6.2-3
Section 6
ApplicAtions
Pinnacle Operators Manual
Pickering Laboratories Inc.
The early-eluting amino acids — taurine, urea, aspartic acid, threonine, serine, etc. — are particularly
sensitive to pH and normality. Accordingly the samples must be held to a narrow pH range between 2.1 and
2.5, and the proper lithium ion concentration to ensure reproducibility in the early part of the chromatogram.
The later-eluting compounds are more tolerant of initial sample conditions, and their retention times are not
as likely to be affected. SERAPREP
™
and URIPREP
™
replace commonly-used protein precipitation reagents such
as acetonitrile, perchloric acid and picric acid, and eliminate the need for dialysis, ultrafiltration, and repeated
centrifugation steps, followed by pH adjustment.
• Filter all samples through a 0.45µm membrane filter. Some samples may require even more stringent
filtration, especially if colloids are present.
• Samples must always be properly buffered. The ideal pH for sample injection is pH 2.3 ± 0.2.
• For native samples, be sure that all proteins have been removed before analysis.
PHYSIOLOGIC FLUID SAMPLES:
PREPARATION USING SERAPREP
™
OR URIPREP
™
Use SERAPREP
™
for preparing serum and other samples with a high buffering capacity, e.g. sardine oil. Use
URIPREP
™
for preparing urine and other samples with low buffering capacity, such as fruit juices, musts and
warts. The efficiency of protein precipitation and the need for post-centrifugation pH adjustment of the sample
determine which reagent is best for your particular sample.
1. In a microcentrifuge tube thoroughly mix equal portions of sample and SERAPREP
™
or URIPREP
™
.
2. Let stand for 5 minutes. Centrifuge the mixture at 13,000 rpm for 5 minutes. Check the supernate pH to
ensure that the range is pH 2.3±0.2. Adjust the initial mixing ratio as necessary.
3. Filter the supernate with a syringe filter (0.2 or 0.45 um).The filtrate is ready to be injected into an auto-
sampler vial for amino acid analysis.
4. If further dilution is needed, use Li 220 to adjust the concentration of analyte.
Reagent Preparation
TRIONE PREPARATION
TRIONE
®
reagent requires little to no preparation, depending on what type you use.
T100: The one-part TRIONE
®
(Cat. No. T100C) requires no preparation - simply pour the TRIONE
®
directly
into the reagent reservoir and put the cap on the reservoir.
T200: To prepare two-part TRIONE
®
(Cat. No. T200), pour Bottle 1 into the reservoir, add Bottle 2 to the
reservoir, and cap tightly under Nitrogen. Swirl until homogeneous.
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