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Submission Date
2016-07-28 16:42:40
Name
Melissa Phillips
Organization
NIST
Title of Method
Analysis of Theanine in Tea (Camellia sinensis) Dietary Ingredients and Supplements
by High- Performance Liquid Chromatography with Post-Column Derivatization: Single
Laboratory Validation
AOAC Candidate Method
Number (e.g. ALN-01)
TEA-01
Applicable SMPR
2015.014
Summary:
This method is presented for determination of theanine in green tea containing dietary
ingredients and supplements. The method utilizes simple sonication extraction in
LiCitrate buffer and cation exchange chromatography with post-column ninhydrin
derivatization before absorbance detection.
Tested products include powders, liquids, tablets, capsules, softgels, and gelcaps.
Method did not address gummies or chewables.
1. Does the applicability of
the method support the
applicability of the SMPR? If
not, please explain what is
missing.
The method only addresses the determination of theanine. Method does not address
determination of catechins, methyl xanthines, or theaflavins.
2. Does the analytical
technique(s) used in the
method meet the SMPR? If
not, please specify how it
differs from what is stated in
the SMPR.
Considering only theanine: Analytical range stated in SMPR: 10-100,000 ppm. Lowest
calibration level in method was 0.5 ug/mL or ~500 ppm. Lowest product tested was 41
ppm. Method states to use 0.1 to 1.0 g portions of sample (does this cover the range of
samples concentrations specified in the SMPR?). LOQ stated in SMPR: <5 ppm. LOQ
calculated in method: 3 ppm. Recovery stated in SMPR was met for all conditions
(considering only total recovery). If marginal recovery is considered, method is outside
spec for liquid product (109% at 575 ppm). 80-110% for 10-50 ppm 90-107% for 51-
500 ppm 95-105% for 501-10,000 ppm RSDr stated in SMPR was met for all
conditions. <7% for 10-50 ppm <5% for 51-10,000 ppm Tested products include
powders, liquids, tablets, capsules, softgels, and gelcaps. Method did not address
gummies or chewables.
3. Are the definitions
specified in the SMPR used
and applied appropriately in
the method? If no, please
indicate how the terms are
used.
Yes.
4. Does the method, as
written, contain all
appropriate precautions and
warnings related to the
method's reagents,
components, instrumentation,
or method steps that may be
hazardous? If no, please
suggest wording or option(s).
Yes, very clear section on safety included.
AOAC SPDS ERP - Set 3 Review Form 2