title: Gas chromatographic determination with electron capture detection of residual ethylene oxide in intraocular lenses.
abstract: A sensitive method is described to determine trace quantities of ethylene oxide (EO) in EO-sterilized intraocular lenses (IOLs). An IOL is dipped in ethanol containing 0.25 ppm propylene oxide (PO) in a 4 mL vial, 2 drops of freshly distilled hydrobromic acid is added through a septum, and the mixture is warmed at 50 degrees C for 24 h. It is then neutralized by vigorous shaking with sodium bicarbonate, dehydrated with anhydrous sodium sulfate, and filtered. The filtrate is injected into a gas chromatograph with electron-capture detection, and the peak height ratio of ethylene bromohydrin/propylene bromohydrin is measured. EO residue is calculated from the calibration curve obtained through a similar procedure with the standard EO/PO solutions. The limit of determination is 0.04 microgram/lens (ca 2.0 ppm). When EO residue levels were determined for IOLs sampled at 3 different aeration periods after sterilization, we found that 9 days of aeration was necessary to meet the U.S. Food and Drug Administration proposed limit for EO residue in IOLs.
authors.affiliation: National Institute of Hygienic Sciences, Division of Medical Devices, Tokyo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Kikuchi
authors.forename: A
authors.initials: A
authors.lastname: Nakamura
authors.forename: K
authors.initials: K
authors.lastname: Tsuji
mesh_terms: D002849:Chromatography, Gas; D004563:Electrochemistry; D005027:Ethylene Oxide / Q000032:analysis*; D007202:Indicators and Reagents; D007910:Lenses, Intraocular; D013242:Sterilization
chemical_list: D007202:Indicators and Reagents; D005027:Ethylene Oxide