Ethylene Oxide Stock Solution

All operations carried out in the preparation of these solutions must be conducted in a fume cupboard. The operator must protect both hands and face by wearing polyethylene protective gloves and an appropriate face mask.

Store all solutions in an airtight container in a refrigerator at 4 °C to 8 °C. Carry out all determinations three times.

Into a dry, clean test-tube, cooled in a mixture of 1 part of sodium chloride and 3 parts of crushed ice, introduce a slow current of ethylene oxide gas, allowing condensation onto the inner wall of the test-tube. Using a glass syringe, previously cooled to -10 °C, inject about 300 µL (corresponding to about 0.25 g) of liquid ethylene oxide into 50 mL of macrogol 200 R1. Determine the absorbed quantity of ethylene oxide by weighing before and after absorption (M_eo). Dilute to 100.0 mL with macrogol 200 R1. Mix well before use.

Assay To 10 mL of a 500 g/L suspension of magnesium chloride in anhydrous ethanol add 20.0 mL of 0.1 M alcoholic hydrochloric acid in a flask. Stopper and shake to obtain a saturated solution and allow to stand overnight to equilibrate. Weigh 5.00 g of ethylene oxide stock solution (2.5 g/L) into the flask and allow to stand for 30 min. Titrate with 0.1 M alcoholic potassium hydroxide determining the end-point potentiometrically (2.2.20).

Carry out a blank titration, replacing the substance to be examined with the same quantity of macrogol 200 R1.

Ethylene oxide content in milligrams per gram is given by: