I have Litmus blue and Methyl orange here, both as a powder.
the litmus hardly seems soluble to any extent and leaves large particulate bits, the MO I havent tried at all.
now I realise these are used as ph indicators, any addvice on making up a soln for each that`s usable.
I`ve had them for Years now as part of a kids chem set that I bought for peanuts and has a few useful things in.
seems a pity to waste them!
btw, there`s .5g of litmus blue
1g of Methyl Orange.pantone159 - 4-1-2007 at 11:40
A prep for litmus indicator (forget from where):
Boil 10 g crushed litmus powder in 500 ml H2O for 5 minutes. Leave to stand, then filter.
I have a methyl red (similar to orange) solution that is 0.1% in water. I'd try something like that.Ozone - 4-1-2007 at 15:30
I have prepared methyl red and litmus, as well. Then filter papers are soaked, dried and cut (store in a dry place) to make test papers.
Additionally, in the US, the laxative Ex-Lax contained phenolphthalien as the primary component. I used to powder them, and dissolve to make a 1% mix
in ethanol. This is a great indicator with a sharp endpoint--no frills, effective and cheap (and used to be OTC; do Ex-Lax overseas still contain
phenolphthalien? this was replaced by a "safer" but "more gentle" natural ingredients.
Happy titrating!
O3
[Edited to reflect that new Ex-lax probably work quite well]
[Edited on 6-1-2007 by Ozone]unionised - 5-1-2007 at 05:03
I think the phenolphthalein in ex-lax has been replaced by senna in the UK too. On the other hand I think that before you say "was replaced by a
"safer" but uneffective "natural" ingredients"you ought to do some testing. Senna has been known for a long time and it certainly works.Ozone - 5-1-2007 at 19:29
Good Point!
Cassia is also being hawked as a weight loss supplement--Eew. Lose 10lb of crap by tomorrow, guaranteed! The anthroquinones present in the senna are
probably indicators as well (need to try this, to the drugstore for new-wave Ex-Lax I go).
Unfortunately, I do not have a couple of days free for quality assurance testing.
Besides, I'd need some old-school Ex-Lax for control purposes.
I have recently found that caffeic acid:Fe3+ complexes are very nice universal indicators--colorless or yellow at 2, blue/purple in varying degrees
for the intermediate range, and orange for the high range, viz. pH 9 and up.
Cheers,
O3guy - 5-1-2007 at 19:42
Can you dissolve it in some alcohol?Elawr - 5-1-2007 at 21:37
The spice tumeric makes a nice indicator. Just take some ground tumeric cooking spice and extract it with alcohol. Soak some white paper with the
solution and it dries to give you nice yellow indicator paper that turns red at high pH. The dye is relatively water-fast as well and very pretty.YT2095 - 6-1-2007 at 07:07
Quote:
Originally posted by guy
Can you dissolve it in some alcohol?
I was actualy thinking about doing that initialy as a way to extract the "good bits" from the junk, and then evap leaving the product.
I have boxes of universal indicator paper here, but sometimes it`s not always possible dip the paper into a reaction or just leave it float and wait
for it to change color (it leeches out in a min or 2).
I should be able to use my existing papers to make a buffer soln calibrated reasonably accurately using these papers though, Water based would be
ideal for the types of reactions I`m most likely to be doing anyway.
although as far as I can tell both litmus blue and meth orange seem to only indicate Basic materials, and I`de rather not have a buffer soln that
could react with the product either.
it only seems to be good if you can take samples that you can deep 6, but not much use for realtime reactions in situ.
thanks for the ideas each, and keep them coming, it`s certainly food for thought and Very Appreciated
Almost free litmus paper sub
Alchemist - 23-4-2009 at 11:11
Hello all,
Can't believe I have missed this for so long or have not seen it posted here! Found this on the net.
THE "GOLDENROD PAPER" SECRET (c)1996 William J. Beaty
--------------------------------------------------------------------
Office supply stores and Kinko's copy centers sell a type of paper called
Astrobrights(tm) Galaxy Gold. It's "goldenrod" in color, sort of a
yellow/orange. Big deal. However, IF ALKALINE SUBSTANCES HIT IT, IT TURNS
MAGENTA! Spray it with Windex, and it instantly turns bright red! Cool!!
Astrobrights Galaxy Gold paper is the worlds largest acid/base indicator
strip. Dip it in a base solution (like ammonia cleaner, baking soda
in water, etc.) and it turns bright red. Dip it in acid (vinegar, lemon
juice, etc.) and it turns yellow again.
(Note: there are other brands of goldenrod which do not work. If in
doubt, wet a sample of the paper with ammonia glass cleaner. Kinko's
usually has bottles of Windex around)
Update: I have found that the pH is 6.4 (yel) to 8.0 (red).
The fact that an 8.5 x 11 sheet of goldenrod is enormously larger than
your typical acid/base litumus paper test strip makes numerous classroom
demonstrations possible that never could be done before.
.
Besides, I'd need some old-school Ex-Lax for control purposes
.