Consultancy mission report to the Phillipine Coconut Authority (PCA) Quezon City, Manila, Philippines, 11th May to 31st May 1999. Installation and operationalization of the plant tissue analysis laboratory of the Philippine Coconut Authority

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Département Amélioration des

Méthodes pour l'innovation

Scientifique

Cirad-amis

Consultancy Mission Report

To the Phillipine Coconut Authority (PCA) Quezon City, Manila, Philippines

11th

May to 31st May 1999

Installation and operationalization of

the Plant Tissue Analysis Laboratory of

the Philippine Coconut Authority

-

-Paul FALLAVIER Programme AGRONOMIE Département AMIS 8 Juin 1999 n° 26/99

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Summary:

The building of the laboratory is conforming the layouts and facilities described in the report mission of October 1995. However, later a third floor extension has been decided. The works have to be done without any disturbance for the PTAL laboratory.

The delivery of the equipment is now completed, with some miner defects whithout consequence for the operation.

The tests of the equipment are satisfactory, except for the elemental analyser which needs some more adjustements to be operational. For the ICP spectrometer, the typical relative standard deviation (%RS0) is between 1 and 2%. This spectrometer is steady and easy to use. The test of the atomic absorption spectrometer was made by analysing 20

mineralization solutions of the same sample. The %RS0 was 1.72%. This result, obtained without the sampler, is good. For the colorimeter, the typical %RS0 is lower than 1 %. Detailed results and errer computation are in the annexe of the report.

The training and mission program was revised because of the end of the project in December 1999. Two trainings will take place in June (Perkin-Elmer in Malaysia) and

probably in August (Bran & Luebbe in Germany). some other trainings (LIMS and computer,

quality management) will be organized out of the project.

The laboratory is expected to be fully operational by October, but it is already able to process the leaves analyses. The third consultancy mission is scheduled in October 1999 (two weeks).

key words: laboratory, plant analysis, analytical equipment, emission spectrometry, atomic absorption , continuous flow colorimetry, potentiometry, elemental analysis.

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The first mission, in October 1995, included all the steps required to define the means to make the new PTAL laboratory operational.

The observance of the proposais made in 1995 with the agement of the World Bank led to a completed laboratory at the beginning of 1999.

The second mission of the consultancy contract is devoted to the installation and operationalization of the laboratory. The objectives were to check the compliance of the equipment with the specifications, to test the analytical equipment, and to make some suggestions future (operating equipment, training) to make the PTAL laboratory fully operational as soon as possible.

1. Building

1.1.Layouts

The layout of the ground floor and second floor (areas, facilities) complies with the initial definition except for some modifications occured in the lounge and office (information) at the entrance of the lab because of the third floor extension. For this reason the position of the stairs was modified, and some additionnai glass walls were installed to better manage the traffic of the external people. These modifications were decided with the agrement of the consultant as they have no effect on the analyses.

The need of a storage room is not required anymore as the leaves samples are stored only for three years (request of the lab customers). The leaves samples storage will take place in the grinding room. The use of the" sample storage" room is modified to be used as soil extraction room. Only extractions that do not require acids can be processed there.

1.2. Facilities 1.2.1. gas

The installation is completed, conform and operating.

1.2.2. electricity

lt would have been relevant to better distinguish the UPS plugs from the non-Ups ones (colour, model) to prevent any misuse of UPS.

1.2.3. water

The installation is completed. The pure and deionized water production is not yet fully operating, some resin cartridges are missing (the delivery is expected very soon). However the production of pure water is sufficient to do the analyses at this moment.

1.2.4. hoods and canopy

They are correctly installed and efficient. The fume aspirators at the bench level are efficient only close to the ducts. This efficiency is probably depending on the other extracting systems and the fresh air blowers in the room (air flow in the room).

1.2.5. security

• The fumes and fire detectors are installed and operating in each room and in the corridors.

