Bromophenol blue ACS, for microscopy

Indicator pH 3.0-4.6
Dissolve 0.1 g in 100 ml ethanol (20 %) or 0.04 g in 0.74 ml NaOH 0.1 mol/l and make up to 100 ml with water

Dyeing dead cells blue
Colour conversion yellow - blue
Transition range pH 3,0 - 4,6
Use vitality test of spermatozoa