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1. Are the definitions
specified in the SMPR used
and applied appropriately in
the supporting
documentation (manuscripts,
method studies, etc...)? If not,
please explain the differences
and if the method is impacted
by the difference.
Yes.
2. Is there information
demonstrating that the
method meets the SMPR
Method Performance
Requirements using the
Reference Materials stated in
the SMPR? If not, then
specify what is missing and
how this impacts
demonstration of
performance of the method.
No. 3 NIST SRMs were used for demonstration of accuracy. Values reported in the
method were compared to the values in the COAs from NIST. Values for GC and GCG
were outside of the certified range (high) for all 3 materials. The values for EGCG in
the green tea leaves and for ECG in the green tea extract were also high. This
indicates a likely interference in the chromatography with GC and GCG, and possibly
with the other components as well.
3. Is there information
demonstrating that the
method performs within the
SMPR Method Performance
Requirements using the
Reference Materials stated in
the SMPR? If not, then
specify what is missing and
how this impacts
demonstration of method
performance.
No. 3 NIST SRMs were used for demonstration of accuracy. Values reported in the
method were compared to the values in the COAs from NIST. Values for GC and GCG
were outside of the certified range (high) for all 3 materials. The values for EGCG in
the green tea leaves and for ECG in the green tea extract were also high. This
indicates a likely interference in the chromatography with GC and GCG, and possibly
with the other components as well.
4. Is there information
demonstrating that the
method performs within the
SMPR Method Performance
REquirements table
specifications for all analytes
in the SMPR applicability
statement? If not, please
specify what is missing and
whether or not the method's
applicability should be
modified.
The method only addresses the determination of 7 catechins and caffeine. The method
does not address the determination of CG, other methyl xanthines, theanine, or
theaflavins.
The method could potentially be extrapolated to include some of the other compounds
(CG, theobromine, theophylline).
1. Based on the supporting
information, were there any
additional steps in the
evaluation of the method that
indicated the need for any
additional precautionary
statements in the method?
No