Accreditation and Quality Assurance

, Volume 11, Issue 5, pp 246–255 | Cite as

Uncertainty sources in UV-Vis spectrophotometric measurement

  • Lilli Sooväli
  • Eva-Ingrid Rõõm
  • Agnes Kütt
  • Ivari Kaljurand
  • Ivo Leito
Practitioner's Report

Abstract

An overview is given of the most important uncertainty sources that affect analytical UV-Vis spectrophotometric measurements. Altogether, eight uncertainty sources are discussed that are expected to have influence in chemical analysis. It is demonstrated that the well-known intrinsic (or “physical”) sources of uncertainty that originate from the instrument itself (repeatability of spectrophotometer reading, spectrophotometer drift, stray light, etc.) often have significantly lower contributions to the combined uncertainty of the result than the “chemical” sources of uncertainty that originate from the object under study (interference from the constituents of the matrix, decomposition of the photometric complex, etc.). Although selectivity of a photometric procedure is often considered more a validation topic than an uncertainty topic, it is very often important to include it also in the uncertainty budget.

Usually the most difficult part of uncertainty estimation of a chemical measurement result is to evaluate the magnitude of the actual uncertainty components, especially the chemical ones. For most of the uncertainty sources discussed in this paper, approaches for their evaluation are given. A generic uncertainty budget for absorbance is presented.

Keywords

UV-Vis spectrophotometry Measurement uncertainty Uncertainty sources Drift Repeatability Nonlinearity Selectivity 

Supplementary material

769_2006_124_MOESM1_ESM.pdf (21 kb)
Metrology Infrastructure in Gas Analysis
769_2006_124_MOESM2_ESM.xls (26 kb)
Metrology Infrastructure in Gas Analysis
769_2006_124_MOESM3_ESM.xls (52 kb)
Metrology Infrastructure in Gas Analysis

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Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  • Lilli Sooväli
    • 1
  • Eva-Ingrid Rõõm
    • 1
  • Agnes Kütt
    • 1
  • Ivari Kaljurand
    • 1
  • Ivo Leito
    • 1
  1. 1.Institute of Chemical PhysicsUniversity of TartuTartuEstonia

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