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Limit of Quantitation in Atomic Spectrometry–Concepts and Definitions

Atomic Spectroscopy

  1. Jean-Michel Mermet

Published Online: 15 DEC 2009

DOI: 10.1002/9780470027318.a9126

Encyclopedia of Analytical Chemistry

Encyclopedia of Analytical Chemistry

How to Cite

Mermet, J.-M. 2009. Limit of Quantitation in Atomic Spectrometry–Concepts and Definitions. Encyclopedia of Analytical Chemistry. .

Author Information

  1. Spectroscopy Forever, Tramoyes, France

Publication History

  1. Published Online: 15 DEC 2009

Abstract

Classical definition of the limit of quantitation (LOQ) based on 10 times the standard deviation (SD) of the blank fluctuations is described in terms of relation with the limit of detection (LOD) and the limit of guarantee of purity (LOG), including the use of hypothesis testing. Reliability of the determination of the SD of the blank is discussed in terms of Gaussian distribution, possible presence of outliers, and influence of the number of replicates. Following norms, various concepts of precision are defined, namely, instrumental repeatability, method repeatability, intermediate precision, and within- and between-laboratory reproducibility. Trend to include systematic and random errors in the concept of LOQ is described with a discussion about the past and present meaning of accuracy. Because of the need to have a signal-to-concentration conversion, limitations resulting from the calibration graph are given.

Keywords:

  • limit of quantitation;
  • limit of quantification;
  • limit of detection;
  • precision;
  • accuracy;
  • uncertainty due to calibration;
  • atomic spectrometry