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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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