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room (all the rooms excepts the offices). 1 do not recommand to have an automatic system to start the extinguishers in case of fire alert, except in the acetylene and propane tanks storage room. A wrong alert would damage or destroy the equipments.

The risk of fire is actually very low if the eletric equipment are switched off every evening.

NB : these observations concern only the Plant Tissue and Soil Analysis Laboratory and not the laboratories that would be installed on the third floor .

• Three showers are installed in the rooms where concentrated and hot acids are used. 1

suggest to dispose in the other rooms persona! eyewash stations (for example ref 06796-70 model, 97/98 Cole Parmer catalogue, p.1006).

• Medicine cabinets including some products to treat cuts, burns, .... (2 well identified and easy to reach on each floor) should aise be installed .

The main pending concern is the water leacks (in the mineralisation rooms on the second floor}. The roof waterproofness is not completed around the ducts. This must be corrected as soon as possible to avoid repeated damage of the ceiling and

eliminate risks of damage of equipment (ovens, furnaces}.

2. Delivery of the equipments

By comparison with the specifications (see Mission report of November, 1995), we can do the followig observations :

2.1. Analytical equipment Ref A.1.

Model Brand Type

ICP Varian Liberty Series Il

Specifications Delivered Conformity Comment Action

Spectrometer y y

RF generator y y

Software y y

Accessories

Water cooler unit y y

Autosampler y y Combined units

Diluter y y

Pressure y y (for argon &

regulators nitrogen)

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Ref A.2.

Atomic absorption Perkin Elmer Analyst 300

spectrometer

Spectrometer y y

Software y y

Accessories

Autosampler y N No operating To be replaced

Diluter ?

Hollow cathod y y

lamps

Pressure y y (for air &

regulators acetylene)

The installation is completed, the equipment is ready to operate manually. lt will be accepted as soon as the autosampler is installed.

Ref A.3.

Elemental analyser Perkin Elmer Series Il 2410 (N)

Analyser y y

Data handling y y PC, but no

(built-in PC or PC) software

Accessories

Balance 0.1 mg y y

Autosampler y y

Pressure y y (for 02, C02 &

regulators pneu matie

command)

Printer y y

Chemicals & y y

consummables for 1000 samples

The installation is completed. lt can be accepted, even if some tests are still necessary to improve the quality of the results.

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Ref A.4.

Continuous flow Brand & Luebbe Autoanalyser Il analyser

colorimeter and photometer

Autosampler y y

photometer y y

Colorimeter y y

Peristaltic pump y y

Cartridges (P, B, y y Not fully complying Change pump tubes to

NH4, S, Cl, N03) with the adjust concnetration

concentration range.

ranges.

Data handling y y Problem corrected

on May 14

Accessories

Pressure y y

regulators

This equipment is installed, but the photometer has not be fully tested. However, the whole equipment can be accepted

Ref A.5.

Potentiometric Radiometer TIM 900

titration system

Titrator y y Electrodes : y y 2 silver electrodes 2 reference electrodes 1 combined pH el. Burettes y y Accessories Autosampler y y Printer y y

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2.2. Other equipments

Ref A.6. to A.19.

Ref. nr Description Deliver. Conform. Comment Action

A.6 Grinder y y

A.7. Analytical balance (4) y y

A.8. Top-loading balance y y

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A.9. Muffle furnace (3) y N 1. No door swinging No more complying

down, ta deep model available. Can

2. One door be used after supplier

isolation ta installation

change.

A.10. Drying aven (4) y y

A.11. Hot-plate y y rounded plate inform the

when heated manufacturer

A.12. Bench-top centrifuge y N Max speed not contact the

reached. Not manufacturer for more

critical but needs a information. check by the

supplier.

