Determination of 1,4-dioxane in toluene by gas chromatography

A gas chromatographic method is presented for determining from 1 to 100 mu g/mL of 1,4-dioxane in toluene with purities ranging from commercial to high-purity grades. This method relies on extracting 1,4-dioxane from toluene into water. The water extract is analyzed for 1,4-dioxane content by gas chromatography/flame ionization detection and a capillary column coated with a bonded polyethylene glycol stationary phase. Splitless injection is used to achieve a 1 mu g/mL detection limit. Purging extracts with nitrogen after an initial analysis is suggested as an extract clean-up procedure and as a means to confirm the identification of 1,4-dioxane, However, for absolute identification of dioxane, gas chromatography/mass spectroscopy should be considered.