pt multi-mycotoxin coda-cerva 2017 final report …...coda-cerva 2017 multimycotoxin pt final report...

Central office Agrochemical Operational Direction: Experimental centre

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website :

http://www.coda-cerva.be

+32 (0)2 379 06 64 (dispatching)

CODA-CERVA

Belgian National Reference Laboratory

for

Mycotoxins in Food and Feed

Report on the 2017 Multimycotoxin Proficiency Test:

Determining 22 mycotoxins

in maize flour

Final report

CODA-CERVA 2017 multimycotoxin PT Final report

Contents

1 SUMMARY .............................................................................................................. 4

2 TIME FRAME, MATERIAL AND INSTRUCTIONS TO PARTICIPANTS ..... 4

3 ASSIGNED VALUES .............................................................................................. 5

4 SCORES AND EVALUATION CRITERIA .......................................................... 7

5 DETAILED RESULTS ........................................................................................ 11

6 DISCUSSION AND CONCLUSION .................................................................. 37

7 BIBLIOGRAPHY ................................................................................................. 38

8 ANNEXES ............................................................................................................ 39

8.1 Annex 1: Invitation letter to the laboratories ............................................................................................. 39

8.2 Annex 2: PT registration form................................................................................................................... 40

8.3 Annex 3: Instructions to the participants .................................................................................................. 40

8.4 Annex 4: Receipt form .............................................................................................................................. 41

8.5 Annex 5: Report form ................................................................................................................................ 41

8.6 Annex 6: List of the participating laboratories .......................................................................................... 43

8.7 Annex 7: Stability ...................................................................................................................................... 44

8.8 Annex 7: Homogeneity ............................................................................................................................. 44

8.9 Annex 8: Differences between the draft report and the final report .......................................................... 47

Table 1: Summary of the statistical parameters per analyte................................................................................................................ 8

Table 2: Overview of z and ζ scores per participant ........................................................................................................................... 9

Table 3: Overview of z and ζ scores continued ................................................................................................................................ 10

Table 4: AfB1........................................................................................................................................................................................... 12

Table 5: AfB2........................................................................................................................................................................................... 13

Table 6: AfG1 .......................................................................................................................................................................................... 14

Table 7: AfG2 .......................................................................................................................................................................................... 15

Table 8: Sum aflatoxins (Aftot) ............................................................................................................................................................ 16

Table 9: DON ......................................................................................................................................................................................... 17

Table 10: FB1 .......................................................................................................................................................................................... 18

Table 11: FB2 .......................................................................................................................................................................................... 19

Table 12: Sum of FB1 and FB2 ............................................................................................................................................................ 20


Table 13: FB3 .......................................................................................................................................................................................... 21

Table 14: ZEN ........................................................................................................................................................................................ 22

Table 15: T2 ............................................................................................................................................................................................. 23

Table 16: HT2 ......................................................................................................................................................................................... 24

Table 17: Sum of T2 and HT2 ............................................................................................................................................................. 25

Table 18: OTA ........................................................................................................................................................................................ 26

Table 19: NIV .......................................................................................................................................................................................... 27

Table 20: BEA ......................................................................................................................................................................................... 28

Table 21: EnnA ....................................................................................................................................................................................... 29

Table 22: EnnA1 ..................................................................................................................................................................................... 30

Table 23: EnnB ....................................................................................................................................................................................... 31

Table 24: EnnB1 ..................................................................................................................................................................................... 32

Table 25: FusX ........................................................................................................................................................................................ 33

Table 26: CIT ........................................................................................................................................................................................... 34

Table 27: 3-acetyl-deoxynivalenol (3AcDON) .................................................................................................................................. 35

Table 28: 15-acetyl-deoxynivalenol (15AcDON) .............................................................................................................................. 36

Table 29: Homogeneity .......................................................................................................................................................................... 46


1 Summary

The main objective of this proficiency test (PT) is to provide interested laboratories with an opportunity to test their

multi-mycotoxin methods on 22 mycotoxins at the same time on maize (corn) flour and to compare their interlaboratory

results.

