene glycol. Advances in automated sample handling may further improve throughput. Development of greener reagents and microextraction technologies will enhance sustainability.

Conclusion

The validated HS-GC method using water extraction provides a robust and environmentally conscious approach for quantifying residual ethylene oxide in medical devices. The Shimadzu GC-2030 with HS-20 meets stringent performance requirements, offering reliable data for product safety assurance.

Reference

• ISO 10993-7:2008 Biological evaluation of medical devices Part 7 Residual ethylene oxide test methods
• JIS T 0993-7:2012 Test for residual ethylene oxide in medical devices
• Shimadzu Application News 01-00139-EN First Edition Apr 2021
• Shimadzu Application News No G 336