additional water was added and the mixture allowed to cool to 50c the ph was adjusted to 5 5 6 5 with a 1 1 mixture of aqua ammonia and water to give an blue solution with a color value of 13 8 measured with a beckman du 650 uv visible spectrophotometer abs g l in methanol with a max abs of 621 nm the following examples are not considered the invention but were made as comparative examples for testing purposes to a 4 neck 1000 ml round bottom flask equipped with a thermometer condenser stirrer and a n 2 inlet was added muriatic acid 36 5 g water 4 8 g ortho formylbenzene sulfonic acid sodium salt 21 7 g aniline 10 eo 110 8 g and urea 2 2 g the ensuing mixture was heated to 95c for 3 hours under a n 2 atmosphere the reaction solution was then allowed to cool to 75 c and ammonium meta vanadate 0 14 g was added the ensuing reaction mixture was heated to 95c where a mixture of water 21 g and 35 hydrogen peroxide 21 g was slowly added after addition of the peroxide water solution the mixture was allowed to cool to ambient temperature the ph was adjusted to 4 3 with 50 sodium hydroxide solution water 137 g was then added to give a blue solution with a color value of 37 measured with a beckman du650 uv visible spectrophotometer abs g l in methanol and a max abs of 628 nm to a 4 neck 1000 ml round bottom flask equipped with a thermometer condenser stirrer and a n 2 inlet was added 93 sulfuric acid 9 3 g 1 3 benzenedisulfonic acid.