DANSK DS/ISO 12828-1 PDF

In this Standard, Limits of Detection (LD) and Limits of Quantification (LQ) are defined and calculated. The Standard provides methods for determining suitable values for these two parameters for a specific analytical procedure and for a specific chemical species. Care is needed in defining the required LD and LQ levels for a given analysis and application to avoid setting unnecessarily low limits. This could prove expensive, time consuming and impose undue technical restraints, with little or no effect on the accuracy and precision of the end use of the data. The use of this Standard fulfils the requirement in ISO 17025 that a laboratory carrying out chemical analysis (e.g., of fire effluents) is able to characterise and evaluate a method by such parameters as the LD, LQ, and uncertainty. Examples of where the information contained in this Standard can be applied are: 1. Method validation: These parameters (i.e., LD and LQ) are required for all chemical analytical methods; they are as important as measurements of accuracy and precision. 2. Classifications based on toxicity indexes: A toxicity index can never be measured as zero when concentrations of toxic species are detected., because a contribution of at least equal to the limit of detection for each measured species will be registered. Examples are shown in annex B. 3. Round robin comparison between two analytical methods: For a given working range, two methods can be compared only if the limits of these methods (as calculated by using this Standard) are similar for the lower range of concentrations to be measured. For example, if one laboratory provides values near its own limit of detection, and another laboratory gives results well above its own limit of detection, the reproducibility assessment of the round robin will be artificially overestimated. In many round robin tests, bad reproducibility values can be found if some values are close to the limit of quantification and/or limit of detection. In such cases, no conclusion on the round robin can be given without an assessment of the limit of quantification value and the expression of results as described in this Standard. Examples of existing Standards where the information contained in this Standard can be used are the analytical chemical methods in ISO 19701 [2], ISO 19702 [3], ISO 5660-1 [7], and the chemical measurements in the methods discussed in ISO/TR 16312-2 [8].