The PT allowed the determination of the following 22 mycotoxins: aflatoxin B1 (AfB1), aflatoxin B2 (AfB2), aflatoxin

G1 (AfG1), aflatoxin G2 (AfG2), ochratoxin A (OTA), fumonisin B1 (FB1), fumonisin B1 (FB2), fumonisin B3 (FB3),

zearalenone (ZEN), deoxynivalenol (DON), T2-toxin (T2), HT2-toxin (HT2), enniatin A (EnnA), enniatin A1 (EnnA1),

enniatin B (EnnB), enniatin B1 (EnnB1), beauvericin (BEA), 3-acetyl-deoxynivalenol (3AcDON), 15-acetyl-

deoxynivalenol (15-AcDON), citrinin (CIT), fusarenone-X (FusX) and nivalenol (NIV). In addition, three sums of

mycotoxins were tested, respectively: the sum of FB1 and FB2, the aflatoxins and the sum of T2 & HT2.

In total 30 participants were accounted for. Participants were invited to report the mean value and measurement

uncertainty of their results. The assigned values (xa) and their uncertainties (u(xa)) were determined as the consensus of

participants’ results. Standard deviations for proficiency assessment were calculated using the modified Horwitz equation.

2 Time frame, material and instructions to participants

The main objective of the PT is to provide interested laboratories with an opportunity to test their multi-mycotoxin

methods on an all-in-one material with 22 mycotoxins and to compare their results with those of other laboratories. The

use of LC-MS/MS multi-mycotoxin methods, although not strictly required, is highly recommended. For the Official

Control Laboratories (OCL) approved by FASFC (the Belgian Federal Agency for the Safety of the Food Chain),

participation is mandatory for all the analytes for which they are approved, and recommended for the other analytes

insofar as their methods allow it. Other participants are of course free to select the analytes they wish to report for. The

amount of material is ca. 55 g per sample, and the participants were asked to report the results of the extraction and

analysis of 2 subsamples. They were asked to report the duplicate and averaged results in µg/kg and an estimate of their

measurement uncertainty (MU(k=2)) either in µg/kg or in %.


The time schedule is as follows:

- Opening of registration : - Monday 29/05/2017

- Deadline for registration : - Friday 16/06/2017

- Deadline for shipping of samples : - Wednesday 28/06/2017

- Deadline for submitting the results : - Monday 04/09/2017

- Deadline for draft report - Friday 20/10/2017

- Deadline for participants' reactions to the draft report : - Monday 20/11/2017

- Deadline for final report : - Friday 22/12/2017

3 Assigned values

The assigned values for the different toxins in the samples were determined as the consensus of all the participants’

results. The major advantages of consensus values are the straightforward calculation and the fact that none of the

participants is accorded a higher status. The disadvantages are that the consensus values are not independent of the

participant’s results and, especially with a low number of participants, that the uncertainty on the consensus (identified as

the standard error) may be high and the information content of the z-scores will be correspondingly reduced. However,

the IUPAC guide of 2010 on the selection and use of proficiency testing schemes for a limited number of participants

states that if the standard uncertainty of the assigned value u(xa) is insignificant in comparison to the fit-for-intended-use

target standard deviation σp (u(xa)2 <0.1* σp

2), then z-scores can be calculated in a small scheme in the same matter as

recommended in IUPAC 2006 for a large scheme. A minimum of eight quantified results is required to calculate z- and ζ-

scores (eight is the minimum number required to create a Kernel density distribution).

The robust statistic approach is a convenient modern method of handling results when they are expected to follow a

near-normal distribution and it is suspected that they include a small proportion of outliers. There are many different

robust estimators of mean and standard deviation. The median and MAD (median absolute difference) were chosen here

as robust estimators.


The modified Horwitz equation was used to establish the standard deviation for proficiency testing (σp). It is an

exponential relationship between the variability of chemical measurements and concentration. The Horwitz value is

widely recognized as a fitness-for-purpose criterion in proficiency testing.

For the analytes for which the kernel density plots showed a convincing central tendency and the HorRat value was

satisfactory (see Scheme 1) the MedianRef was assigned as ‘consensus’ or ‘reference’ value:

Vass = MedianRef

Scheme 1 : Steps followed to calculate the assigned value

a) The median of all the (averaged) uncensored results (MEDIAN) is calculated.

b) Results that were identifiable invalid or extreme outliers, identified via Grubbs outliers’ algorithm at a

significance level of 0.05, were excluded.

c) The medians of the remaining sets of results (‘reference’ sets) are calculated (MedianRef).

d) The median absolute differences of the remaining sets of results are calculated (MADref).

