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GB/T 5519-2018 PDF in English


GB/T 5519-2018 (GB/T5519-2018, GBT 5519-2018, GBT5519-2018)
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GB/T 5519-2018: PDF in English (GBT 5519-2018)

GB/T 5519-2018
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 67.060
B 20
Replacing GB/T 5519-2008
Cereals and Pulses - Determination of the Mass of 1,000
Grains
(ISO 520:2010, MOD)
ISSUED ON: FEBRUARY 6, 2018
IMPLEMENTED ON: SEPTEMBER 1, 2018
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 ... 5
2 Normative References ... 5
3 Terms and Definitions ... 5
4 Principle ... 5
5 Instruments and Appliances ... 6
6 Operating Procedures ... 6
7 Result Expression ... 6
8 Precision ... 7
9 Other Instructions on the Determination Process ... 9
Appendix A (informative) Interlaboratory Test Results ... 10
Bibliography ... 14
Cereals and Pulses - Determination of the Mass of 1,000
Grains
1 Scope
This Standard specifies the method for the determination of the mass of 1,000 grains of cereals
and pulses.
This Standard is applicable to all cereals and pulses.
This Standard does not apply to seeds for sowing.
2 Normative References
The following documents are indispensable to the application of this document. In terms of
references with a specified date, only versions with a specified date are applicable to this
document. In terms of references without a specified date, the latest version (including all the
modifications) is applicable to this document.
GB/T 10362 Inspection of Grain and Oils - Determination of Moisture Content of Maize (GB/T
10362-2008, ISO 6540:1980, MOD)
GB/T 21305 Cereals and Cereal Products - Determination of Moisture Content - Routine
Reference Method (GB/T 21305-2007, ISO 712:1998, IDT)
ISO 24557 Pulses - Determination of Moisture Content - Air-oven Method
3 Terms and Definitions
The following terms and definitions are applicable to this document.
3.1 mass of 1,000 grains as received
The mass of 1,000 specimen grains containing natural moisture.
3.2 mass of 1,000 grains on the dry basis
The mass of 1,000 specimen grains after deducting the moisture content.
4 Principle
Weigh and count the complete grains in the specimen, divide the mass of the complete grains
by the number of grains, and express the result as the mass of 1,000 grains.
5 Instruments and Appliances
5.1 Sample splitter (if necessary).
5.2 Grain counter: a photoelectric counter can be used. If there is no suitable counter, it can be
manually counted.
5.3 Balance: with a division value of 0.001 g.
6 Operating Procedures
6.1 Determination of Mass of 1,000 Grains as Received
Randomly take out about 500 specimen grains from the laboratory sample, pick out the
complete grains and weigh them (mt), accurate to 0.01 g; record the number of complete grains
(N).
Each sample shall be tested twice in parallel.
6.2 Determination of Mass of 1,000 Grains on the Dry Basis
After removing impurities in the specimen, for cereals, in accordance with the stipulations of
GB/T 21305 or GB/T 10362, determine the moisture content of the complete grains; for pulses,
in accordance with the stipulations of ISO 24557, determine the moisture content (ωH2O) of the
complete grains. Meanwhile, in accordance with 6.1, determine the mass of 1,000 grains.
7 Result Expression
7.1 The mass of 1,000 grains as received (m1) is obtained through Formula (1):
Where,
m1---the mass of 1,000 grains, expressed in (g);
mt---the mass of complete grains, expressed in (g);
N---the number of complete grains in the mass of mt.
7.2 The mass of 1,000 grains on the dry basis (m0) is obtained through Formula (2):
Where,
m0---the mass of 1,000 grains on the dry basis, expressed in (g);
m1---the mass of 1,000 grains as received, expressed in (g);
ωH2O---the moisture content of the sample, expressed in (%).
7.3 If the parallel determination results comply with the repeatability requirements (8.2), take
the arithmetic mean as the result; otherwise, re-sampling is required for determination. The
determination result of the mass of 1,000 grains is expressed in the unit of g. Significant digits
are retained as follows:
a) If the mass of 1,000 grains is less than 10 g, retain two digits after the decimal point;
b) If the mass of 1,000 grains is equal to or greater than 10g but does not exceed 100 g,
retain one digit after the decimal point;
c) If the mass of 1,000 grains is greater than 100 g, take an integer.
8 Precision
8.1 Interlaboratory Test
Details of the interlaboratory test precision of this Method are provided in Appendix A. For
other data ranges and test objects, these test data are for reference only.
8.2 Repeatability
The situation that the absolute difference between two independent test results obtained through
mutually independent tests conducted in the same laboratory, by the same operator using the
same equipment and the same test method, on the same test object in a short period of time is
greater than the repeatability limit r shall not exceed 5%.
The laboratory test results of wheat and barley whose mass of 1,000 grains on the dry basis is
between 29.8 g ~ 48.2 g are shown in Table A.1, Table A.2 and Figure A.1.
8.3 Reproducibility
The situation that the absolute difference between two independent test results obtained through
mutually independent tests conducted in different laboratories, by different operators using
different equipment and the same test method, on the same test object is greater than the
reproducibility limit R shall not exceed 5%.
......
 
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.