A.13. Programmable diluter y y

(2) 10 & 25 ml

A.14. Water purification y _N _{Missing cartridges}

system (washing) (2) (should be

supplied with 2 sets of spare cartridges)

A..15. Water purification y N Missing cartridges

system (analytical 20K (should be

water) (6) supplied with 2

sets of spare cartridges)

A.16. Magnetic stirrer (10) y y

A.17. Wrist motion shaker y y

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A.18. Portable pH-meter N purchasing in

process

A.19. Test kit for y y Not all. Modified order

ammonium, nitrate, phosphate, potassium, chloride, sulfate

Ali these equipments can be accepted, but some information about the hot-plates and centrifuge should be asked ta correct the slight defects

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2.3. Computers

The initial report is dated November 1995, so the proposais are no longer valid. Updated computers (5, 1MB 300 GL) were delivered, ready to be connected to the lab network.No problem for the installation as local PC. The server is not yet delivered.

2.4. Glassware

&

minor equipments

Conform the requirements except :

• 146 silica dishes instead 150 (4 broken when delivered) • no 5000 ml volumetric flask (2 proposed)

• no pipetting apparatus (price exceeds the limit for equipment) • no Robinson pipette (particle size analysis of soil)

• 3 instead 5 crucible tongs

These lapses are of no consequence for the lab's operation.

2.5. Reagents

Conforms the requirements except :

• multi-element standard solution for ICP (to expensive proposai)

A multi-element solution will be prepared using mono-element standard solution. lt is possible to prepare in the lab these solutions and to calibrate them with supplied standard solutions to spare them.

3. Training

3.1. Situation

At the end of May '99, the training programm is schematically the following :

1.Equipment training

Objective Supplier/ completion Comment

Atomic absorption use Perkin-Elmer y

ICP setrometer use Varian y

Colorimeter use Brand & Luebbe N Not yet scheduled (Germany)

Elemental analyser Perkin-Elmer N Scheduled June 1999 (Malaysia)

2. Management and general training

Management CIRAD, France y April 1995

lmprovement & evolution (2 CIRAD, France N If accepted,

persans) October/November '99

3. Computer & lab software

Network management To be defined N PCA Computer service ? Data base management To be defined N See LIMS section

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3.2. Comment and proposais

As a priority, the training to Perkin-Elmer's and Bran & Luebbe's must be completed. The trained staff should intensively use the corresponding equipments before the trainings in order to get their maximum efficiency. They could submit the encountered difficulties or problems to the engineers of these companies.

Later (during the 2000 year), training about the use of the computer network and data base management should be organised, in cooperation with the computer service of PCA which should be involved in the installation of the data handling system.

As the project has to be closed by the end of December, all the operations have to be finished by the end of October, including the final consultancy mission ; so it is impossible to include now the training mission of the staff in France at CIRAD proposed in the Mission Report (November 1995). 1 propose to postpone this mission in 2000 ; the training service of CIRAD will search for financing it.

The content of this training will partially depend on the encountered problems during the progressive starting of the lab. lt would be devoted to the installation of maintenance and verification procedures of the equipment, the control quality and the future evolution of the analyses, specially the soil analyses.

4. Testing the equipment

The objective of the test is to check the repeatability of the measures and the accuracy of the results. The repeatability is determind by the relative standard deviation of repeated measurements. The accuracy, when the raw data of the calibration are available, gives a global standard deviation of the measurements. The results are shown in details in the annexed document.

4.1. ICP spectrometer

Test procedure: calibration with multi-element standard (Cu, Fe, Mn, Zn) and repeated measurements of the standard 1 and standard 3 as samples.

The main results are the following :

Sample Copper (mg/L) Iron (mg/L) Mangan (mg/L) Zinc (mg/L)

STD1 Value 0.200 2.000 1.000 0.500 Result 0.196 1.914 0.956 0.484 %RSD 1.34 1.26 1 .11 1.26 STD3 value 3.000 30.000 15.000 7.500 Result 2.970 29.399 14.679 7.265 %RSD 0.69 0.87 0.62 0.96

We did not observe any dift during the measurements. The repeatability is complying with the expectation.

