results of the 18 and 19 needle/leaf interlaboratory...
TRANSCRIPT
Alfred FÜRST
Forest Foliage Co-ordinating Centre
Pallanza/Italy 7.9. – 8.9.2017
ICP-FORESTS - 6th Meeting of the Heads of the Laboratories
Results of the 18th and 19th Needle/Leaf Interlaboratory Comparison Tests
Overview
General information about both tests
Main results
Common methods
Problematic parameters / laboratories which failed in both tests
Re-qualification 18th and 19th test
Reference samples
Enlarge parameter list (heavy metals)
Ongoing foliage ringtest program
Database update with new parameters
Needle/Leaf Interlaboratory Comparison tests
Countries/Laboratories
Participating labs decreasing
Stop funding of the monitoring program
Participating only in uneven years - paralell to the monitoring
activities (20th, 18th, 16th Test, ….)
Closing and/or merging of labs
Costs of the ringtest…
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??
+
Comparison between 7th and 19th Test
Comparison between 7th and 19th Test
Difficult Samples & Elements
+
Percentage of non tolerable results in
Needle/Leaf samples
%
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)
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Re-qualification process
Please, ask your colleagues if they have similar problems!
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
Pre-treatment methods 2016/17
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
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Microwave digestion & Temperature
Target temperature should be 200°C for 20 minutes
In reality:
max. temperature:
111-168°C for oneminute!
+
Determination methods 2016/17
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
Training-course needed!
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ICP-AES / plant samples
Use standards with similar concentration like your samples
Use matrix adapted standards with similar acid & element
concentrations
Use enough standards (>3) depending on the selected
correlation function (linear, quadratic, regressed, weighted)
Check the calibration with an seperate prepared independent
sample/standard solution
On dual view systems: use radial view for Ca, (Mg), K - all other
elements can be measured in axial view with higher
sensitivity
Calibration ICP-AES / plant samples
„Normal conc. range“ of the sample in mg/l
„Check Standard“
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There are more things in heaven
and earth than you are dreamed of…
in ICP measurement too…!
Training-course needed!
+
Drying of standard materials for CNS
element analyzers
Reason was a not (enough) dried
coal standard material…
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?
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 > << < < < < >>>> < <<<<
„Is no accredited testing laboratory“
„Lab uses a mean, a range and a blank control chart“
and check nothing?
„100-500 plant samples/a“
„Good trained staff on the method/analytical equipment“
Compare your results from the last
tests - what happend?
C is always too low („Element analyzer“) – no improvement
„Open digestion method & ICP-AES“ contamination?
Changes in the laboratory staff? Wrong samples?
N S P Ca Mg K C Zn Mn Fe Cu Pb Cd B
17th Test > >> >> <<< >>> >>> > >>>> >
18th Test < <<<<
19th Test << >>>> >>>> >>>> >>>> >>>> <<<< >>>> >>>> >>>> >>>> >>>>
Compare your results from the last
tests - what happend?
„No accredited testing laboratory“
„Lab uses a mean chart and blank chart“ and check nothing?
„1000-5000 samples/a“ 50-250 correct analyzed samples!
„Good trained staff on the method/analytical equipment“
N S P Ca Mg K C Zn Mn Fe Cu Pb Cd B
17th Test > >> >> <<< >>> >>> > >>>> >
18th Test < <<<<
19th Test << >>>> >>>> >>>> >>>> >>>> <<<< >>>> >>>> >>>> >>>> >>>>
What is a good result?
Accuracy of the mean & precision
% Recovery = 97.79 – 99.93% Vi = 0.60-1.17%
% Recovery = 86.22 – 131.2% Vi = 2.97-7.89%
This is a good result!
% Recovery close to 100% with a small variation between the four
sample results and without influence of the sample concentration
(= your method is under control)
Vi (variation between the four replicates)
o element analyzer (measurement without extra sample preparation) < 3%
o Macro elements (P, K, Ca, Mg, K) < 5%
o Micro elements and heavy metals < 10%
o Trace elements < 20%
Reasons for Re-Qualification
Technical problem / no servicing of the instrument (6 labs)
Calibration error (3 labs)
Methodical problem / method changed (4 labs)
Missed data submission deadline or got no samples (one lab)
Calculation error ( 2 lab)
No dry matter correction (2 labs)
FFCC offers reference materials
Maple leaves A
Litterfall (beech leaves)
Pine needles (Pinus nigra)
Spruce needles B (+heavy metals)
http://bfw.ac.at/rz/bfwcms2.web?dok=5146
www.ffcc.at
Spruce needles B New
Statistical evaluation for heavy metals
Heavy metals Heavy metals
Enlarge parameter list
Use of multielement methods (ICP-AES, ICP-MS)
no additional costs/time
Ringtest participation (> 10 laboratories)
Repetitious accuracy
New parameter up from the 20th Test
Above the element symbol you can see the number of participants in the last test.
Evaluation limits
Finalized on the EP Meeting Foliage and Litterfall in Zagreb/TFM Luxembourg 2017
Parameter list / 20th Test
Ringtest samples / 20th Test
Sample 1 - Birch leaves (Austria)
Sample 2 - Spruce needles (Germany)
Sample 3 - Spruce needles (Austria)
Sample 4 - Pine cones (Austria)
Ringtest material is needed – especially from broadleaves trees
+
Database update – FOM/LFM Forms
FOM - Sampling and Analysis of Needles and Leaves
LFM - Sampling and Analysis of Litterfall
Arsenic
Cobalt
Chromium
Mercury
Nickel
Database update - d_parameter_lfCODE DESCRIPTION FROM_YEAR TO_YEAR UNIT
Al Aluminium 2009 2007 mg/g
B Bor 2009 µg/g
C Carbon 2009 g/100g
Ca Calcium 2009 mg/g
Cd Cadmium 2009 ng/g
Cu Copper 2009 µg/g
Fe Iron 2009 µg/g
K Potassium 2009 mg/g
Mg Magnesium 2009 mg/g
Mn Manganese 2009 µg/g
N Nitrogen 2009 mg/g
Na Sodium 2009 2007 mg/g
P Phophor 2009 mg/g
Pb Lead 2009 µg/g
S Sulphur 2009 mg/g
Zn Zinc 2009 µg/g
As Arsenic 2017 ng/g
Co Cobalt 2017 µg/g
Cr Chromium 2017 µg/g
Hg Mercury 2017 ng/g
Ni Nickel 2017 µg/g
Thank you for your attention!