Ethylene Oxide Stock Solution

Ethylene Oxide Stock SolutionAll operations carried outin the preparation of these solutions must be conducted in a fume-hood. The operator must protect both hands and face by wearingpolyethylene protective gloves and an appropriate face mask. Storeall solutions in airtight containers at 4° to 8°. Carry out alldeterminations 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°, inject about 300 µL (corresponding to about 0.25 g) of liquid ethylene oxide into 50 mL of polyethylene glycol 200 R1. Determine the absorbed quantity of ethylene oxide by weighing before and after absorption (M_eo). Dilute to 100 mL with polyethylene glycol 200 R1. Mix well before use. Determine the exact concentration of ethylene oxide in the following manner.

Assay To 10 mL of 50% w/v suspension of magnesiumchloride in absolute ethanol add 20 mL of 0.1m ethanolichydrochloric acid VS, shake to obtain a saturated solution and allow to stand overnight to equilibrate. Weigh 5 g of the solution being examined into the flask and allow to stand for 30 minutes. Titrate with 0.1m ethanolic potassium hydroxideVS, determining the end point potentiometrically, Appendix VIII B. Carry out a blank titration using polyethylene glycol 200 R1 in place of the substance being examined. The ethylene oxide concentration in mg per g is given by the expression 4.404(V₀ – V₁)/m, where V₀ and V₁ are the volumes of ethanolic potassium hydroxide used respectively for the blank titration and the assay and m is the weight of sample taken, in g.