e) The robust standard deviations are calculated as σ(hat)rob = 1.4826 MADref.

f) The uncertainties on the MedianRef (with coverage factor k = 1) are calculated as: uref = σ(hat)rob /√nref

g) The “standard deviations for proficiency assessment" σpHor (improved) are calculated from the MedianRef,

using the Horwitz-Thompson equation.

h) A visual presentation of the remaining results was examined. It was checked whether the distribution

was apparently unimodal and roughly symmetric. If so Þ i); else Þ j).

i) If σ(hat)rob was less than about 1.2 σpHor(improved), then MedianRef was used as the assigned value Vass and

σ(hat)rob /√nref as its standard uncertainty u(xa).

j) A Kernel density estimate of the distribution was made using normal kernels with a bandwith h of 0.75

σpHor(improved). If this resulted in a unimodal and roughly symmetric kernel density, and the mode

and median were nearly coincident, then MedianRef was used as the assigned value Vass and σ(hat)rob

/√nref as its standard uncertainty; else Þ k).

k) If the minor mode could be safely attributed to an outlying result, then MedianRef was still used as the

assigned value Vass and σ(hat)rob /√nref as its standard uncertainty; else no consensus value could be

derived.


4 Scores and evaluation criteria

Individual laboratory performances are expressed in terms of z-scores and ζ-scores in accordance with ISO 135283 and

the International Harmonised Protocol.

Horσ

Vx

p

asslab -=z

)(xu)(xu

Vxζ

lab

2

a

2

asslab

+

-=

where:

· xlab is the mean of the individual measurement results as reported by the participant

· Vass is the assigned value

· σpHor (improved) is the standard deviation for proficiency assessment

· u(xa) is the standard uncertainty for the assigned value

· u(xlab) is the reported standard uncertainty on the reported value xlab.

The z-score compares the participant's deviation from the reference value with the standard deviation accepted for the

proficiency test.

The z-score can be interpreted as:

|z| ≤ 2 : satisfactory result

2 < |z| ≤ 3 : questionable result

|z| > 3 : unsatisfactory result

The ζ-score states if the laboratory result agrees with the assigned value within the uncertainty claimed by this laboratory.

The interpretation of the ζ-score is similar to the interpretation of the z-score.

| ζ | ≤ 2 : satisfactory result

2 < | ζ | ≤ 3 : questionable result

| ζ | > 3 : unsatisfactory result


Table 1: Summary of the statistical parameters per analyte

A f B 1 A f B 2 A f G1 A f G2 A f t o t OTA HT2

N 30 19 24 11 20 28 30

Mean 7.9 0 .8 3 .4 0 .4 12 .9 18 .2 135.1

STDEV 12 .3 1.1 8 .6 0 .4 25.4 7.8 52 .8

Med ian 6 .2 0 .4 1.4 0 .3 7.5 17.2 127.0

Med ian Ref 5.6 1.3

σ (hat)r ob 1.4 0 .3

σp Ho r (improved ) 1.2 0 .3

Va s s 5.6 1.3

us t a nda r d (u(xa)) 0 .2 0 .1

T2 S um HT2 +T2 D ON ZEN F B 1 F B 2 S um F B 1+F B 2

N 30 24 29 29 30 29 23

Mean 496 .2 636 .8 797.9 1986 .7 8288 .6 1315.9 10209 .3

STDEV 141.1 155.4 206 .8 479 .6 2791.5 516 .4 3016 .9

Med ian 555.7 698 .2 815.0 2059 .5 7900 .0 1295.0 10037.0

Med ian Ref 511.4 689 .0 812 .1

σ (hat)r ob 92 .0 68 .9 158 .9

σp Ho r (improved ) 90 .5 116 .6 134 .0

Va s s 511.4 689 .0 812 .1

us t a nda r d (u(xa)) 15.8 13 .3 28 .1

F B 3 N IV C IT EnnA EnnA 1 EnnB EnnB 1

N 13 13 7 3 5 8 6

Mean 2701.5 158 .1 12 .8 2 .6 25.1 598 .0 132 .8

STDEV 885.0 58 .8 13 .9 3 .8 14 .9 219 .4 33 .8

Med ian 2752 .0 150 .0 6 .0 0 .6 18 .7 579 .9 122 .5

Med ian Ref

σ (hat)r ob

σp Ho r (improved )

