48 laboratories in 23 countries participated in the 23rd Needle/Leaf Interlaboratory Test, but only 47 laboratories send their results in time.

The following test samples were submitted to the participants:

1. Beech leaves (Austria)
2. Spruce needles (Slovenia) - same sample like in the 19th Test (Sample 1)
3. Spruce needles (Austria)
4. Ash leaves (Belgium)

Sample 1 was collected in Lower Austria (Reinhard Hagen & Michael Fransche). Sample 2 was collected and prepared in Slovenia (Daniel Zlindra). Sample 3 was collected and prepared from BFW/Austria. Sample 4 was collected and prepared from Belgum (Bruno de Vos).
Special thank to all colleagues for collecting and preparing samples for this ringtest.

Figure 1: 23rd Interlaboratory Comparison Test - Percentage of correct results (mandatory and optional elements)

The following participating laboratories with a percentage of correct results below 80% have severe QC/QA-problems, a miscalculation of the results and/or methodical problems:

A85 (78.6%), F09 (75.0%), F24 (69.8%), F07 (61.2%), A88 (58.0%), A56 (51.1%) and S22 (25.9%)

Some of the ICP-Forests laboratories failed and a re-qualification is obligatory for certain parameters (A85: S; F07: P, Ca, K, Cu, As; F12: Co; F24: P, Zn; S22: P, Ca, Mg, K, Mn, Fe, Cu, B, As, Cr, Ni). These ICP-Forests laboratories have to check and re-validate their methods or employ better applicable methods. FFCC offers old ringtest materials, if a reference material is needed for this purpose.

The laboratories A43 (P), A88 (P, Ca, Mg, K, Zn), A59 (C), A65 (Pb) and F07 (As) failed with the identical parameters in the last test(s). Therefore, their QC/QA-problem or their methodical problem is still not solved!

All interested laboratories are invited to take part in the re-qualification program up from now till 1st of August 2021.

Download final report (5.6 MB)