Bromothymol blue

[cheltie]

Hi everyone,
Two of our bottles of bromothymol blue have turned an orange colour. It still works but we need some for a prac. test and I don't want them being confused by the colour. Any suggestions for getting it to turn blue again. They have only just been opened so shouldn't be off. I think we may have had this problem before but can''t remember what I did.
Thanks,
Helen.

[lada]

I have had that problem and did not have time to buy new one, so I added dropwise o.1M sodium hydroxide, until the bottle turned just green. It worked well- it turned yellow in acid and blue in alkali.

[cheltie]

Thanks Lada,
I'll give that a go and see how it works.
Helen

[rp]

Hi Helen
I actually discovered they had put the wrong indicator in the bottle.
Maybe you have one of that batch.
The supplier had been informed last year.
If you want some quick i can help out
Rhonda

[souj]

Mmm- this is a mystery,' cause I made some up fresh the other day using solid bromothymol blue according to the recipe in 'The Laboratory' and it turned out orange also! Works a treat but looks weird-what I want to know is-How come??!
Hope someone can shed some light!
Jodie