摘要：A colorimetric determination of ethylene oxide (EO) and a trapping procedure of residual EO in medical devices were studied. In the trapping procedure, EO-sterilized samples were introduced into a heating chamber and heated at 70°C under nitrogen gas flow at 100 ml/min for three hours. The desorbed EO was trapped by two impingers in series, which contained 10 ml of 5 N sulfuric acid solution, and the impingers were allowed to stand for one hour at room temperature. The aliquots of the contents were collected from each of the impingers, adjusted to pH 5 and used as test solutions for EO determination. In the colorimetric determination for EO, 4 ml of trisodium paraperiodate solution acidified to pH 5 were added to the test solutions and allowed to react for 30 minutes at room temperature. To this, 2 ml of 3-methyl-2-benzothiazolinone hydrazone hydrochloride solution were added and allowed to react for 30 minutes at room temperature. Further 30 ml of mixed solution of ferric chloride and sulfamic acid were added and after 10 minutes the solution was diluted to 100 ml with water. Absorbance was measured at 628 nm. EO recovery of 98% was obtained by using this colorimetric determination and trapping procedure.
