Duplicate analysis in geochemical practice. Part I. Theoretical approach and estimation of analytical reproducibility

Authors:
  • MTMichael Thompson
    Michael Thompson
  • RHRichard J. Howarth
    Richard J. Howarth
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Abstract
Duplicate analytical results can be used to give rapid and realistic estimates of precision in analytical systems. In particular the effects of varying concentration of analyte on the variance of the measurement can be taken into account. When only small numbers of duplicate observations are available, the precision can be rapidly tested against an empirical standard level by use of a special control chart. Some common data-recording practices, however, can lead to erroneous estimates of detection limit, irrespective of the estimation procedure employed.