9th Needle/Leaf Interlaboratory Comparison Test - 2006/200754 European laboratories from 29 countries participated in this test - 53 were sending 10944 results. 4 samples were sent:
- Sample 1 (Spruce needles/Germany)
- Sample 2 (Spruce needles/Germany)
- Sample 3 (Oak leaves / United Kingdom)
- Sample 4 (Oak leaves/Hungary) is indent with sample 3 from the 6th test
The results of the 9th Interlaboratory Comparison Test show generally a good analytical quality in foliar analysis. Especially the results of the mandatory elements (N, S, P, Ca, Mg, K) are quite good and much better than in the tests before. Some of the laboratories had to learn from their ringtest results and had to improve their quality and had to make a revision of their method, especially those with statistic outliers and/or results outside of the tolerable limits (laboratories 30, 23 and 74). A few laboratories must change their methods completely (e.g. dry ashing, nephelometry determination of sulphur), because this methods are not recommended and not state of the art. Calibration Problems with element analysers are back again. Most of the labs (close to 90%) are using control charts as a daily routine procedure. The data quality of the laboratories, which are participating in the ICP-Forests - Level II foliar survey 2006, is good - only two laboratories (23 and 74) have bigger problems.
Results of the "Level II - laboratories"
The Report of the 9th Needle/Leaf Interlaboratory Comparison Test can be downloaded here:
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