DRAFT Tea SMPR
46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78
Limit of Quantitation (LOQ):
The minimum analyte concentration for which quantitative results may be obtained with 95%
confidence.
Methyl xanthines
Caffeine; theobromine; and theophylline. Refer to table 4 for IUPAC nomenclature and CAS
registry numbers. See figure 2 for chemical structures.
Repeatability:
Variation arising when all efforts are made to keep conditions constant by using the same instrument and operator, and repeating during a short time period. Expressed as the
repeatability standard deviation (SD r
), or % repeatability relative standard deviation (%RSD r ).
Reproducibility:
The standard deviation or relative standard deviation calculated from among-laboratory data.
Expressed as the reproducibility relative standard deviation (SD R
) or %reproducibility relative
standard deviation (%RSD R ).
Recovery:
The fraction or percentage of the analyte that is recovered when the test sample is analyzed
using the entire method.
Theaflavins
Theaflavin, theaflavin-3-gallate, theaflavin-3'-gallate, and theaflavin-3-3'-digallate. Refer to table 6 for IUPAC nomenclature and CAS registry numbers. See figure 3 for chemical
structures.
Theanine
N-ethyl-L-glutamine; (2S)-2-ammonio-5-(ethylamino)-5-oxopentanoate. CAS registry
number: 3081-61-6. See figure 4 for chemical structure.
4. Method Performance Requirements : Table 1: Analytical Ranges and LOQs
Component
catechins
methyl xanthenes
theaflavins
theanine
Analytical range (ppm)
10 – 500,000
10 – 500,000
10 – 100,000
10 – 100,000
LOQ (ppm)
5
79 80
Table 2: Method Performance Requirements by Range
Ranges (ppm)
10 – 50
51 - 500
501– 4,000
4,001 – 20,000
>20,000
Recovery (%)
80 -110
90-107
95-105
97-103
98-102
RSD r
(%)
≤ 7
5
4
2
2
RSD R
(%)
≤ 10
8
6
3
3
81 82 83 84
2
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