Appendix Acid Violet

Assay Determine as directed under Phenols, Appendix VI. Angular Rotation Determine as directed under Optical (Specific) Rotation, Appendix IIB, using a 100-mm tube. Phenols Shake 1 mL of sample with 20 mL of hot water. The water shows no more than a scarcely perceptible acid reaction with blue litmus paper. Cool the mixture, pass the water layer through a wetted filter, and treat the clear filtrate with 1 drop of ferric chloride TS. The mixture has only a transient gray-green color, but not a blue or violet color. 

Lead Determine as directed for Method I in the Atomic Absorption Spectrophotometric Graphite Furnace Method under Lead Limit Test, Appendix IIIB, using a 10-g sample. Methanol Transfer 1 drop of sample to a test tube, add 1 drop of 1 20 phosphoric acid and 1 drop of 1 20 potassium permanganate solution mix and allow to stand for 1 min. Add, dropwise, 1 10 sodium bisulfite solution until the permanganate color disappears. If a brown color remains, add 1 drop of the phosphoric acid solution. Add 5 mL of freshly prepared chromotropic acid TS to the colorless solution, and heat it in a water bath at 60° for 10 min. No violet color appears. 

Assay Dissolve about 200 mg, accurately weighed, in 3 mL of formic acid and 50 mL of glacial acetic acid, add 2 drops of crystal violet TS, and titrate with 0.1 A perchloric acid to a green endpoint or until the blue color disappears completely. Each mL of 0.1 A perchloric acid is equivalent to 8.710 mg of CgHi4N402. Lead A Sample Solution prepared as directed for organic compounds meets the requirements of the Lead Limit Test, Appendix IIIB, using 10 pg of lead ion (Pb) in the control. 

Carry out Method I for non-aqueous titration, Appendix VIII A, using 0.25 g dissolved in a mixture of 50 ml of anhydrous acetic acid and 0.5 ml of acetic anhydride and crystal violet solution as indicator. Each ml of 0.1m perchloric acid VS is equivalent to 15.74 mg of C H NjjHCl. 

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