Evaluation of sampling mass for well mixed bulk materials with consideration of analytical variance

Abstract

An equation was derived for the evaluation of the critical sampling mass (CSM) for well mixed bulk materials. The CSM is the sampling mass at the critical situation that the total variance is not significantly different from the analytical variance, which is tested by the F-test method. The CSM, which is connected with the sampling constant, the content of the component to be determined and the analytical variance, was found to be very useful in estimating the representativity of sampling. The equation was applied to sampling for chemical analysis of silicon carbide with satisfactory results. It is applicable to any well mixed bulk material.

References

1. P. M. Gy, Analusis, 1995, 23, 497.
2. X.-W. He and W. Guo, Chin. J. Anal. Chem., 1995, 23, 1456.
3. B. Kratochvil, D. Wallace and J. K. Taylor, Anal. Chem., 1984, 56, 113R.
4. C. O. Ingamells and P. Switzer, Talanta, 1973, 20, 547.
5. J. Visman, Mater. Res. Stand., 1969, 11, 8.
6. D. Wallace and B. Kratochvil, Anal. Chem., 1987, 59, 226.
7. B. Kratochvil and J. K. Taylor, Anal. Chem., 1981, 53, 924A.
8. W. J. Youden, Statistical Methods for Chemists, Krieger, New York, 1977.
9. M. Thompson, Analyst, 1988, 113, 1579.
10. M. Thompson and R. J. Howarth, Analyst, 1976, 101, 690.
11. American National Standard, Standard Methods of Chemical Analysis of Silicon Carbide Abrasive Grain and Abrasive Crude, ANSI B74.15, 1971.
12. M. H. Ramsey, M. Thompson and M. Hale, J. Geochem. Explor., 1992, 44, 23.
13. M. Thompson and M. Maguire, Analyst, 1993, 118, 1107.
14. M. Thompson and M. H. Ramsey, Analyst, 1995, 120, 261.
15. M. Thompson and T. Fearn, Analyst, 1996, 121, 275.