You are here:  PROOF-ACS > Competence Schemes > P1906-MRT Acidic herbicides incl. hydrolysis - orange

Acidic herbicides incl. hydrolysis (P1906-MRT, former P1804-MRT)

The residue definitions of acidic herbicides according to regulation (EC) No. 396/2005 include the esters, salts and conjugates of the respective herbicides. The conjugates can contribute significantly to the total amount of the respective herbicides determined in routine samples. An alkaline hydrolysis step is applied to quantify residues of the conjugates in routine samples.

Up to now, the hydrolysis has not been included in proficiency tests. P1906-MRT is designed to cover all aspects of the analysis of acidic herbicides in accordance with the residue definition.

For that purpose the test material is spiked with selection of

  • conjugates of acidic herbicides
  • esters of acidic herbicides
  • and the free acids of acidic herbicides.

In order to ensure that the results are unambiguously, either the conjugate or the ester or the free acid is spiked for each of the selected herbicide. In case of one of the herbicides, the conjugate, an ester and the free acid is spiked to simulate the residue situation in routine samples. Acidic herbicides within the scope of the test are summarised here.

It is essential to apply an alkaline hydrolysis for this method ring test. An analysis of the esters and the free acids only results in an underestimation of the spiked levels!

The results after alkaline hydrolysis (sum of conjugates, esters and free acids) are considered for evaluation. 

The analytical data are assessed with respect to

  • the comparability (z-score), and
  • the trueness (70 to 120% of the spiked level).

The test material consists of a spiked orange homogenate (100 g).

Expected time schedule

  • Registration:
    15 February 2019
  • Dispatch of samples:
    1 April 2019
  • Deadline for reporting results:
    25 April 2019


The participation fee is 750 EUR. The corresponding blank material is available at a price of 70 EUR.

The test material is shipped by express courier. Shipping costs are included for shipment to EU countries. Additional shipping costs may apply for shipment to Non-EU countries.
Please feel free to contact us to get an individual quote. 

Please feel free place your orders via the Order/login section on the website.

Note: PROOF-ACS reserves the right to cancel tests in case of less than ten participants.