Re: AAA-GLP

Sandy Kielland (kielland@UVic.CA)
Fri, 28 Aug 1998 12:35:22 -0700

Hello to all;
I guess that I am just an old dinosaur, but I have used a very low tech
(and cheap) hydrolysis method for ten years and I'm very happy with it.
Over the years I have tried many "improvements" but have always gone back.
I use the method suggested in the origional ABI bulletin gas phase
hydrolysis method. My hydrolysis blanks are squeaky clean (well, maybe a
few pmole glycine) and I get good results with low picomole level samples,
so my customers tell me. I have quite a low throughput in my lab...I rarely
have more than ten samples to run in a week...but the method is so easy
that I can't imagine it would be a problem for people with more samples.
The caps for the 50 ml heavy walled centrifuge tubes are critical, as
others have noted. Many years ago I tried mininert type valves but had
quite a few problems, so I disassembled them and used the outer screw-on
part, inserting a new "Tuf-bond" teflon+silicon disc for each batch. In my
hands, evacuating the hydrolysis vessel was not a good idea anyway because
it tended to lower the concentration of HCl.
I for one would be interested in the AAA evaluation you speak of. Interest
in this ancient technique is dwindling but perhaps that trend can be
reversed. I believe that AAA numbers are very valuable.

Sandy Kielland
Department of Biochemistry and Microbiology
University of Victoria
Victoria, B.C. Canada

At 02:42 PM 27/08/98 -0500, Ritter,Nadine wrote:
>What superb ideas from everyone! Thanks to all who have given us suggestions
>for improvements in our hydrolysis woes, and maybe even saved us some big
>bucks to boot.
>
>The question I now have is this: If the Pico-Tag workstation is no longer
>going to be available, what alternatives are there for convenient hydrolysis
>methods, and how do they compare to the PicoTag system? I recall some
>discussion a long while back on microwave units, but what about other methods
>of hydrolysis? In reviewing the past ABRF AAA studies, two addressed
>hydrolysis: in 1989, the ABRF study showed that hydrolysis was a highly
>variable step in amino acid analysis, but it did not focus on the relative
>merits of different hydrolysis methods. The 1994 study confirmed that good
>hydrolysis is critical in obtaining accurate AA results, regardless of the
>derivatization method or instrument used. Of course, hydrolysis has been an
>internal part of the AAA Research Committee studies all along, but as far as
>I can tell, it has never been singled out for comparative evaluation.
>
>Might we consider a study on different hydrolysis systems? Is this even a
>do-able study? Do other ABRF'rs have an interest in this issue? Or is
>everyone happy with their current system, with no need to replace the
>instrument or method they use? How many out there do high-throughput AAA
>where instrument viability, performance degradation, and future availability
>of new equipment are causes for concern?
>
>My overriding query: In the shrinking world of AAA technology, as is evident
>by the loss of instrumentation options for this analytical method and the
>lack of new technical developments, is it time to re-evaluate what options
>are left to those of us who continue to do AAA? I know it isn't the most
>glamorous analytical method anymore, but it is quite an important quality
>assurance test for biological products.
>
>I'd like to hear your views (and I know I will!).
>
>Thanks
>
>Nadine Ritter
>Abbott Diagnostics Division
>Nadine.Ritter@add.ssw.abbott.com
>
>
>