Hi,
We have experienced similar problems and did some analysis. Here are the
results:
Test of several Imidazole solutions for absorbance at 280 nm. The
solutions have been prepared from the powders purchased from different
suppliers.
* VWR/PROLABO, Cat#24720.157, Batch: 07F180052
* VWR/MERK, Cat# 1.04716.1000, Lot: LO12164316.
* Opened Sigma (cat. I2399-500G, Lot# 050M01771V), in use for about
one year.
* Unopened Sigma (cat. I2399-500G, Lot# 051M00841V. Brand new bottle,
opened just before an experiment.
Here is the data:
Wavelength
2 M Stock solution
(unbuffered in MQ water)
250 mM solution
in MQ water
VWR/PROLABO
260 nm
1.249
0.141
VWR/PROLABO
280 nm
1.628
0.192
VWR/PROLABO
320 nm
1.259
0.139
VWR/MERK
260 nm
0.060
0.010
VWR/MERK
280 nm
0.049
0.002
VWR/MERK
320 nm
0.028
0.002
Opened Sigma
260 nm
1.386
0.158
Opened Sigma
280 nm
1.545
0.178
Opened Sigma
320 nm
0.931
0.104
Unopened Sigma
260 nm
2.277
0.276
Unopened Sigma
280 nm
2.734
0.327
Unopened Sigma
320 nm
1.258
0.147
Hope it would help to other people as well ,
Kostya
--
Konstantin (Kostya) Kogan
Postdoc fellow
Adrian Goldman's Lab
Division of Biochemistry and Biotechnology
Department of Biosciences
Faculty of Biological and Enviromental Sciences
University of Helsinki
Viikinkaari 5D, Room 3036b
POB 56, 00014
Helsinki, Finland
Mobile: +358-(0)45-8994342
Office: +358-(0)9-191-58907
On 22/08/2013 4:03 AM, John Newitt wrote:
> Yes, I think that's the one we use now. I believe it is the current
> branding of the Fluka imidazole that we always ordered. Definitely
> lower UV absorbance. We also prefer Roche high purity DTT for the same
> reason.
>
> John
>
> Sent from my iPad
>
> On Aug 21, 2013, at 11:04 AM, Jan <[log in to unmask]
> <mailto:[log in to unmask]>> wrote:
>
>> Hi Bernhard,
>> this one works for us:
>> Sigma BioUltra imidazole, >99.5% by GC, 56749
>>
>> Cheers,
>> Jan
>> --
>> Jan Abendroth
>> Emerald BioStructures
>> Seattle / Bainbridge Island WA, USA
>> home: Jan.Abendroth_at_gmail.com
>> work: JAbendroth_at_embios.com
>> http://www.emeraldbiostructures.com
>>
>> On Aug 21, 2013, at 7:33 AM, Bernhard Rupp <[log in to unmask]
>> <mailto:[log in to unmask]>> wrote:
>>
>>> Hi Fellows,
>>>
>>> could someone please point me towards the source of a known high
>>> purity imidazole
>>> with low absorbance at 280 nm? I am facing the problem of detecting
>>> a low absorption protein
>>> in high imidazole background after IMAC gradient elution. In the UV
>>> spectra of the
>>> 2 imidazoles I checked there is some contaminant that absorbs at 280…
>>>
>>> Thx, BR
>>>
>>> ----------------------------------------------------------------------------------------
>>> Bernhard Rupp
>>> Marie Curie Incoming International Fellow
>>> Innsbruck Medical University
>>> Schöpfstrasse 41
>>> A 6020 Innsbruck – Austria
>>> +43 (676) 571-0536
>>> [log in to unmask] <mailto:[log in to unmask]>
>>> ----------------------------------------------------------------------------------------
>>> Dept. of Forensic Crystallography
>>> k.-k. Hofkristallamt
>>> Vista, CA 92084
>>> 001 (925) 209-7429
>>> [log in to unmask] <mailto:[log in to unmask]>
>>> [log in to unmask] <mailto:[log in to unmask]>
>>> http://www.ruppweb.org/
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>>>
>>>
>>
