The selection of developing solvents in rapid detection of illegally additives in hair coloring agent

Weigh out 50 mg of the reference substance in a standard 10 ml flask. Add 5 ml of 96% ethanol and 250 mg of ascorbic acid. Make the solution alkaline by addition of the ammonia solution to give an apparent pH of 10 (test with indicator paper). Make up to 10 ml with 96% ethanol and mix (The rules governing cosmetic products in the European Union Cosmetic products Methods of Analysis, 1999).