GB/T 21729-2008 English PDF

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GB/T 21729-2008: Determination of selenium content in tea
Status: Obsolete

Standard ID	USD	BUY PDF	Lead-Days	Standard Title (Description)	Status
GB/T 21729-2008	219	Add to Cart	2 days	Determination of selenium content in tea	Obsolete

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Basic data

Standard ID: GB/T 21729-2008 (GB/T21729-2008)
Description (Translated English): Determination of selenium content in tea
Sector / Industry: National Standard (Recommended)
Classification of Chinese Standard: X04
Classification of International Standard: 67.140.10
Word Count Estimation: 5,558
Date of Issue: 2008-05-04
Date of Implementation: 2008-10-01
Quoted Standard: GB/T 8302; GB/T 8303
Regulation (derived from): National Standard Approval Announcement 2008 No.6 (Total No.119)
Issuing agency(ies): General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China, Standardization Administration of the People's Republic of China
Summary: This standard specifies the method of detection by atomic fluorescence spectrometry selenium content of tea. This standard applies to the determination of selenium in tea.

GB/T 21729-2008: Determination of selenium content in tea

---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order.
Determination of selenium content in tea ICS 67.140.10 X04 National Standards of People's Republic of China Detection of selenium in tea Posted 2008-05-04 2008-10-01 implementation Administration of Quality Supervision, Inspection and Quarantine of People's Republic of China Standardization Administration of China released

Foreword

This standard is proposed and managed by China Federation of Supply and Marketing Cooperatives. This standard was drafted. China Federation of Supply and Marketing Cooperatives Hangzhou Tea Research Institute. The main drafters of this standard. Zhou Weilong, Xu Jianfeng, Sha Tao, Xu Ling. Detection of selenium in tea

1 Scope

This standard specifies the method for detection by atomic fluorescence spectrometry of selenium in tea. This standard applies to the determination of selenium in tea.

2 Normative references

The following documents contain provisions which, through reference in this standard and become the standard terms. For dated references, subsequent Amendments (not including errata content) or revisions do not apply to this standard, however, encourage the parties to the agreement are based on research Whether the latest versions of these documents. For undated reference documents, the latest versions apply to this standard. GB/T 8302 sampling tea Sample Preparation and Determination of dry matter content GB/T 8303 Tea grated Principle 3 Heated tea samples after acid digestion, at 6mol/L HCl medium, the reduction of hexavalent selenium in the sample into tetravalent selenium, potassium borohydride As the reducing agent, the reduction of tetravalent selenium in the medium of hydrochloric acid into hydrogen selenide by the carrier gas into the atomizer in atomic technology, selenium hollow female Extremely light irradiation, a selenium atom ground state are excited to high energy states in the deactivated to the ground state, emit a characteristic fluorescence wavelength, and the fluorescence intensity Proportional to the selenium content, compared with standard series quantitation.

4 Instrument

4.1 atomic fluorescence spectrometer. 4.2 selenium hollow cathode lamp. 4.3 Electric hot plate. 4.4 commonly used laboratory equipment.

5 Reagents

The standard water is deionized water, unless otherwise specified, the reagents were of analytical grade. 5.1 nitric acid (HNO3). pure class distinctions. 5.2 perchloric acid (HClO4). pure class distinctions. 5.3 HNO3 + HClO4 mixed acid (by volume). 4 +1. 5.4 hydrochloric acid (HCl). pure class distinctions. 5.5 hydrochloric acid (6mol/L). hydrochloric acid (5.4) with the volume of water and mix. 5.6 potassium hydroxide. 5.7 potassium borohydride. 5.8 solution of potassium borohydride (8g/L). Weigh 8.0g potassium borohydride (5.7), was dissolved in a solution of potassium hydroxide (5g/L) and constant volume 1000mL, shake. 5.9 ferricyanide solution. 100g/L. 5.10 selenium standard solution 5.10.1 selenium standard solution. 100μg/mL. 5.10.2 selenium standard working solution Ⅰ (10μg/mL). Pipette 100μg/mL of selenium standard solution (5.10.1) 1.0mL, water volume to 10mL, shake. ......

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