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Sugar solution had changed colour


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8 replies to this topic

#1 Adrian K

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Posted 12 November 2009 - 06:36 PM

I had prepared 1M D-galactose and 1M D-mannose solutions few months ago. However it seems to turn "orange".
although I haven't plate it yet to determine contamination, but from the solution itself it is clear and no cloudy effect.

My question is:

1) is this normal?
2) can the solution still be use to elute proteins?
3) what is the possible reason for it to turn "orange"

Thank you.

P/s: I'm sorry cos i not a biochemistry background.
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#2 Prep!

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Posted 12 November 2009 - 11:17 PM

i ve heard of glucose and galactose browning at higher temperatures when present with a glycine system... but not sure if this color change is normal... normally sugars wil chnge color only on addition of certain reagents (benedicts the most common)
this may not be any growth but accidental addition of some reagent.. acid.. base... watever... so i wud say its better not to use it for any further experimentation unless confirmed!!!
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#3 gogreen

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Posted 13 November 2009 - 12:06 AM

Agree with PI, never heard of sugar solns turning color by itself!! But upon heating, sugar solutions turn brown

" 2) can the solution still be use to elute proteins? "
Golden rule - Its always better to prepare the reagents afresh in case if you have the slightest doubt about it. That would save you quite a long time in long run :P

#4 mdfenko

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Posted 13 November 2009 - 11:08 AM

how was the solution stored?

the orange color can be due to caramelization of the sugar (requires heat, maybe sunlight caused it).

if there is an amino acid (eg glycine) in the solution then the sugar may have undergone the maillard reaction.
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#5 Adrian K

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Posted 15 November 2009 - 05:52 PM

I store the solution in clear blue cap bottles at open lab benches. Maybe the bottles were being used to prepare agar media before and wasn't well clean. However, both caramelization and mailard reaction requires some heat. From what I understood, both process will not happen in a very slooowww process or motion.

It sounds like somebody in my lab try to sabotage my work...
:angry: :( :) :blink: :huh:
Expecting the world to treat you fairly because you are a good person is like expecting the lion not to attack you because you are a vegetarian.

..."best of our knowledge, as far as we know this had never been reported before, though I can't possible read all the published journals on earth, but by perform thorough search in google, the keywords did not match any documents"...

"what doesn't kill you, makes you stronger"---Goddess Casandra reminds me to be strong

"It's all just DNA. Do it."---phage434

#6 Prep!

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Posted 15 November 2009 - 09:37 PM

ya so the best option in any case it re prepare and use!!! :D
and don keep ur stocks for too long for ur fellaws to fiddle wid it!!! :D
seems tat u doin fast research... they might just want u to be at the same pace.. sooo... :lol: :lol: :lol:
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#7 Minni

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Posted 16 November 2009 - 08:05 PM

was the clear blue cap container glass or plastic? was it clean and fresh i.e a new one? First sort out all these problems before you blame your collegues... May be the cleaning agent used for cleaning the conatiner left some residues which caused the colour change..
Anyway for success in regular lab work is to preparae small quantities of solutions and prepared fresh as much as possible..
Dont worry it may not be an act of sabotage or something.. just throw it make frash solutions and start your work..

I store the solution in clear blue cap bottles at open lab benches. Maybe the bottles were being used to prepare agar media before and wasn't well clean. However, both caramelization and mailard reaction requires some heat. From what I understood, both process will not happen in a very slooowww process or motion.

It sounds like somebody in my lab try to sabotage my work...
:D :( :P ;) :huh:



#8 Adrian K

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Posted 17 November 2009 - 06:33 PM

Thank You Minni,
The cap is plastic, although is not a new one, but we do clean it with standard procedure from detergent washing, autoclaving and oven baking. I had recently tested with our detergent and it doesn't seems to be the case.
Anyway, it doesn't matter anymore because I had prepared new solutions.

Thank you all for your comments and enlightenment. :)
Expecting the world to treat you fairly because you are a good person is like expecting the lion not to attack you because you are a vegetarian.

..."best of our knowledge, as far as we know this had never been reported before, though I can't possible read all the published journals on earth, but by perform thorough search in google, the keywords did not match any documents"...

"what doesn't kill you, makes you stronger"---Goddess Casandra reminds me to be strong

"It's all just DNA. Do it."---phage434

#9 mdfenko

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Posted 18 November 2009 - 01:11 PM

I store the solution in clear blue cap bottles at open lab benches. Maybe the bottles were being used to prepare agar media before and wasn't well clean. However, both caramelization and mailard reaction requires some heat. From what I understood, both process will not happen in a very slooowww process or motion.

if the bottles are exposed to sunlight then they may be getting enough energy to drive the reactions.

do your caps have liners? if so, then you may be dissolving glue into your solutions (this has happened to us).
talent does what it can
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