The quality of analytical measurements

In most analyses we rely on chemical samples to give us information about a whole object. So unless the sampling stages of an analysis are considered carefully, the statistical methods discussed in this book may be invalidated, as the 

From the random sample, the mean, x, and variance, s, can be calculated. There are two contributions to sh the sampling variance, oi, due to differences between the members of the sample, e.g. the tablets having different weights, and 

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LGC has a strong interest in the quality of analytical measurements and played a lead role in the development of the UK s initiative on Valid Analytical Measurement (VAM). This is a programme supported by the UK government as part of the DTI programmes supporting the national measurement system. 

The preparation of this book was supported under contract with the Department of Trade and Industry (DTI) as part of the National Measurement System (NMS) Valid Analytical Measurement (VAM) Programme. The latter aims to improve the quality of analytical measurement in the UK. 

Results of analytical measurements are a kind of a product of the chemical analyst s work. Both manufactured products (object of analysis) and analytical results must be of an appropriate quality. In addition, the quality of analytical measurements appears to have its own accumulative requirement the quality of every product is a result of comparison of the obtained value (anal3dical result) with the reference value (expected, standard, norm, required). In order for the obtained result to be comparable (authoritative, reliable) to the reference value, its (high) quality must be documented and maintained. The quality of analytical results must be assured in the first place before drawing conclusions about the quality of the examined products. 

Advisory Group meetings are held once every two years, attended by representatives of SAL and NWAL together with other Agency and national experts to review the quality of analytical measurements for safeguards. 

Essentially, there are two mechanisms by which the quality of analytical measurements made in the United Kingdom can be improved by the producers improving the quality of the analytical measurements they supply by the users of analytical measurements demanding an improvement in the quality of analytical measurements they procure. 

MUler, J. N., and J. C. Miller, "Chapter 4 The Quality of Analytical Measurements," in Statistics and Chemometrics for Analytical Chemistry, 4th ed. Upper Saddle River, NJ Prentice Hall, 2000. 

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