As ail the detailed data of the calibration and measurements are available (intensity and individual results of the three replications for each measurement), it is possible to estimate the standard deviation of a result including the uncertainty of the calibration (non perfect linearity, uncertainty of the standard values) and the standard deviation of the measurement itself. The results are the following :

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Sample Copper (mg/L) Iron (mg/L) Mangan (mg/L) Zinc (mg/L) STD1 Value 0.200 2.000 1.000 0.500 Result 0.195 1.953 0.980 0.494 %RSD 13.39 11.85 16.97 19.49 STD2 Value 1.400 14.000 7.000 3.500 Result 1.371 14.277 7.197 3.612 %RSD 2.25 2.41 2.78 3.17 STD3 Value 3.000 30.000 15.000 7.500 Result 3.014 29.874 14.909 7.448 %RSD 1.63 1.82 1.97 2.07

These results show that in the operating range of concentration, the uncertainty of the results is about 2%. For the very low concentrations (case STD1), the theoretical

uncertainty is high (the results would not be accurate). They were got in routine analytical conditions without optimization of the analytical parameters, so the ICP spectrometer can be considered as fully operational.

4.2. Atomic absorption spectrometer

1 noticed the very good installation (gas delivery and gas purification) and the very good and practical training by the local supplier Dakila Trade Corporation.

The control of this equipment is completed, except the sampler that is still missing (end of May 1999).

The test was done by analysing 20 trials on the same sample, so the %RSD includes the uncertainty of the measurements and the mineralization. The mean absorbance is 0.3568 and the %RSD is 1.72% for Mg. This technique is used in the PTAL for 20 years and is well managed by the staff. This equipment is fully operational.

4.3. Elemental analyser

The first test was performed du ring the first operation of this equipment. After the calibration with EDTA, a sample is analysed 20 times. The sample weight was around 50 mg.

We observed a significant drift during this first run. The first result was 1.42 %, the twentieth 1.88% , the mean was 1.66% with a relative standard deviation of 7.16%. This drift is

regular, identical for the zero read (ZR) and the nitrogen read (NR). The result is

proportionnai to the difference NR-ZR, depending on the Kn calibration factor. As the drift is regular enough, it is possible to do a correction. ln this case, the standard deviation is only 3.74 %, the lower result 1.38%, the higher 1.56%. This result is not totally satisfactory. During the second test a recalibration was made after 5 measurements ; 10 samples of about 50 mg and then 10 samples of about 100 mg were analysed. The drift is again

observed considering the ZR values , but is less important than the one observed in the first test.

This equipment can't be considered as fully operational. As the result of the analysis of EDTA is correct, the origin of these poor results could be an incorrect calibration or an incomplete combustion or reduction of the leaf samples.

About the calibration, 1 suggest to check the linearity by analysing EDTA weigh samples of

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About the combustion, 1 suggest to optimize the combustion, as described in the PE brochure (4-43 untill 4.46 pages, and 5.29). A low repeatibility and baseline drift could be due to an insufficient oxydation of N during the combustion as a result of a tao low oxygen flow rate. Sorne quick tests are to be carried out to adjust the separation timing interval (see

brochure 5. 72, 5. 73).

TEST 1 TEST 2

Mean 1.664 Mean 1.402

%RSD 7.16 %RSD 7.44

Lower value 1.42 {n°1) Lower value 1.17{n°11)

Higher value 1.88 (n°2) Higher value 1.62 (n°20)

Drift correct. Calibration Mean %RSD

effect

Mean 1.491 N° 1-5 1.358 3.40

%RSD 3.74 N° 6-10 1.386 5.37

Lower value 1.38 N° 11-15 1.354 8.28

Higher value 1.56 N° 16-20 1.512 5.41

First ZR (first 60370 First ZR (first 69013

measure) measure)

Last ZR (33 th 69614 Last ZR (33 th 74014

measure) measure)

Drift per measure 280 Drift per 151

measure

lt should be interesting to do these tests as soon as possible to take the printouts to PE during the next training.

