At 09:59 PM 5/15/99 -0500, Debora Fontanini wrote:
>..........................
>I am analyzing the activity of an enzyme in the process of being purified,
>using an HPLC assays; the reaction products are analyzed by separation on a
>Zorbax C-18 column, using the following gradient: 0.1% TFA (A) in water
>with 20% of 0.1% TFA (B) in acetonitrile, going up to 50% in 14 minutes.
>The substrate and the products elutes at about 35% of B.
>To accurately quantify the amount of digestion, in presence and without a
>particular inhibitor, I need to use an internal standard..............
>Can any of you think of something that I could use in my reaction and
>inject as a standard, which possibly elutes before my substrate (I would
>like not to use a longer gradient, if avoidable) and absorbs nicely at 254nm?
>
>Any help is greatly appreciated,
>
>
>Debora Fontanini-Sella
>University of Wisconsin-Madison
>e-mail: dfontani@facstaff.wisc.edu
>phone: (608) 262-4478
>
John Hempel, PhD Ph (412) 624 0161
University of Pittsburgh FAX (412) 624 4759
Department of Biological Sciences
Pittsburgh PA 15260 email: hempel@psc.edu
http://www.pitt.edu/~biology/faculty/hempel.html