International Plant-analytical Exchange - IPE

Proficiency tests

Participation is open to all laboratories.


Test programme Plant
Number of rounds 4 per year
Number of samples 4 per round
Sample size 20 g
Origin Natural source
Exercise name IPE

General Information

  • The sample types/matrices are chosen to represent the materials which you normally analyse.
  • The plant samples are dried at max. 70°C and milled and sieved to <0.5 mm.
  • The homogeneity of each batch of samples is tested on a selection of parameters.
  • The dried plant samples are stored at -20°C and are stable over a number of years.
  • You analyze the test materials according to your normal validated methods and procedures for those elements and parameters you are interested in.
  • Your results are processed at WEPAL-QUASIMEME and published every three months under confidential code names.
  • The reports contain all data, statistical evaluation including Z-score plots and method information about the method used.
  • Your reports are available within three weeks after the submission deadline.
  • New determinands can be added on request.

Determinands and analysis

Major and Trace Elements

Determinand group

  • Inorganic Chemical Composition (Nutrients, major and trace elments)
  • Real totals (Elements including silicates)
  • Acid extractabel inorganic composition (so-called totals) (Elements excluding silicates)

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Nutricional values

Determinand group

  • Nutricional values

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Other determinations

Determinand group

  • Isotopes

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Exchangeable cations

Determinand group

  • Act. CEC using cobaltihexamine (AFNOR NFX 31 130)
  • Act. CEC using 0.01M BaCl2 (ISO 11260)
  • Act. CEC using 0.1M BaCl2 (UNEP-UN/EC 91065A)
  • Pot. CEC using 1M NH4-acetate at pH=7
  • Pot. CEC using 1M or 0.1M BaCl2-TEA at pH=8.1 (ISO 13536 OR BZE)
  • Pot. CEC using 1M NH4Cl (BZE)

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Others and Experimental

Determinand group

  • Other determinations (Moisture content, CN detn, stable isotope ratios, additional extractions)

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Webshop

Samples of previous proficiency tests are sold as reference materials. Available materials can be selected and ordered in our webshop. Participants of our proficiency tests are entitled to a discount.