Tashiro's indicator

Tashiro's indicator is a pH indicator (pH value: 4.4–6.2), mixed indicator composed of a solution of methylene blue (0.1%) and methyl red (0.03%) in ethanol  or in methanol. It can be used for the titration of ammonia in Kjeldahl analysis.

Colours
Methylene blue functions to change the red-yellow shift of methyl red to a more distinct violet-green shift.
 * In acids: violet
 * At equivalence point (pH 5.2): grey
 * In bases: green