Results of the 18 th and 19 th Needle/Leaf Interlaboratory Comparison Tests

Transcription

1 Results of the 18 th and 19 th Needle/Leaf Interlaboratory Comparison Tests Alfred FÜRST Meeting of the Working Group QA/QC in Laboratories Zagreb/Croatia March 2017

2 Overview General information about both tests Main Results Common methods Problematic parameters/laboratories Re-qualification after the 18th Test Reference samples Ongoing foliage ringtest program Enlarge parameter list (heavy metals)

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4 Countries/Laboratories Interlaboratory Comparison Test Number of countries Number of laboratories 5 th th th th th th th th th th th th th th th 22 45

5 Participating labs decreasing Stop funding of the monitoring program Participating only in uneven years - paralell to the monitoring activities Closing and/or merging of labs Costs of the ringtest

6 240 are too expensive? = 7 l nitric acid 65% = 100 ml multielement standard = one PTFE vessel for microwave digestion = 4 working hours of a lab worker And how expensive are wrong results??

7 Comparison between 7 th and 19 th Interlaboratory Comparison Test Element 7 th Test 2004/05 (Sample 1) 19 th Test 2016/17 (Sample 4) (Unit) Mean Number of Labs Mean Number of Labs N mg/g S mg/g P mg/g Ca mg/g Mg mg/g K mg/g C g/100g 29 34

8 Comparison between 7 th and 19 th Interlaboratory Comparison Test Element 7 th Test 2004/05 (Sample 1) 19 th Test 2016/17 (Sample 4) (Unit) Mean Number of Labs Mean Number of Labs Zn µg/g Mn µg/g Fe µg/g Cu µg/g Pb µg/g Cd ng/g B µg/g 21 18

9 Difficult Samples & Elements 18th Test 1. Beech Leaves + B - Pb 2. Pine Branches + Fe, Cd - N, S, P, Ca, Mg, K, B 3. Spruce Needles - Pb 4. Spruce Needles - Pb 19th Test 1. Spruce Needles - Pb 2. Spruce Needles - Pb 3. Spruce Needles + Zn, Pb, Cd 4. Pine Needles - Ca, B, Pb too low content for evaluation

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12 % 20 Percentage of non tolerable results in Needle/Leaf samples S P Ca Mg K N

13 Labs failed with the same element/s in both tests Germany A59 (C) Germany A79 (Mg) Germany A80 (Zn) ICP-Forests lab - Croatia A62 (Ca, Mg) ICP-Forests lab - Spain F33 (Fe)

14 What influences data quality? Results of the questionaire Laboratory accreditation Higher number of analyzed samples/a Control charts Staff trained on the method/matrix More than one ringtest participations/a

15 Pretreatment methods 2016/17 Element open digestion pressure digestion microwave dry ashing pellet noorother pretreatment N 9 29 S P Ca Mg K C Zn Mn Fe Cu Pb Cd B

16 Changes in pre-treatment methods from 2006 till 2017 N: open digestion no digestion (element analyzers) Dry ashing open digestion (P, K, Ca, Mg, Mn) or to microwave Pressured digestion microwave

17 Determination methods 2016/17 Element Elementanalyzer N 29 Flame-AAS & AES Flameless-AAS ICP-AES ICP-MS other 9 (Kjeldahl) 1 (UV-VIS) S (X-Ray) 3 (X-Ray) P (UV-VIS) Ca (X-Ray) Mg (X-Ray) K (X-Ray) C 32 1 Zn (X-Ray) Mn (X-Ray) Fe (X-Ray) Cu (X-Ray) Pb Cd B 14 4

18 Changes in determination methods from 2006 till 2017 N: Kjeldahl method Element analyzers Flame-AAS ICP-AES Flameless AAS ICP-MS ICP-AES ICP-MS

19 Element Tolerable 17 th Labtest 18 th Labtest 19 th Labtest limits 2014/ / /2017 (± %) Non Number of Non Number of Non tolerable mean mean tolerable values values tolerable (%) (%) (%) Number of mean values N , ,6 152 S , ,4 148 P , ,4 164 Ca , ,3 168 Mg , ,1 168 K , ,7 168 C , ,1 136 Zn , ,1 132 Mn , ,8 136 Fe , ,3 128 Cu , ,2 132 Pb ,0 75 7,7 24 Cd , ,1 96 B , ,9 72 +

20 Compare your results from the last tests - what happend? N S P Ca Mg K C Zn Mn Fe Cu Pb Cd B 16th Test > 17th Test >> > 18th Test >> > <>> <> <>> 19th Test > << < < < < >>>> < <<<< C, N (other element analyzer) Pressure digestion / ICP-MS Always problems with Fe! What is with B in the last test? Is no accredited testing laboratory Lab uses a mean, a range and a blank control chart and check nothing? plant samples/a Good trained staff on the method/analytical equipment

21 Compare your results from the last tests - what happend? N S P Ca Mg K C Zn Mn Fe Cu Pb Cd B 16th Test > 17th Test >> > 18th Test >> > <>> <> <>> 19th Test > << < < < < >>>> < <<<< C, N (other element analyzer) Pressure digestion / ICP-MS Always problems with Fe! What is with B in the last test? Is no accredited testing laboratory Lab uses a mean, a range and a blank control chart and check nothing? plant samples/a Good trained staff on the method/analytical equipment

