According to Qiagen
> Since imidazole absorbs UV radiation at 280 nm, an elution profile
> measured at 280 nm while purifying a 6xHis tagged protein by FPLC will
> show an increase in absorbance above the background signal allowing
> quantitation of your protein. The absorbance of imidazole can vary
> depending on its source and purity, but elution buffer containing 250
> mM imidazole usually has an A280 of 0.2–0.4.
Cheers,
Ed.
On Wed, 2013-08-21 at 11:25 -0400, Edward A. Berry wrote:
> Would you happen to know what the A280 of a 1M (or .1 M) solution is?
> I wonder if this absorbance is really due to impurities or is the tail of a weak absorbance band of imidazole itself. I
> notice A280 is not one of the properties sigma lists for its imidazole.
>
> Jan 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
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--
Edwin Pozharski, PhD, Assistant Professor
University of Maryland, Baltimore
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