UNCERTAINTY OF THE MEASUREMENTS RESULTS OF THE CHEMICAL COMPOSITION AND ITS METHODS ASSESSMENT

An explanation of the difference between the uncertainty and the error of the measurement results, which is in the approach to their assessment, is given. The standard and expanded uncertainty are estimated taking into account the uncertainty at each operation to transfer the size of a physical quantity from a standard (standard sample) to a measuring instrument and during measurements. The error is estimated based on the variance of the final measurement. Methods for evaluating the uncertainty of measurement results are given depending on regulatory documents, metrological characteristics, measurement methods, such as indicators and limits of repeatability and reproducibility.