Va s s

us t a nda r d (u(xa))

B EA F us X 3 A c D ON 15A c D ON

N 8 10 6 8

Mean 312 .4 275.8 32 .0 70 .6

STDEV 65.2 58 .1 13 .7 34 .4

Med ian 312 .9 276 .1 30 .1 57.6

Med ian Ref

σ (hat)r ob


Va s s

us t a nda r d (u(xa))


Table 2: Overview of z and ζ scores per participant

AfB1 AfB2 AfG1 AfG2 Aftot OTA HT2

z-score zeta-score z-score zeta-score z-score zeta-score z-score zeta-score z-score zeta-score z-score zeta-score z-score zeta-score

L1 1.1 1.8 2.4 3.1

L2 1.1 2.7 1.7 2.5

L3 0.9 1.2 2.0 2.9

L4 0.5 0.4 -0.2 -0.2

L5 -2.3

L6 -1.4 -3.3 -23.9

L7 -0.8 -1.1 0.6 0.0

L8 4.3 2.6 17.5 4.0

L9 -1.1 -1.5 0.1 0.1

L11 -1.0 -1.5 0.2 0.2

L12 -0.1 -0.1 -0.1 -0.1

L13 0.5 2.3

L14 -2.9 -11.8 -2.4 -6.0

L15 -0.8 -1.2 0.4 0.0

L16 -1.2 -1.9 0.7 0.7

L17 1.7 1.3 0.8 0.6

L18 0.6 0.8 1.8 0.0

L19 -2.5 -4.4 -0.7 -0.7

L20 54.6 7.4 153.9 7.8

L21 0.8 2.7 3.6 4.4

L22 2.1 1.2

L23 0.7 1.9 0.8 1.9

L24 -2.0 -5.5 -1.6 -3.7

L25 0.9

L26 0.0 0.0 -1.8 -3.9

L27 0.8 3.8

L28 -0.3 -0.4 -23.9

L29 1.3 0.9 5.0 2.1

L30 0.2 0.3 0.5 1.0

L32 0.9 0.8 0.7 0.6

T2 Sum HT2+T2 DON ZEN FB1 FB2 Sum FB1+FB2


L1 0.4 1.4 -0.1 -0.2 0.7 0.8

L2 -1.0 -3.3 0.1 0.1

L3 0.9 2.5 0.2 0.4 0.0 0.0

L4 -0.4 -0.3 -0.3 -0.2

L5 1.2 1.1

L6 -0.2 -0.5 -0.8 -1.3 -2.0 -3.4

L7 -0.2 -0.1 -0.4 -0.4 0.4 0.7

L8 -2.1 -3.1 -2.3 -2.5 -0.9 -1.1

L9 1.1 0.8 0.3 0.3 2.0 1.2

L11 1.6 1.8 1.2 1.4 0.1 0.2

L12 0.2 0.1 0.0 0.0 -0.2 -0.2

L13 0.9 4.4 0.2 -0.7 -2.8

L14 -1.4 -2.7 -2.0 -3.5 -4.4 -11.9

L15 1.0 0.8 0.5 0.4 2.0 1.9

L16 -0.9 -1.4 -1.0

L17 -3.3 -8.4 1.3 1.4

L18 1.1 0.8 0.4 0.3 0.0 0.0

L19 -0.4 -0.3

L20 -3.7 -11.1 -4.2 -3.4 -13.9

L21 0.5 2.7 0.1 0.5 1.6 5.8

L22 0.8 0.5 0.2 0.1 -0.4 -0.3

L23 0.9 2.0 0.4 0.9 1.5 3.7

L24 -1.3 -2.2 -1.6 -2.9 -0.1 -0.1

L25 2.0 1.5 1.5

L26 -2.2 -2.6 -2.5 -2.6 -2.8 -10.1

L27 0.9 -1.0

L28 -3.7 -11.4 -1.4 -1.5 0.5 0.8

L29 0.6 0.6 0.2 0.2 0.1 0.1

L30 0.6 1.4 0.1 1.1 1.8

L32 1.0 1.3 0.8 0.7 0.0 0.0


Table 3: Overview of z and ζ scores continued

FB3 NIV CIT EnnA EnnA1 EnnB EnnB1


L1

L2

L3

L4

L5

L6

L7

L8

L9

L11

L12

L13

L14

L15

L16

L17

L18

L19

L20

L21

L22

L23

L24

L25

L26

L27

L28

L29

L30

L32

BEA FusX 3AcDON 15AcDON

z-score zeta-score z-score zeta-score z-score zeta-score z-score zeta-score

L1

L2

L3

L4

L5

L6

L7

L8

L9

L11

L12

L13

L14

L15

L16

L17

L18

L19

L20

L21

L22

L23

L24

L25

L26

L27

L28

L29

L30

L32


5 Detailed Results

Tables 4-28 contain for each toxin or sum of toxins, the following information:

