GB/T 5519-2018Cereals and pulses -- Determination of the mass of 1 000 grains (English PDF)

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.

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.

6.1 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 (omegaH2O) of the complete grains. Meanwhile, in accordance with 6.1, determine the mass of 1,000 grains.

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);

omegaH2O---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.

8.1 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%.