Identification and quantification of ethylene oxide in sterilized medical devices using multiple headspace GC/MS measurement

•A multiple HS/GC–MS measurement of residual EO present in sterilized plastic samples is proposed.•The quantification of EO is done, according to the ISO 10993-7 standard, adding EO amounts extracted for each repeated extractions.•The specificity of the detection of EO regarding acetaldehyde (structural isomer of EO) which may be formed from EO is ensured.•Extraction conditions to maximize the amount of extractible EO are given for different type of plastics.•A method validation and an inter-laboratory reproducibility study had been performed for COC samples.•Results obtained for 70 medical devices controlled during a market survey are reported. This manuscript, based on the ISO 10993-7 approach, describes a multiple HS-GC measurement of residual EO present in sterilized plastic samples. The quantification of EO is done, according to the ISO standard, by addition of EO amounts extracted for each repeated extraction. During the method development, the specificity of the detection of EO regarding acetaldehyde (structural isomer of EO) which may be formed from EO has been ensured and different tests were performed to check a possible influence of the sample preparation. Assays to maximize EO extraction were performed for different materials (Cyclo-olefine Copolymer (COC), Cyclo-olefine Polymer (COP), Silicon, Polyurethane (PUR)) changing extraction temperatures and times for the headspace and the pre-thermal treatment. Results highlight that depending on the material, EO can be more or less retained and thus thermal extraction conditions to maximize the amount of extractible EO from plastics may change accordingly. For COC syringes a validation according to ICH guidelines and an inter-laboratories study were performed. The method has been used for a market survey of EO sterilized medical devices, results obtained are reported in this manuscript.