4.4. Continuous flow analyser Colorimeter

After some data transmission problems between the colorimeter and the computer, the

whole system is operating. However, the concentration ranges of the delivered cartridges

don't match the requirements for plant analysis, except for B and S (These ranges were

given as specifications). On the other hand, they will be adapted to the future soil analyses,

so I would suggest to accept this equipment and do the relevant modifications of the

manifolds required by the plant analysis as suggested by Bran & Luebbe (fax). Actually, total N will be analysed by EA.

The test was done with the NH4 cartridge with salicylate reaction. Calibration was done with

0, 5 and 10 mg/L N standards. The 5 ml/L standard was analysed as 17 samples and the 10

mg/L standard was analysed one time at the end of the batch.

STD 1 STD2

Expected value 5 mg/1 10 mg/1

Calibration 4.946 10.027

Mean value 4.913 10.004

%RSD 0.53 NA

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These results are very good and confirm the quality of this equipment.

No test was performed with the photometer. A damping element will be included by the supplier to produce a smoother signal. Apparently this part of the Bran & Luebbe equipment is operational.

4.5. Potentiometer

Only very quick tests were done, to adjust the programming to directly get the result in the

right unit(% Cl). lt was possible to check the good repeatibility of the results (results between 0.292 and 0.299 %). Ali the equipment, including the sampler, is operational.

5. Third floor extension

Considering the installation of the aflatoxin and microbiology laboratories on the third floor,

we have the following commentsO :

• Special attention has to be paid to security requirements because of the use of

flammable chemicals. So, according to the layout presented on May 27, we suggest to

move the stock room on the side of the building in the place of sample stock room and to

move the sample stock room grinder room and weighing room close to balance room. lt

is also suggested to line up the doors of the grinder room to make easier the emergency evacuation of the aflatoxin lab. For the same reason, the door of the food laboratory toward the hall way could be moved close to the waiting area.

• The lockers could be moved to the confort rooms to produce a lab room (for the coming

HPLC equipment for example).

• The construction of the third floor laboratory must have no consequence on the PTAL

activity ; it must not lead any works on the second floor.

• The size of the lift is not appropriate to the 10 m3 gas cylinders (nitrogen). lt is necessary to check if the suppliers are able to delivery the 3m3 cylinders. An other possibilty is to

buy agas generator (compresser and filtration system). An economic evaluation has to

be made.

• The traffic in the buidling has to be organized. If the main stairs is use to accees only the third floor and the emergency stairs for the use of the PTAL staff, the doors to access the stairs from any floor must be able to be opened with a security bar system.

• Because of the value of the equipment in the building, a security guard could be

appointed to check the access of the visiting people.

6. Conclusion

The construction of the laboratory is completed but the third floor extension has to be done without disturbance for the ground and second floor laboratories and the water leaks have to be fixed as soon as possible.

Even if some equipments are not fully complying with the initial specifications, the laboratory can be considered as operational and all the equipments have to be accepted. However, some information about the hot-plates and the centrifuge will be asked.

The tests of the ICP spectrometer, atomic absorption spectrometer, colorimeter and

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method and the combustion procedure have to be improved, with the help of the supplier and the manufacturer.

Two trainings, about the elemental analyser (Perkin-Elmer) and the colorimeter (Bran & Luebbe) will be completed by August 1999. The PTAL laboratory will be fully operational by October ..

The following step will be the installation of the data handling system, with the help of the computer specialists of PCA. Simultaneously, some quality assurance procedures will be progressively introduced (use, daily maintenance and verification of the analytical

equipment). Later, it will be possible to start some soil analyses and methodological studies. The final consultancy mission is scheduled for October 1999.

