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BS ISO 18447:2021

BS ISO 18447:2021

$142.49

Tea. Determination of theaflavins in black tea. Method using high performance liquid chromatography

Published By Publication Date Number of Pages
BSI 2021 26
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This document specifies a high performance liquid chromatography (HPLC) or ultra-high performance liquid chromatography (UHPLC) method for the determination of content of the four major theaflavins of tea.

It is applicable to both leaf and instant black and oolong teas. The method is currently not validated for ready-to-drink (RTD) beverages.

PDF Catalog

PDF Pages PDF Title
2 National foreword
6 Foreword
7 1 Scope
2 Normative references
3 Terms and definitions
4 Principle
5 Reagents
5.1 General
8 5.1.8 20 % acetonitrile stabilizer solution.
5.1.9 Leaf/infusion stabilizing solution.
5.2 HPLC mobile phases
5.3 Stock standard solutions
5.3.1 General
9 5.3.2 Preparation of individual theaflavin stock standard solutions
5.4 Mixed standard solutions
5.5 Caffeine standard — Preparation of caffeine stock solution, corresponding to 2,00 mg/ml
10 6 Apparatus
11 6.12 Data collection/integration system.
7 Sampling
8 Preparation of test samples
9 Procedure
9.1 General
9.2 Determination of dry matter content
12 9.3 Test portion
9.3.1 Instant tea
9.3.2 Leaf tea
9.4 Extraction of theaflavins
9.4.1 Instant tea
9.4.2 Leaf tea
9.5 Dilution
13 9.6 Determination
9.6.1 General
9.6.2 Adjustment of the apparatus
9.6.3 HPLC analysis
9.6.4 Identification
14 10 Calculation
10.1 General
10.2 Quantitation using theaflavin standards
15 10.3 Quantitation using a caffeine standard and theaflavin RRFs
16 11 Precision
11.1 Interlaboratory test
11.2 Repeatability
11.3 Reproducibility
12 Test report
17 Annex A (informative) Results of interlaboratory tests
18 Annex B (informative) Assessment of the purity of standards used in the RRF work
19 Annex C (informative) Typical HPLC chromatograms
24 Bibliography

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BS ISO 18447:2021
$142.49