j_sum1 - 8-6-2021 at 03:03
It arrived today: about 10g. It was a freebee -- I was able to choose between a few different stains and indicators and chose something that I did
not have.
Based on the wiipedia page, it seemed to me that it could be good as a test for calcium ions: kind of fun to have on hand. I can see applications for a
specific spot test for Ca2+ and I think with some experimentation I should get there. It is used as a histology stain to highlight bones and has
fluorescent properties also.
I have not had a good play with it yet: just dissolved some in water and tried a couple of test tubes. I am not seeing a particularly dramatic colour
change with Ca, but I probably need to control the pH. I am wondering if it makes other lake pigments with different cations. That could be an
interesting experiment. (Or maybe fruitless).
I have discovered that it acts as a pretty vivid pH indicator. I am not sure how narrow the transiton range is yet, but it goes from lemon yellow in
acidic conditions through red to bright violet in alkali. Vibrant enough to be fun.
Anyway, if anyone has experience of this or other alizarins, I would love to know more.
J.
teodor - 8-6-2021 at 03:52
Sodium Alizarin Sulfonate (alizarin red S) gives a dark reddish violet compound with Zr salts and a red compound with Al salts.