Abstract
Accuracy data (expressed as precision and trueness) presented by the authors of three different micro modifications of the Winkler titration procedure for dissolved oxygen concentration determination are critically evaluated. Tentative uncertainty estimates are extracted from the data based on the single-laboratory validation approach (originally published in the Nordtest Technical Report 537) and they lead to expanded uncertainty (k = 2) estimates in the range from 0.13 to 0.27 mg l−1 for the three procedures. It is demonstrated that, in all cases, the authors have presented the accuracy and/or precision estimates of the procedures in a way that can lead to too optimistic conclusions about the uncertainty of their procedures. This case study demonstrates the usefulness and flexibility of the single-laboratory validation approach to uncertainty estimation, even in the case of insufficient data, and can be of interest to laboratory workers dealing with measurement procedures from the literature. It is also expected to be of interest to university instructors of analytical chemistry and metrology in chemistry as a real-life example of the critical evaluation of the literature data.
References
Hitchman ML (1978) Measurement of dissolved oxygen. Wiley, New York, pp 71–123
Mancy KH, Jaffe T (1966) Analysis of dissolved oxygen in natural and waste waters. US Department of Health, Education, and Welfare, Public Health Service, Robert A. Taft Sanitary Engineering Center, Cincinnati, Ohio
Winkler LW (1888) Ber Dtsch Chemischen Ges 21:2843–2855. doi:10.1002/cber.188802102122
Carpenter JH (1965) Limnol Oceanogr 10:135–140
Carritt DE, Carpenter JH (1966) J Mar Res 24:286–318
International Organization for Standardization (ISO) (1983) Water quality—determination of dissolved oxygen—Iodometric method, ISO 5813. ISO, Geneva, Switzerland
Mortimer CH (1981) Mitt Int Ver Limnol 22:1–23
Benson BB, Krause D Jr (1980) Limnol Oceanogr 25:662–671
Jalukse L, Leito I (2007) Meas Sci Technol 18:1877–1886. doi:10.1088/0957-0233/18/7/013
International Organization for Standardization (ISO) (1990) Water quality—determination of dissolved oxygen—electrochemical probe method. ISO, Geneva, Switzerland
Winkler LW (1891) Ber Dtsch Chemischen Ges 24:3602–3610. doi:10.1002/cber.189102402237
Fox CJJ (1907) Publ Circ Cons Explor Mer 41:1–23
Fox CJJ (1909) Trans Faraday Soc 5:68–87. doi:10.1039/tf9090500068
Richards FA, Corwin N (1956) Limnol Oceanogr 1:263–267
Benson BB, Krause D Jr, Peterson MA (1979) J Solution Chem 8:655–690. doi:10.1007/BF01033696
Fox HM, Wingfield CA (1938) J Experim Biol 15:437–445
Krogh A (1935) J Industr Eng Chem 7:131–133
Krogh A (1935) J Industr Eng Chem 7:130–131
Whitney RJ (1938) J Exp Biol 15:564–570
Jalukse L, Vabson V, Leito I (2006) Accredit Qual Assur 10:562–564. doi:10.1007/s00769-005-0058-8
European Federation of National Associations of Measurement, Testing and Analytical Laboratories (EUROLAB) (2007) Measurement uncertainty revisited: alternative approaches to uncertainty evaluation. EUROLAB technical report no. 1/2007. EUROLAB, Paris, France. Available online at: http://www.eurolab.org/docs/technical%20report/Technical_Report_Measurement_Uncertainty_2007.pdf
Magnusson B, Näykki T, Hovind H, Krysell M (2004) Handbook for calculation of measurement uncertainty in environmental laboratories: edition 2. Nordtest technical report TR 537. Nordtest, Espoo, Finland. Available online at: http://www.nordicinnovation.net/nordtestfiler/tec537.pdf
Acknowledgments
This work was supported by the Estonian Science Foundation, grant no. 7449.
Author information
Authors and Affiliations
Corresponding author
Electronic supplementary material
Calculations with original data not described in detail in the text are available as electronic supplementary material. Below is the link to the electronic supplementary material.
Rights and permissions
About this article
Cite this article
Jalukse, L., Helm, I., Saks, O. et al. On the accuracy of micro Winkler titration procedures: a case study. Accred Qual Assur 13, 575–579 (2008). https://doi.org/10.1007/s00769-008-0419-1
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00769-008-0419-1