摘要：Ethylene oxide (EO) is widely used as sterilizer for many products including medical devices which are to be brought into direct contact with body fluid. Chemical change of EO in saline was investigated in relation to its residual toxicity. EO was dissolved in saline (pH 5.8) to give the final concentration of 500 μg/ml and the solution was warmed at 40°C for various periods. Formation of various compounds from EO and their quantitative changes were studied qualitatively and quantitatively by using gas-liquid chromatography, mass spectrometry and chemical test. Changes of the amounts with time for 24 hours of ethylene chlorohydrin (ECH) and ethylene glycol (EG), which are both members of the main products from EO in saline, were as follows : amount of EG was smaller than that of ECH for the initial 7.5 hours, and it was greater than that of ECH for the remainder of the experimental period. Amount of EG increased markedly from hour 16 and reached about 140 μg/ml at hour 21, while amount of ECH reached its maximum (50 μg/ml) at hour 16 and thereafter decreased gradually. The pH of the solution rose rapidly to about 10.3 for the initial 8 hours, and thereafter kept constant. These results suggest that EG was mainly formed directly from EO through the addition of H+ to EO for the early period, and that EG was mainly formed from ECH through the substitution of Cl in ECH by OH under basic conditions for the later peried. Formation of the two compounds which have not been reported to be formed from EO was found after hour 8. These compounds were identified as β-hydroxyethoxy acetaldehyde and its tautomer, monohydroxy dioxan. They seem to be formed by oxidation of diethylene glycol, which was produced by the addition of EO to EG, with air. As oxidation products of EG, glyoxal and glycolaldehyde monomer were detected after hour 8, and then glyoxylic acid, and glycolic acid were detected in a week. Acetaldehyde, rearrangement product of EO, was also detected.
