Tashiro's indicator
{{Short description|pH 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{{cite book|last1=Willmes|first1=Arnold |title=Taschenbuch Chemische Substanzen|date=2007|publisher=|location=Frankfurt am Main|isbn=978-3817116621|page=|edition=}}[http://www.sigmaaldrich.com/catalog/product/fluka/36083 Tashiro’s indicator solution in ethanol][https://www.carlroth.com/downloads/sdb/en/2/SDB_2624_GB_EN.pdf SDS] or in methanol.[http://www.sigmaaldrich.com/catalog/product/fluka/35325 Tashiro’s indicator solution in methanol]
{{pH_indicator template|indicator_name=Tashiro's indicator|low_pH=4.4|high_pH=6.2|low_pH_color=purple|low_pH_text=white|high_pH_color=green|high_pH_text=white}} It can be used for the titration of ammonia in Kjeldahl analysis.
Colours
- In acids: violet
- At equivalence point (pH 5.2): grey
- In bases: green
Methylene blue functions to change the red-yellow shift of methyl red to a more distinct violet-green shift.
See also
References
{{Reflist}}{{Chem-stub}}