GB/T 9741-2008 English PDF (GBT9741-2008)

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GB/T 9741-2008: Chemical reagent -- General method for the determination of residue after ignition
GB/T 9741-2008
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 71.040.30
G 60
Replacing GB/T 9741-1988
Chemical reagent -- General method for the determination
of residue after ignition
(ISO 6353-1:1982, Reagents for chemical analysis -- Part 1: General test
methods, NEQ)
ISSUED ON: MAY 15, 2008
IMPLEMENTED ON: NOVEMBER 01, 2008
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine of the People's Republic of China;
Standardization Administration of the People's Republic of China.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Method principle ... 4
3 Instruments ... 4
4 Determination ... 4
5 Calculation ... 5
Foreword
The degree of consistency between this Standard and ISO 6353-1:1982 "Reagents for
chemical analysis -- Part 1: General test methods" is not equivalent.
This Standard replaces GB/T 9741-1988 "Chemical reagent -- General method for the
determination of residue after ignition". Compared with GB/T 9741-1988, the main
changes in this Standard are as follows:
- Adjust the ignition temperature (Chapter 1, 3.3 of Edition 1988; Chapter 1, 3.3 of
this Edition);
- Delete Annex A (Edition 1988).
This Standard was proposed by China Petroleum and Chemical Industry Association.
This Standard shall be under the jurisdiction of Subcommittee on Chemical reagents of
National Technical Committee on Chemical of Standardization Administration of China
(SAC/TC 63/SC 3).
The drafting organization of this Standard: Shanghai Shisi Hewei Chemical Co., Ltd.
Main drafter of this Standard: Jia Ling.
This Standard was first issued in 1988.
Chemical reagent -- General method for the determination
of residue after ignition
1 Scope
This Standard specifies a general method for the gravimetric determination of ignition
residue.
This Standard is applicable to the determination of the burning residue of chemical
reagents that can be sublimated or carbonized and can be removed at 650℃±50℃.
When using this standard to measure ignition residue, the mass of the residue calculated
based on the sampling amount and specification value shall not be less than 1 mg.
2 Method principle
Utilizing the differences in physical and chemical properties such as volatility, stability
to heat, and oxygen between the sample body and the substances that form the residue,
the sample is heated at low temperatures to volatilize, carbonize, and burn at high
temperatures to completely separate the sample body from the residue. The mass of the
residue can be weighed using a scale.
3 Instruments
3.1 General laboratory instruments.
3.2 Crucible or evaporating dish: depending on the nature of the sample, the material
can be platinum, quartz or ceramic.
3.3 High temperature furnace: the temperature can be maintained at 650℃±50℃.
3.4 Analytical balance: graduation value is 0.1 mg.
4 Determination
4.1 Precautions for determination
When volatilizing or carbonizing a sample, if the sample size is large, it can be added
in several batches. Add sulfuric acid to the liquid sample. It shall be added all at once
before evaporation or carbonization. If the sample is organic, combustion shall be
avoided.