· The duplicate and average results (in µg/kg)

· The measurement uncertainties (expressed in %, since the participants had the choice of reporting in either

µg/kg or %, the value provided in in µg/kg was recalculated as %)

· The accreditation status

· The z- and ζ-scores

· The results of the statistical calculations

In these tables:

· The z- and ζ-scores are highlighted in red if: z or ζ >2

· Apparent outliers are indicated

Each page comprises the following plots:

· The kernel density plots after removal of outliers

· The results in µg/kg

· The MU as reported

· The z- and ζ-scores


Table 4: AfB1

Lab number LOQ ULOQ Result 1 Result 2 Average Accred ited Uncertainty (%) z-sco re zeta-sco re Outlier

L1 0 .2 7.4 6 .4 6 .9 y 21 1.1 1.8

L2 0 .5 50 6 .2 7.6 6 .9 Y 13 1.1 2 .7

L3 0 .5 6 .6 6 .6 6 .6 Y 25 0 .9 1.2

L4 6 .8 5.6 6 .2 Y 46 0 .5 0 .4

L5 13 .2 3 .9 1.7 2 .8 N - 2 .3

L6 2 .0 4 000 2 .9 4 .9 3 .9 Y 23 -1.4 - 3 .3

L7 0 .5 4 .9 4 .2 4 .5 Y 41 -0 .8 -1.1

L8 6 .8 60 12 .0 9 .7 10 .9 N 37 4 .3 2 .6

L9 0 .1 4 .2 4 .2 4 .2 Y 40 -1.1 -1.5

L11 0 .1 3 .9 4 .8 4 .4 Y 34 -1.0 -1.5

L12 0 .5 6 .0 4 .9 5.5 Y 31 -0 .1 -0 .1

L13 0 .3 6 .1 6 .4 6 .2 N 5 0 .5 2 .3

L14 1.0 2 .0 2 .0 2 .0 Y 18 - 2 .9 - 11.8

L15 0 .5 20 4 .8 4 .3 4 .6 Y 36 -0 .8 -1.2

L16 0 .2 4 .0 4 .2 4 .1 Y 35 -1.2 -1.9

L17 2 .0 50 7.6 7.6 7.6 N 40 1.7 1.3

L18 1.0 6 .0 6 .5 6 .3 Y 27 0 .6 0 .8

L19 0 .5 10 2 .4 2 .7 2 .6 Y 50 - 2 .5 - 4 .4

L20 1.0 64 .5 80 .0 72 .3 N 25 54 .6 7 .4 Y

L21 0 .4 6 .1 6 .9 6 .5 N 8 0 .8 2 .7

L22 2 .0 9 .3 6 .9 8 .1 Y 50 2 .1 1.2

L23 0 .5 6 .5 6 .3 6 .4 Y 12 0 .7 1.9

L24 0 .2 3 .0 3 .2 3 .1 N 25 -2 .0 - 5 .5

L25 0 .5 1000 7.0 6 .3 6 .7 N 0 .9

L26 0 .5 5.7 5.4 5.6 Y 30 0 .0 0 .0

L27 1.0 6 .6 6 .4 6 .5 N 0 .8

L28 2 .5 5.7 4 .7 5.2 Y 31 -0 .3 -0 .4

L29 10 .0 6 00 6 .9 7.4 7.1 Y 50 1.3 0 .9

L30 0 .3 100 5.1 6 .4 5.8 Y 21 0 .2 0 .3

L32 1.0 6 .9 6 .3 6 .6 Y 40 0 .9 0 .8

N 30

Mean 7.9

STDEV 12 .3

Med ian 6 .2

Med ian Ref 5.6

σ (hat)r ob 1.4

σp Ho r (improved ) 1.2

V a s s 5 .6

