Standard preparation— Transfer 0.50mLof water to a dry 100-mLvolumetric flask,dilute with dehydrated isopropyl alcohol to volume,and mix.

Chromatographic system— Under typical conditions,the gas chromatograph is equipped with a thermal conductivity detector,and contains a 1.5-m ×6-mm stainless steel column containing packing S4.The column is maintained at a temperature of 180,and helium is used as the carrier gas.

Procedure— Inject 5.0µLof Standard preparationinto a suitable gas chromatograph,and determine the area under the water peak.Similarly inject 5.0µLof the same dehydrated isopropyl alcohol to provide a blank,and determine the area under the water peak.The retention time is about 1minute.Similarly inject 5.0µLof Acetone.The area under the water peak for Acetone is not greater than that from the Standard preparationcorrected for the area under the water peak in the blank chromatogram (0.5%).

Chromatographic system— Under typical conditions,the instrument is equipped with a flame-ionization detector,and contains a 3-mm ×1.8-m column containing packing S4.The column temperature is programmed at a rate of about 8per minute from 110to 220,and helium is used as the carrier gas.

Procedure— Inject a suitable volume,typically about 0.5µL,of Acetone into a suitable gas chromatograph,and record the chromatogram.Calculate the percentage of C3H6Oin the Acetone,on the anhydrous basis,by dividing the area under the acetone peak by the sum of the areas under all of the peaks and multiplying by 100.[NOTE—No separate correction is applied for water content,since water does not respond to the flame-ionization detector.]