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ANNEXE

1. Estimation of standards errors and uncertainty.

Generally the linear calibration transforms intensity (ICP) or absorbance (AA,

colorimetry) into concentration using the equation

C=a*l+b

the regression calculation gives a and b with their standard deviation sa and sb, the

intensity I is also known with a standard deviation s₁that is calculated if we perform

some replicated measurements. The combination of standard deviation leads to the

standard deviation of C, sc:

i.e.

**Sc=sqr{(a*l)**

2

*[(s/a)2 +(s

1

/1)

2

]

+

(sb )

2}

This formula was used to compute the standard deviation of the results coming from the uncertainty of the calibration. lt is possible to take into account the uncertainty of the sample weight (W) and of the volume of the volumetric flask in wich the

mineralization solution is put. As the result R is R=C*V/W (with the appropriate units)

we have:

NB: if a=b+c, sa= sqr{ (sb )2 + (se )2 }

If a=b*c or a=b/ c, s)a=sqr{(s/b)2 _{+ (}_s_/_c_)2}

2. ICP results

Caracteristics of the calibration:

squared R2_:₀_.₉₉₉₇ slope :2.31 E-05 st.dev.: 2.50E-07 lntercept:-0.0243 st.dev.: 0.026 Cu calibration 2,5

c3

2

}1

,

s

_•- - + - -· + > -' - l - - - + - - · . - - + - -•

0 ,

:

~

,

-_... .. : ....

i----·- : --0 20000 40000 60000 80000 100000 120000 140000 intensity

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Fe calibration

30 ~ - ~ ~ - ~ - - - -₁ - ~ - -- -~ ----~ ₁ 25 i 1 1

r--r---+-_-_.,..,..c-.;--1

____

---+--

!

L ___

J

1 __

/_J

.

_.._,.,

-20 ~ ,

!

1 !~...c.·_···+1 _ _,lc----+--i

,-- _ l

__ -+-_

1 ...

-r

1_-t--1

- - t - - i ~5 1 1 .,.- I I

u.

1 1 '_ ..• · 1 1 : ::::: : ./j

1

1 1

E

Q?O r - ·

---+i

--~~t~·1·--i---r--

J---+---1

1--- . 1 5 _________

/rf~~

_l _ __l_ - - ~ _ _ _ 1 __ ... 1

!

I

i 1

o

.. ·

• !

1 1 I 1 - 1 1 ' 1 1 -5 ° - - - -- - - ' ·----'---;---'---l--0 100000 200000 300000 400000 500000

intensity

Mn calibration -2 .' -0 200000 400000 600000 800000 1000000 1200000

intensity

Caracteristics of the calibration: squared R2 _:₀_.₉₉₉₈ slope :6.31 E-05 st.dev.: 6.0?E-07 lntercept: -0.1042 st.dev.: 0.2299

Caracteristics of the calibration:

squared R2 : 0.9995 si ope : 1. 34E-05 st.dev.: 1.85E-07 1 ntercept: -0. 0841 st.dev.: 0.1654

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Zn calibration 7 8-, - - - - , - - - - r -- - - , - - - - ---,----, ---1---·'---+-i---~' _ _ _ l __ ~i-- -- -1 i I i 1 __ •. -1 r 1 1 i _/ 6 l- - - ' - - - + - - ' ---'-- - - ' - - - ---,--'-';,~: ,_· - - - 1 - - -1 1 / ' C

s

_____

----+,'

- -,---+---r.c+.r_··--,..i _______ __ Caracteristics of the calibration: 1 / 1 i squared R 2 : 0.9995 N !

J,,,,.-i

:::::4 - - - · - 1 slope :2.0SE-05

O> st.dev.: 3.034E-07

E3 _ 1 r-·· - 1 2 - -

-~1~ ....

