On Wed, 21 Jun 2000 16:24:40 -0600 TWong@biomira.com (Ting Wong) wrote:
>To all those AAA experts out there:
>
>I am trying to run the AAA (amino acid analysis) using the Waters'
>AccQTag method on the HP1100 HPLC system according to a paper Liu et al.
>in Journal of AOAC international, 78 (1995). Unfortunately, the Asp and
>the Glu peaks are eluting with a shoulder and tend to split into two
>peaks. Anybody know how to fix that?
>
>Thanks in advance.
>
>Ting Wong
Hi Ting,
I have been running the AccQ-Tag method for years on an HP1090. I initially
encountered the same problem with split Asp peaks, and discovered, as Len
Packman did, that the splitting of peaks was dependent on the sample volume
injected. Optimum sensitivity is very important to me. My solution was to
decrease the total reaction volume from 100 ul to 20 ul and to inject 8 ul onto
the column. My samples are hydrolyzed by gas phase hydrolysis in 100 ul
hydrolysis vials. Following hydrolysis, the samples are redissolved in 5 ul 20
mM HCl, then 15 ul borate buffer and 5 ul AQC solution is added. Injection
volumes of 5 and 8 ul produced lovely chromatograms, but an injection of 10 ul
produced split Asp peaks.
Kathy Schegg
University of Nevada, Reno
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