Bromothymol Blue not working

Peter Sigsworth

COMMITTEE
I bought some Bromothymol Blue from scichem
upload_2020-2-25_9-47-45.png

Isn't it supposed to go yellow in acid conditions?
Here is the colour with 10ml of 1M HCl
upload_2020-2-25_9-49-19.png

Is it a duff batch?
 

Peter Sigsworth

COMMITTEE
Something is obviously wrong here Peter. It should, as you say, go yellow in acid, green in neutral and blue in basic.:)
You're telling me!!!! - I got it a few months ago and haven't used it until today (as you can see still in well date) - surely someone else has had the same problem by now and told them????
 
You're telling me!!!! - I got it a few months ago and haven't used it until today (as you can see still in well date) - surely someone else has had the same problem by now and told them????
We prefer to make up our indicators ourselves from the powder. A year or so ago we ordered Benzoyl Chloride for a practical - but the practical didn't work so we suspected that the bottle marked Benzoyl Chloride was not Benzoyl Chloride. We analysed it by FT-IR and 1H NMR and found out that it was Benzyl Chloride. The suppliers were grarteful as they didn't have the facilities to analyse this particular batch.:)
 
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We prefer to make up our indicators ourselves from the powder. A year or so ago we ordered Benzoyl Chloride for a practical - but the practical didn't work so we suspected that the bottle marked Benzoyl Chloride was not Benzoyl Chloride. We analysed it by FT-IR and 1H NMR and found out that it was Benzyl Chloride. The suppliers were grarteful as they didn't have the facilities to analyse this particular batch.:)

I always had issues in the past when ordering indicators solutions already pre-made. Ever since making my own solutions from the solids, never had any problems and the colours also tend to be clearer and sharper.
 
I always had issues in the past when ordering indicators solutions already pre-made. Ever since making my own solutions from the solids, never had any problems and the colours also tend to be clearer and sharper.
Yes Emil I agree which is why we make them up ourselves. I would urge people not to have complete faith what is marked on the label until you're quite sure exactly what it is.:D
 

Peter Sigsworth

COMMITTEE
Yes Emil I agree which is why we make them up ourselves. I would urge people not to have complete faith what is marked on the label until you're quite sure exactly what it is.:D
That is really worrying - we can't rely on the suppliers sending the correct stuff correctly labelled - there must be a serious H&S issue as one day someone will get injured by such mistakes. Do we have a professional body we can report to? So they can monitor which suppliers are reliable and which not!
 

Peter Sigsworth

COMMITTEE
That is really worrying - we can't rely on the suppliers sending the correct stuff correctly labelled - there must be a serious H&S issue as one day someone will get injured by such mistakes. Do we have a professional body we can report to? So they can monitor which suppliers are reliable and which not!
Or is this issue common to all suppliers?
 
That is really worrying - we can't rely on the suppliers sending the correct stuff correctly labelled - there must be a serious H&S issue as one day someone will get injured by such mistakes. Do we have a professional body we can report to? So they can monitor which suppliers are reliable and which not!

I believe CLEAPSS follows up with such issues if you contact them.
 

Peter Sigsworth

COMMITTEE
I'm just wondering if we, as a group, should set a thread/group to post such issues so we can get a handle on the regular culprits/offenders.
 

Peter Sigsworth

COMMITTEE
they buy it from a 3rd party sometimes.
That's why I have gone back to my supplier in the first instance. I guess the ones who make the most mistakes are the ones who source stuff from the cheapest provider regardless and don't check it before dispatching to their customers.
 

Peter Sigsworth

COMMITTEE
Digging about in store room came across this from same supplier - exp date April 2018
upload_2020-2-25_13-59-19.png
Just blew into it with a straw and got this
upload_2020-2-25_14-0-28.png
Obviously gets better with age!!!!!! and especially after expiry date
 

Peter Sigsworth

COMMITTEE
SciChem changed their supplier last year because of this issue - shame they didn't trace all their customers who bought the faulty batch and tell them.
 
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