Ethylene Glycol (C₂H₆O₂) Residual Analysis – GC-MS Method – ISO 10993-7 Annex B / Annex I

1. What is Ethylene Glycol (EG)?

Ethylene Glycol is a toxic by-product that may form during ethylene oxide (EO) sterilization due to the reaction of EO with moisture. With the chemical formula C₂H₆O₂, EG is a non-volatile, water-soluble compound and must be quantified as part of the EO residual analysis.

2. Standard Requirements (ISO 10993-7 Annex B & I)

• ISO 10993-7 provides specific limits for EO and ECH, but does not define a direct limit for Ethylene Glycol.

• EG is evaluated under “total EO-related residues” within Annex I – Toxicological Risk Assessment.

• Therefore, EG must be reported together with EO and ECH to assess total patient exposure.

3. Why Should EG Residues Be Measured?

• Can cause renal failure, metabolic acidosis and neurotoxicity

• Longer persistence on device surfaces compared to EO

• Essential for patient safety, CE marking, FDA submission and ISO 13485 compliance

4. GC-MS Method for Ethylene Glycol Residuals

Sample Preparation

• Aeration after EO sterilization

• Extraction with ultrapure water or methanol-water

• Transferred into GC vials

Typical GC-MS Parameters

Calculation

$$EG (mg/device) = \\frac{C \\times V \\times DF}{N}$$

5. Importance of EG Residual Testing

• Supports sterilization validation and biocompatibility evaluation

• Necessary for CE marking, FDA approvals and ISO 10993-17 toxicological evaluation

• Prevents patient exposure to toxic EO-related compounds

6. TTS Laboratory Services

At TTS Laboratory Services, we provide:
✔ EO, ECH, EG residual analysis by GC-MS
✔ Aeration validation & toxicological assessment
✔ ISO/IEC 17025 accredited reporting
✔ Compliance with ISO 10993-7 Annex B / Annex I