1 ---

:----+:-

- -~ - - > - - - 1 • • 1 l i 1 - e - - - + - - - ; - i _ _ _ _ _,_i _ _ _ _ - t - - -1 lntercept: -0.0543 st.dev.: 0.09566 0 ... 0

-

·

1 100000 200000 intensity 1 1 300000 400000

We can notice that, even with a very good calibration (squared R close to 1 ), the relative standard deviation is about 1 %. For the intercept, the relative standard deviation is high (it is normal) and leads to uncertain results when they are to close to zero.

STD1

80000 i==~===·E=:='.~f-===ï'.===3L~ ~ ~E-~ ~l~:::f,=::~E===î=:J

70000 -l- + - - --i---+---t---+----+- ~'----+---+----1--1 ~

:::::

---~r==~:~::~=-

==~~=: __

_ J ____ ,,----! ---+---_----+----~ 40000 ,- - t - - - + - - - - + - - - + - - - - t -- t - - - + - - - + - - - + - - - - + -- i Q) 1 ... t - - + - - - + - - - -·- - - + - - - - t - - + - - - + - - - - + - - - t ---1 C 30000

--i-

+::==::::::::===~==:::+==:::1'.:::=:=::'.~==~====t=

===

=t=====t_j

20000 -+-- + - -- + - - - - + - - - + - - - - t -- t - - - + - - - + -- -t----+-- i 10000 -

---· - - -

~

-

---

~

...,

=

==-

==-io==~

aa=

=

•

-1 0 -~-1--- - , - - - + - --+-- - + - - - + - - - - , ~ - ~ - - - ~ 2 > 4 ) > 7 é l ₁₀ sample n°

The following graphs don't show any drift over a 30mn period.

-

_Cu

--

_Fe

-

Mn

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STD3 1200000 1 1000000

-Cu 800000

-~ en 600000 C 1 1 Fe Q)

-+-' C 400000 - Mn

-200000 Zn 0 11 12 13 14 15 16 17 18 19 20 sample n° 2. Atomic absorption

The software selected a non-linear calibration curve, with a correlation coefficient equal to 1:

Mg calibration (AA300)

-0.2 0 0,2 0,4 0,6 0,8

absorbance

No signifacant drift is detected. The samples are 20 different mineralizations of the

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0,4 1 1 0,39 1 i 1 0,38 i 1 i ! (1) 0,37 1 ₁ 1 ü 0,36 C: ~- / ' -ctl .0

_....

0,35 , 1 1 1 0 _0,34 (/) 1 .0 ctl 0,33 0,32 1 1 l 1 ₁ 1 0,31 0,3 _j__ _--W- !

1-- -

---+--

---1-+-

-i 1 1 1 ! ₁ ! 1 ; 1 ! 1 1 ...L v ,, ! 1 i j 1 ! 1 1 1 ! ! 1 1 1 1 i 1 1

-++--Mg analysis AA300 1 1 1 .._ 1 1 ! i 1

,~

--1/ /

,

' / 1

"

'

.

...

' 1 1 1 1 ! 1 0 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 sample n° 3. Elemental analyser.

The software delivered the ZR values ("zero read") and NR ("nitrogen value"). The

values are a count number, the calibration gave the K value which is the count

number for 6 µg N. The N concentration of a sample is:

%N= (NR-ZR-BLK)/(1 O*K*W) where W is the sample weight in mg, BLK the count number of the blank.

The following graphs show the drift of all these values during two experiments. ln the

second one, a new calibration was done every 5 samples.

