Rachel,

I assume you are doing physiological aminoacids.
I assume with each new bottle of ninhydrin or Trione you do a recalibration
of the standard aminoacids material.

What we typically, do is start a new bottle of ninhydrin or Trione and
first run 2 standard, if the 2nd standard is greater then 5% variation from
the previous calibration, we recalibrate. Since, we typically get 44 full
runs on a bottle, we check another standard at about run 20-24 and finally
at the end of the bottle. We don't allow for more then 5% decay over the
time the bottle is on the machine. If this occurs, I believe the nin is bad
and call the manufacturer.

As for QC, you have 2 choices:
1. Mix up a bunch of left over plasma to make a container of pooled plasma
or contact the Blood Bank or ICU at you hospital. The bank may have
some  outdated plasma bags or the ICU may have a partly used back from a
expired patient. I suggest you take the pooled plasma from either source,
deproteinize it with the internal standard , spin, filter, aliquot and
freeze...the colder the better. If stored at -80, you will see very little
change over time. Most, noticeable maybe a decrease in glutamine or
trytophan. If the ammonia is rising, the glutamic acid is rising and the
glutamine is falling, then it is decaying.  I have used this material for
15 months with high confidence.

One other note, for this QC material, if you want you can pick any or a
couple aminoacids and add pure L-aminoacid to it. i.e., your QC shows about
60 phenylalanine, add another 100-150 to the plasma to raise the level.
This peak occurs very clean and yours QC results should be very consistent.

If you can take some of your QC material and send it around to some
colleagues to test, it will give all involved a sense of variability of the
assay and the "Central Hospital Inspection Commissions" ours is CLIA like
this inter institutional data.

any further questions, just drop a note

best regards
prof frank
President and Laboratory Director
Scientific Research Consortium, Inc..
St. Paul, MN, USA
http://www.aminoacids.com

Clinical Associate Professor
College of Pharmacy
University of Minnesota



At 06:47 PM 12/12/2000 +0000, you wrote:



>>What do you use as quality control for the Biochrom amino acid analyser?
>>- (rather than an internal standard) to check that you are performing
>>accurately?
>
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