|19th Needle/Leaf Interlaboratory Comparison Test - 2016/2017|
The following test samples were submitted to the participants:
1. Spruce needles (Slovenia)
2. Spruce needles (Austria)
3. Spruce needles (Austria)
4. Pine needles (Finland) - same sample like in the 6th and 7th test (sample 1)
Sample 1 was collected from Daniel ´lindra in Slovenia. Sample 2 was collected from Walter Wuggenig and his employees in Austria/Carinthia. Sample 3 was collected from Markus Neumann and his employees in Austria/Arnoldstein and Sample 4 was collected from Hannu Raitio 2002 in Finland. Special thank to all colleagues for collecting and preparing samples for this ringtest and special thank to the Dr. Gudmund Schütte Forst- und Gutsverwaltung for supporting this ringtest program with needles of a spruce tree.
The following participating laboratories with a lower percentage of correct results (less than 80%) have bigger QC/QA-problems in their laboratory and/or methodical problems:
A60 (77.4%), A43 (75.0%), F04 (75.0%), A39 (73.6%), F33 (67.3%), A86 (66.7%), A79 (60.0%), A62 (57.1%), A88 (51.4%) and A59 (4.2%)
Laboratory A86 (66.7%) has only special interest in analyzing sulphur, nitrogen and carbon. This lab failed with all samples for sulphur. This fact was the reason for the “low percentage of correct results”.
Figure 1: 19th Interlaboratory Comparison Test - Percentage of correct results (mandatory and optional elements)
Some of the ICP-Forests laboratories failed and had to do a re-qualification for some parameters (A60: P and Mn; A62: Ca, Mg and K; F06: Mg; F18: N, F33: C and Fe). These ICP-Forests laboratories had to check and re-validate their method or select another better method.
The laboratories A59 (C), A62 (Ca, Mg), A79 (Mg), A80 (Zn) and F33 (Fe) failed with the same parameter in the last test, so their QC/QA-problem is still not solved!
All interested laboratories are invited to take part in the re-qualification program up from now till 1st of September 2017.
More and more laboratories changed their method during the last years to microwave digestion and ICP-MS, so they are able now to determine heavy metals simultaneously with the mandatory and optional elements with a sufficient accuracy. Mercury can detect easily with a good accuracy with a special element analyzer or by AAS cold vapor technique. Heavy metals are an important air pollution indicator also with special interest within ICP-FORESTS.
The following additional elements are evaluated according DIN 38402: As, Cr, Co, Hg and Ni - these elements are analyzed at the moment from more than 10 participants. Mo, Tl and V are also evaluated according DIN 38402, but the number of participants is low.
Download report (1,7 MB)
Download special evaluation for heavy metals (0.9 MB)