The correlation between the result and the position of the sample is significant (R2=0.781):

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EA 2410 test

2 1 75000 1,9 ; 1 1 1,8 1 1 / ... _, ₇₄₀₀₀ i 1 /

"

-

/ 1,7 - 1 ! _' .... / "O 1,6 -' ... / / ₇₃₀₀₀ rn 1 ii ~ /

-

_"-

-

_Q) 1,5

· ~

' IJ --;-- / ' / ' L... '' // ' / 1.4 '- / ₇₂₀₀₀_Z

z

/ '

•

1,3 ! 1

-~ 1 "O 0 _1,2_- ₇₁₀₀₀ rn ! Q) 1,1 - 1 1 L... ; 1 - 70000 0 L... ·-j ! 1 _Q) 0,9 1 1 N 0,8 ' i ₆₉₀₀₀ - - 1 - 1 0,7 - 1 1 1 0,6 1 1 ₆₈₀₀₀

1001 1002 1003 1004 1005 1006 1ob, 1000 1009 ID10 !011 1012 1013 101• 1015 I016 I017 1o'18 1019 1o'20

samples

- rawdata

-

drift corrected - - -- zero read N read

This graph shows the drift of all the type of samples analysed (calibration, blank, samples with different sample weight) during the second test.

en

...

C ::::, 0 ü EA 2410 2nd test 100000 -+-+l---+!-+-+--+--+--+---+---+---+-1 --l---l---+---+--!l----l----l---+-+-+-+--+'l--+---+---+---+---+--'+-'--1---1----+---1---+-1 1 - j E'1 1 1 95000 -+-+-+!---+1_.,_-+--[+--+--e+--+--t--1 ...,...,--,--+--+--+--+--+--+----+---+--+--l +--+--+--t--t--t---,--t--t--t-t -t-+--!',; --+-1 --+---+---+--+--+--t_J.i--+--+--!·--+--+-+--+--+--+--i--i+ +-+--+--+-+---+--+--+--+--+--i-1

90000 -+-+-+---+-+--+--+--+--+--+--+---+----+---+--+--+--+--+--+--t---t--+--+--+--+--+--+--t--t--t---,--t--t--t-t i i 1 i

l

...

~ - · -: -t---+--t--t--t--t--t--;i,·

--1

~-+-+-...,+__,-±,-+-,+.-... ...,.=r-H 80000

"J

i 1

1 -l

i i 1 1

i

1 i I i 85000 75000 70000 55000 -'-+--!i---+l-+-+---+---;l---+-+-+-1 ---+--+-+-+-t--!---+-+-+--+---+---t-1-+-I -+--+---+-+-+-+--r-t---+-+-' e K elK elK BLK cAl.... ,CO, tD03 1005 1006 1008 1010 1011 1013 1015 I016 1018 1020

BLK CAl1 CAL2 CAL3 CALS 1002 1004 CAL6 1007 1009 CAL7 1012 1014 CAL8 1017 1019

sample

- ZeroRead :a: NR counts (50 mg) -œ-- Calib.

:a: BLK - NR counts (100 mg)

(22)

2 ₁ ₁ 1,9 1 1 1,8 - 1 ! 1 1 1,7 i i 1 1 1,6 1 1

z

₁_,₅ -;:!2. 0 1,4 i -1 i 1 ! 1 -i

--..

1,3 _-_--_-·-- ' - 1 1 1 'i- 1/ 1,2 1 1 1 ! 1, 1 1 ! 1 1 1 1 1 I/ EA 2410 2nd test 1 1 \ 1 ; / \

,,

/ V I

-..

J ..

_,,.

1 L..,.,' 1 1 1 Il /i\ i / ,I ,; \ ,(

--

,

1 1 1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

samples

4. Colorimeter calibration 2 1--·-··;--,-·-f-c·•!-•··---' 1 -0 JE-· - - - ~ - - - ~ - ~ - - ~ 0 2 3 4 5 6 7 8 9 10 concentration mg/1

The calibration for NH4 is perfectly linear

(23)

5 4,95 4,9 ~ 4,85 I

z

4,8

z

4,75 :::::: 47 0) '

E

4,65 4,6 4,55 4,5 -0

'

"'l 1~ /

·-1 5

•

/ NH4 reproducibility "-

-\1/ 1 10

sample n°

-1 15

The drift is not significant (R2=0.286) and negligible.

-

--

measures

drift

(24)

·n AD-DIST