Accreditation and Quality Assurance

, Volume 11, Issue 8–9, pp 462–469 | Cite as

Chlorophyll-a determination: results of an interlaboratory comparison

  • Petra SchillingEmail author
  • Martin Powilleit
  • Steffen Uhlig
Practitioner's Report


A chlorophyll-a interlaboratory comparison was carried out to compare three different analytical chlorophyll-a determination methods: a German standard DIN 38412-16, a method of the HELCOM-Combine-Manual and the different “in-house” methods of participating laboratories. Eleven laboratories took part. They had to determinate the chlorophyll-a and phaeopigment content in two seawater samples taken from the Baltic Sea. Furthermore, for the assessment three different statistical evaluation methods were applied: the German standard DIN 38402-42, the Q-method combined with an estimator according to Huber and the Cofino-method. All analytical methods were appropriate to determine the chlorophyll-a content. The relative standard deviations of reproducibility for chlorophyll-a varied between 12 and 31%. None of the analytical methods was appropriate to determine the phaeopigment content quantitatively. The relative standard deviations of reproducibility for phaeopigments ranged between 87 and 158%. The applied statistical evaluation methods resulted in different assessments. The Q-method combined with an estimator according to Huber proved to be the best qualified method.


Chlorophyll-a Cofino-method Interlaboratory comparison Marine monitoring Phaeopigments 



The authors would like to thank Renate Deutschmann and Eva Schmidt for their excellent technical assistance and all laboratories for participating in the interlaboratory comparison.


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Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  • Petra Schilling
    • 1
    Email author
  • Martin Powilleit
    • 2
  • Steffen Uhlig
    • 3
  1. 1.Laboratory for Water AnalysisFederal Environmental AgencyBerlinGermany
  2. 2.University of RostockInstitute of Biological Sciences, Marine BiologyRostockGermany
  3. 3.quo dataGesellschaft für Qualitätsmanagement und Statistik mbHDresden-LangebrueckGermany

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