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Science Forum Index » Chemistry Forum » what is dependence of pH or dissociation constant and...
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| bubu... |
 Posted: Fri May 30, 2008 4:25 am |
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The question is like in subject.
I will be very happy if somebody help me.
I am doing separations of amino acids by HPLC with acetate bufer/ACN and
i have a problem when temperature i changing. |
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| Bill Penrose... |
| Posted: Fri May 30, 2008 4:49 am |
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On May 30, 6:25 am, bubu <z... at (no spam) o2.pl> wrote:
Quote: The question is like in subject.
I will be very happy if somebody help me.
I am doing separations of amino acids by HPLC with acetate bufer/ACN and
i have a problem when temperature i changing.
There are too many temperature coefficients at work here to be
certain.
To my recollection, the pH of acetate buffer decreases with increasing
temperature, but in mixture with AcCN, who knows? Also, the pH
electrode and counter electrodes each have their own coefficients.
Also, the behavior of your analyte amino acids will also change. The
solution is to keep the temperature as constant as possible and not
try to correct for changes.
Dangerous Bill |
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| Bob... |
| Posted: Fri May 30, 2008 8:43 pm |
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On Fri, 30 May 2008 07:49:48 -0700 (PDT), Bill Penrose
<penrose at (no spam) iit.edu> wrote:
Quote: On May 30, 6:25 am, bubu <z... at (no spam) o2.pl> wrote:
The question is like in subject.
I will be very happy if somebody help me.
I am doing separations of amino acids by HPLC with acetate bufer/ACN and
i have a problem when temperature i changing.
There are too many temperature coefficients at work here to be
certain.
To my recollection, the pH of acetate buffer decreases with increasing
temperature, but in mixture with AcCN, who knows? Also, the pH
electrode and counter electrodes each have their own coefficients.
Also, the behavior of your analyte amino acids will also change.
My memory says that is likely to be the largest effect. As a
generality, amines have rather large changes of K with temperature.
More importantly, various k will change differently. The separation
depends on T.
Quote: The
solution is to keep the temperature as constant as possible and not
try to correct for changes.
Agreed!
bob |
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