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2. Does the method contain
system suitability tests or
controls as specified by the
SMPR? If not, please indicate
if there is a need for such
tests or controls and which
ones.
Yes. A blank check sample could be added to comply with SMPR.
3. Is there information
demonstrating that the
method system suitability
tests and controls as
specified in the SMPR worked
appropriately and as
expected? If no, please
specify.
Yes.
4. Based on the supporting
information, is the method
written clearly and concisely?
If no, please specify the
needed revisions.
Yes. I would add more guidance under the section for sample preparation to assist in
choice of sample size and extraction volume. Something like "Choose sample size
corresponding to approximately X mg of catechins/analytes".
5. Based on the supporting
information, what are the
pros/strengths of the
method?
The method is simple and straightforward (sonication extraction, chromatography,
detection). This method could be easily implemented in any laboratory.
The chromatography is fast and appears to separate the 8 compounds of interest.
6. Based on the supporting
information, what are the
cons/weaknesses of the
method?
The method has not demonstrated accuracy via use of reference materials or
spike/recovery studies. The method may benefit from inclusion of an internal standard.
The method has not demonstrated adequate precision as specified in the SMPR.
The method has not demonstrated adequate linearity, LOQ, and LOD as stated in the
SMPR.
Unknown how method would respond to additional matrices specified in the SMPR,
particularly gummies/chewables (2 difficult matrices). Sonication extraction might not
be sufficient.
7. Any general comments
about the method?
This is a good start, but even for the limited number of compounds and matrices
included, most of the SMPR requirements are not met. A significant amount of work is
needed before this method will meet the SMPR.
Do you recommend this
method be adopted as a First
Action and published in the
Official Methods of Analysis
of AOAC INTERNATIONAL?
Please specify rationale.
At this time, I do not recommend this method for first action status. Additional work is
needed to include more matrices (and possibly more analytes), and to improve the
separation and/or extraction to address the high recovery values. Inclusion of an
internal standard may help. If someone is willing to take this on, the method seems to
be a good place to start.