C6H6Cl6 290.83

Cyclohexane,1,2,3,4,5,6-hexachloro-,(1a,2a,3b,4a,5a,6b)-.
g-1,2,3,4,5,6-Hexachlorocyclohexane [58-89-9].

Packaging and storage— Preserve in well-closed containers.

USP Reference standards á11ñ— USP Lindane RS.

Identification,Infrared Absorption á197Kñ.

Congealing temperature á651ñ: not less than 112.0.

Water,Method Iá921ñ: not more than 0.5%.

Chloride ion— Place about 100mg in a test tube with 10mLof water,shake,and filter.Add 1mLof nitric acid and 3mLof silver nitrate TSto the filtrate:no turbidity develops.

Assay— Transfer about 400mg of Lindane,accurately weighed,to a wide-mouth,glass-stoppered,250-mLconical flask,add 20mLof alcohol,and warm on a steam bath until solution is complete.Cool,add 20mLof a 1in 20solution of potassium hydroxide in alcohol,swirl gently,and allow to stand for 10minutes.Dilute with water to about 100mL,neutralize with 2Nnitric acid,and add 5mLin excess.Pipet into the solution 50mLof 0.1Nsilver nitrate VS,then add 5mLof nitrobenzene,and shake vigorously.Add ferric ammonium sulfate TS,and titrate the excess silver nitrate with 0.1Nammonium thiocyanate VS.Perform a blank determination (see Residual Titrationsunder Titrimetry á541ñ).Each mLof 0.1Nsilver nitrate is equivalent to 9.694mg of C6H6Cl6.

Expert Committee:(PA7)Pharmaceutical Analysis 7

USP28–NF23Page 1136

Phone Number:1-301-816-8394