Double Sequential enzyme reaction
Green to brown
Diazo reaction
Tan or pink to violet
Sodium nitroprusside reaction
Purple
pKa change of a polyelectrolyte
Blue to Yellow
Proteins (Sorrensen's) Error of indicators
Blue
Double indicator system
Orange to Blue
Pseudoperoxidase activity of hemoglobin
Uniform green & blue
Ehrlich reaction
Red
Greiss reaction
Uniform Pink
Leukocyte esterase
Purple