ISO 18447:2021 PDF

Name: ISO 18447:2021 — Tea — Determination of theaflavins in black tea — Method using high performance liquid chromatography
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Tea — Determination of theaflavins in black tea — Method using high performance liquid chromatography

Название (английский):

ISO 18447:2021

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

Статус документа:: Действующий
Формат:: Электронный (PDF)
Количество страниц:: 19
Дата публикации:: 10 июня 2021 г.
Издание:: ISO IS 18447 edition 1 version 1
ICS:: 67.140.10

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Описание (английский):

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.

Abstract

Похожие стандарты

Стандарты, упомянутые в описании

Overview

ISO 18447:2021 - Tea - Determination of theaflavins in black tea - Method using high performance liquid chromatography defines a validated HPLC/UHPLC procedure for quantifying the four major theaflavins in tea. The standard applies to leaf and instant black and oolong teas (not validated for ready-to-drink/RTD beverages) and specifies extraction, chromatographic conditions, calibration approaches and reporting requirements for reproducible theaflavin analysis.

Keywords: ISO 18447:2021, theaflavins, black tea, HPLC, UHPLC, tea analysis, tea quality, chromatographic method

Key topics and technical requirements

Analytes covered: the four major theaflavins - TF, TF‑3‑gallate, TF‑3′‑gallate and TF‑3,3′‑digallate.

Method type: Reversed‑phase HPLC or UHPLC with isocratic elution and UV detection (primary wavelength 274 nm; 375 nm optional).

Sample scope: Finely ground leaf tea and instant tea (leaf extraction and instant tea dissolution procedures described). Not validated for RTD beverages.

Extraction and stabilization: Leaf extraction with 70% methanol at 70 °C; instant tea dissolved in hot water with acetonitrile stabilizer. Antioxidants/chelators (ascorbic acid, EDTA) used to stabilize extracts.

Calibration: External theaflavin standards of known purity and moisture content are preferred. Alternatively, a caffeine external standard may be used together with consensus relative response factors (RRFs) established through ISO interlaboratory testing.

Reagents and mobile phases: HPLC-grade methanol, acetonitrile, acetic acid, water (ISO 3696 grade) and stabilizer solutions specified. Mobile phases include acidified aqueous and acetonitrile phases (2% acetic acid).

Quality and precision: The standard includes interlaboratory test results, repeatability and reproducibility guidance, and requirements for test reporting.

Practical applications

Quality control and specification testing for black and oolong tea producers and packers.

Product development and process optimization to monitor fermentation and oxidation (theaflavin formation).

Research laboratories studying tea chemistry, health-related components or processing effects.

Regulatory and certification bodies requiring traceable, standardized quantitation of theaflavins for labeling, trade or conformity assessment.

Related standards

ISO 1572 - Preparation of ground sample of known dry matter content (tea)

ISO 3696 - Water for analytical laboratory use - Specification and test methods

ISO 7513 - Instant tea - Determination of moisture content

This ISO method provides a standardized, reproducible HPLC/UHPLC workflow for accurate theaflavin quantitation - a key metric in assessing black/oolong tea quality and processing outcomes.

ISO 18447:2021 PDF

Abstract

Похожие стандарты

Overview

Key topics and technical requirements

Practical applications

Who should use this standard

Related standards

Технические детали

SIST EN ISO 3696:1998

Water for analytical laboratory use - Specification and test methods (ISO 3696:1987)

BS ISO 157:2025

Coal. Determination of forms of sulfur.

ISO 7513:1990/Amd 1:2012

Instant tea in solid form — Determination of moisture content (loss in mass at 103 degrees C) — Amendment 1