Determination of low-level residual ethylene oxide by using solid-phase microextraction and gas chromatography.
Current methods of analysis for ethylene oxide (EO) in medical devices include headspace and simulated-use extractions followed by gas chromatography with either a packed or a capillary column. The quantitation limits are about 0.5-1.0 microg/g for a packed column and about 0.1-0.2 microg/g for a capillary column. The current allowable levels of EO on medical devices sterilized with EO gas as outlined in International Organization for Standardization (ISO) 10993-7 may be significantly reduced from current levels by applying the ISO Draft International Standard 10993-17 method for establishing allowable limits. This may require EO test methods with detection and quantitation limits that are much lower than those of the currently available methods. This paper describes a new method that was developed for the determination of low-level EO by solid-phase microextraction using the direct-immersion method. Factors such as temperature and stirring were found to affect absorption efficiency and absorption time. A low extraction temperature (about 6 degrees C) was found to be more efficient than room-temperature extraction. Stirring was found to reduce absorption time by about 50%. Under these conditions, detection and quantitation limits of 0.002 and 0.009 microg/g, respectively, were obtained by using a capillary column. As a result, this method makes compliance with lower EO limits feasible.
Ayoub
Kamal
K
Tyco/Healthcare-Kendall, DeLand, FL 32724, USA. kamal.ayoub@tycohealthcare.com
Harris
Leonard
L
Thompson
Bill
B
D002138:Calibration; D002849:Chromatography, Gas; D004202:Disinfectants / Q000032:analysis*; D005027:Ethylene Oxide / Q000032:analysis*; D007202:Indicators and Reagents; D012015:Reference Standards; D012996:Solutions; D013696:Temperature
D004202:Disinfectants; D007202:Indicators and Reagents; D012996:Solutions; D005027:Ethylene Oxide