GB/T 7472-1987Water quality--Determination of zinc--Spectrophotometric method with dithizone (English PDF)

3 Principle

4 Reagents

5 Apparatus

6 Sampling and samples

7 Procedure

8 Expression of the results

9 Precision and accuracy

Foreword

This document was issued on 6 March 1987 by the State Administration for Market Regulation and the Standardization Administration of the People's Republic of China, and has been in force since 1 August 1987.

It is the first edition of this standard.

Classification: ICS 13.060, CCS Z16.

About this edition

GB/T 7472-1987 is the first edition of this standard. It was issued on 6 March 1987 and has been in force since 1 August 1987.

There is no earlier edition to compare it with, so a specification that has to refer to this subject can only cite GB/T 7472-1987 itself.

The interval between issue and effect is the transition period. It exists so that producers, laboratories and buyers can requalify products, revise procedures and use up documentation before the new text becomes the one that applies. The date on this page is the official one from the record of the Standardization Administration.

Edition history and citation

GB/T 7472-1987 is a first edition: there is no earlier version of this standard, so a document that needs to refer to this subject can only cite GB/T 7472-1987 itself.

Where an edition is replaced, the Chinese standardization system keeps the number and changes the year: the number identifies the subject, the year identifies the text. That is why a citation without a year is ambiguous and a citation with one is not.

Classification and status

GB/T 7472-1987 is classified under ICS 13.060, in the field of environment and health protection, safety. ICS is the International Classification for Standards, the same scheme used by ISO and by the national bodies of most countries, which is what allows a Chinese standard to be placed beside its foreign counterparts on subject rather than on number.

Its Chinese Standard Classification code is CCS Z16. CCS is the domestic scheme, a letter for the sector and two digits for the subject within it, and it is the code by which the standard is filed and searched in China.

The GB/T prefix marks a recommended national standard. It is not, in itself, law: it becomes binding when a contract names it, when a regulation or a mandatory standard refers to it, or when a producer declares conformity with it. In practice that covers most of the cases in which it will be read — a purchase specification, an inspection agreement or a certification scheme.

How this standard is designated

The full designation is GB/T 7472-1987. A citation should carry the number with its year, because the year identifies the text that applies.

In a catalogue or a filing system it is found under ICS 13.060 and CCS Z16 — the international classification and the Chinese one, which are the two codes by which a standard on this subject is searched.