22 Compare your results from the last tests - what happend? N S P Ca Mg K C Zn Mn Fe Cu Pb Cd B 17th Test > >> >> <<< >>> >>> > >>>> > 18th Test < <<<< 19th Test << >>>> >>>> >>>> >>>> >>>> <<<< >>>> >>>> >>>> >>>> >>>> C is always too low (Element analyzer) no improvement Open digestion method & ICP-AES contamination? Changes in the laboratory staff? Wrong samples? No accredited testing laboratory Lab uses a mean chart and blank chart and check nothing? samples/a correct analyzed samples! Good trained staff on the method/analytical equipment

23 Compare your results from the last tests - what happend? N S P Ca Mg K C Zn Mn Fe Cu Pb Cd B 17th Test > >> >> <<< >>> >>> > >>>> > 18th Test < <<<< 19th Test << >>>> >>>> >>>> >>>> >>>> <<<< >>>> >>>> >>>> >>>> >>>> C is always too low (Element analyzer) no improvement Open digestion method & ICP-AES contamination? Changes in the laboratory staff? Wrong samples? No accredited testing laboratory Lab uses a mean chart and blank chart and check nothing? samples/a correct analyzed samples! Good trained staff on the method/analytical equipment

24 What is a good result? Accuracy of the mean & precision % Recovery % Vi % % Recovery % Vi %

25 What is a good result? % Recovery close to 100% with a small variation between the four sample results (= your method is under control) Vi (variation between the replicates) element analyzer (measurement without extra sample preparation) < 3% Macro elements (P, K, Ca, Mg, K) < 5% Micro elements and heavy metals < 10% Trace elements < 20%

26 Reasons for Re-Qualification after the 18 th Needle/Leaf Ringtest Technical problem / no servicing of the instrument (5 labs) Calibration error (one lab) Methodical problem / method changed (one lab) Missed data submission deadline or got no samples (one lab) No dry matter correction (one lab)

27 Re-Qualification after the 19th Needle/Leaf Ringtest Is mandatory for all ICP-Forests laboratories if they plan to: Submit monitoring results from the sampling period 2016/17 to the PCC database ( growing saison 2016) Deadline 1 st September 2017

28 Re-Qualification Use in all communications your lab code number Use in any case the xls-form for your requalification: Submit all printouts. calibration. dilution factors. (= I should be able to recalculate your results!) What was the reason (or your opinion) for missing the qualification? Think on measures to avoid errors in future!

29 FFCC offers reference materials Spruce needles A Maple leaves A Litterfall (beech leaves) Pine needles (Pinus nigra) Spruce needles B (+heavy metals)

30 Spruce needles B New Element N/L Unit Mean S R N 140/35 mg/g S 136/34 mg/g P 156/39 mg/g Ca 160/40 mg/g Mg 156/39 mg/g K 156/39 mg/g Zn 127/32 µg/g Mn 128/32 µg/g Fe 124/31 µg/g Cu 128/32 µg/g Pb 56/14 µg/g Cd 76/19 ng/g B 68/17 µg/g C 135/34 g/100g As 32/8 ng/g Co 64/16 µg/g Cr 88/22 µg/g Hg 52/13 ng/g Mo 32/8 ng/g Ni 90/23 µg/g Tl 24/6 ng/g V 36/9 µg/g

31 20th Needle/Leaf Interlaboratory Test 2017/18

32 Statistical evaluation for heavy metals Heavy metals Heavy metals

33 Enlarge parameter list Use of multielement methods (ICP-AES, ICP-MS) no additional costs/time Ringtest participation (> 10 laboratories) Repetitious accuracy

34 Enlarge parameter list Above the element symbol you can see the number of participants in the last test.

35 Element common Method Number of labs low content Arsenic ICP-MS ng/g % Cobalt ICP-MS/ (ICP-AES) µg/g % Chromium ICP-AES µg/g % Mercury ICP-MS / Element analyzer ng/g % Nickel ICP-AES µg/g % high content 127 ng/g % 0.47µg/g % 4.24µg/g % 70.6ng/g % 5.36µg/g % Element common Method Number of labs low content high content Cadmium ICP-MS/ GF-AAS ng/g % 294ng/g % Lead ICP-MS/ GF-AAS µg/g % 27.1µg/g %

36 Element common Method Number of labs low content Arsenic ICP-MS ng/g % Cobalt ICP-MS/ (ICP-AES) µg/g % Chromium ICP-AES µg/g % Mercury ICP-MS / Element analyzer ng/g % Nickel ICP-AES µg/g % high content 127 ng/g % 0.47µg/g % 4.24µg/g % 70.6ng/g % 5.36µg/g % Element common Method Number of labs low content high content Cadmium ICP-MS/ GF-AAS ng/g % 294ng/g % Lead ICP-MS/ GF-AAS µg/g % 27.1µg/g %

37 Thank you for your attention!