DANSK DS/ISO 11843-7 PDF

This part of ISO 11843 is concerned with mathematical methodologies for estimating the minimum detectable value in case that the most predominant source of measurement uncertainty is background noise which ubiquitously exists in analytical instruments whether or not a sample is applied to the instrument. The minimum detectable value can directly and mathematically be derived from the stochastic characteristics of the background noise. It specifies basic methods to – extract the stochastic properties of the background noise, – use the stochastic properties to estimate the standard deviation (SD) or coefficient of variation (CV) of the response variable, and – calculate the minimum detectable value based on the SD or CV obtained above. The methods described in this part of ISO 11843 are useful for checking the detection of a certain substance by various types of measurement equipment in which the background noise of the instrumental output predominates over the other sources of measurement uncertainty. Feasible choices are visible and ultraviolet absorption spectrometry, atomic absorption spectrometry, atomic fluorescence spectrometry, luminescence spectrometry, liquid chromatography and gas chromatography. The definition and applicability of the minimum detectable value are described in ISO 11843-1 and ISO 11843-2 and those of the precision profile are in ISO 11843-5. The precision profile expresses how the precision changes depending on the net state variable. Part 7 of ISO 11843 specifies the practical use of the fundamental concepts in ISO 11843 in case of the background noise predominance in instrumental analysis.