Domestic Round Robin Interlaboratory Test on Ultimate Analysis by Instrumental and JIS Method

Abstract

Sampling Research Committee for Bulk Materials, JUSE prepared an original plan for revision of “JIS M8813 Ultimate Analysis of Coal and Coke” in F. Y 1985-1987.
In order to adopt to instrumental elementary analysis as JIS standard, domestic round robin in-terlaboratory test on the ultimate analysis was carried out according to the instrumental and the JIS method. The experimental results are as follows:
1. As for the precision withein laboratories on the carbon and sulfur content obtained in the same labolatory, the instrumental method was superior to the JIS analysis. For the nitrogen content, the JIS method was superior. For the hydrogen content, both method exhibited almost the same preci-sion.
2. As for the precision between laboratories obtained indifferent laboratories, the JIS method presented a higher precision that the instrumental method on all the test items.
3. As for the precision between measurement values caused by the different analyses, a signifi-cant difference was found in the measurement values on the carbon, hydrogen and nitrogen contents of the coke, on the nitrogen content of Daido coal, and on the sulfur content of high and middle sulfur coal.
4. The Permissible tolerance of the measurement values on the carbon content obtained in the precision within and between laboratories by the instrumental method, and that obtained in the preci-sion within laboratories by the JIS method exceeded the permissible tolerance by the JIS standard.
5.The permissible tolerance of the measurements on the nitrogen content obtained in the preci-sion within laboratories by the instrumental method exceeded that specified by the JIS standard.
6. The permissible tolerance of the measurements on the sulfur content of the high sulfur coal obtained in the precision between labolatories by the instrumental and the JIS method exceeded that specified by the JIS standard.
In view of the foregoing, it was decided that the instrumental method, of which the permissible tolerance is to be the same as that of the JIS method should be adoptedas JIS standard. For adoption of the instrumental method, the following should be considered.
a. The performance of used instrumental analytical apparatus should be specified so that the measurement can be conducted within the permissible tolerance.
b. Method for the calibration of used instruments' analytical apparatus shoud be specified.
c. It should be specified that the skill of a measurement technician is levelled up so that the can carry out the measurement of samples within the permissible tolerance.