u s t a n d a r d ( u( x a ) ) 0 .2

AfB

1

-13-12-11-10-9-8-7-6-5-4-3-2-10123456

Sco

re

Lab number

z-scor e

zeta-s core

0

2

4

6

8

10

12

14

16

µg k

g-1

Lab number

0

0 .05

0 .1

0 .15

0 .2

0 .25

-5 0 5 1 0 1 5

Kernel Density Plot


Table 5: AfB2


L1 0 .1 0 .7 0 .7 0 .7 Y 20

L2 0 .1 10 0 .4 0 .4 0 .4 Y 45

L3 0 .5 0 .5 0 .5 0 .5 Y 20

L4 1.0 1.0 1.0 1.0 40

L5 16 .8 N

L6 2 .0 4 000 Y 26

L7 0 .5 Y 31

L8 1.5 60 3 .0 2 .9 3 .0 N 36

L9 0 .1 0 .2 0 .2 0 .2 Y 40

L11 0 .1 0 .3 0 .3 0 .3 Y 30

L12 0 .5 Y

L13 0 .3 0 .3 0 .3 0 .3 N 5

L14 1.5 0 .1 0 .1 0 .1 Y 32

L15 0 .5 20 Y 31

L16 0 .2 0 .3 0 .3 0 .3 Y 34

L17 2 .0 50 0 .5 0 .6 0 .5 N 50

L18 1.0 Y 25

L19

L20 1.0 3 .5 5.8 4 .6 N 25

L21 0 .4 0 .3 0 .4 0 .3 N 3

L22

L23 0 .5 0 .4 0 .4 0 .4 Y 12

L24 0 .2 0 .2 0 .2 0 .2 N 50

L25

L26 1.0 0 .6 0 .0 0 .3 Y 15

L27 1.0 N

L28 2 .5 Y 16

L29 4 .0 2 40 0 .7 0 .6 0 .6 Y 50

L30 0 .3 2 5 0 .5 0 .4 0 .5 Y 21

L32 1.0 0 .5 0 .6 0 .6 32

N 19

Mean 0 .8

STDEV 1.1

Med ian 0 .4

Med ian Ref

σ (hat)r ob


V a s s

u s t a n d a r d ( u( x a ) )

AfB

2

-4

-3

-2

-1

0

1

2

3

4

Sco

re

Lab number

z-scor e

zeta-s core

0

1

2

3

4

5

6

7

µg k

g-1

Lab number

0

0 .5

1

1 .5

2

2 .5

3

-0.5 0 0 .5 1 1 .5

Kernel Density Plot


Table 6: AfG1


L1 0 .2 1.9 1.9 1.9 Y 21 2 .4 3 .1 y

L2 0 .5 50 1.5 1.9 1.7 Y 21 1.7 2 .5

L3 0 .5 1.8 1.8 1.8 Y 20 2 .0 2 .9

L4 1.4 1.0 1.2 Y 40 -0 .2 -0 .2

L5 24 .5 N

L6 2 .0 4 000 Y 25 - 2 3 .9

L7 1.0 1.1 1.8 1.4 Y 28 0 .6

L8 1.9 60 6 .3 5.8 6 .1 N 39 17 .5 4 .0 y

L9 0 .1 1.3 1.3 1.3 Y 40 0 .1 0 .1

L11 0 .1 1.3 1.3 1.3 Y 35 0 .2 0 .2

L12 0 .5 1.2 1.2 1.2 Y 43 -0 .1 -0 .1

L13 0 .3 N

L14 1.5 0 .6 0 .6 0 .6 Y 32 - 2 .4 - 6 .0 y

L15 0 .5 20 1.3 1.4 1.4 Y 32 0 .4

L16 0 .2 1.5 1.4 1.4 Y 36 0 .7 0 .7

L17 2 .0 50 1.5 1.4 1.5 N 50 0 .8 0 .6

L18 1.0 1.7 1.8 1.8 Y 29 1.8

L19 0 .5 50 1.0 1.1 1.1 Y 52 -0 .7 -0 .7

L20 2 .0 36 .3 50 .9 43 .6 N 25 153 .9 7 .8 Y

L21 0 .4 1.9 2 .6 2 .2 N 20 3 .6 4 .4 y

L22

L23 0 .5 1.5 1.4 1.5 Y 13 0 .8 1.9

L24 0 .2 0 .8 0 .9 0 .8 N 25 -1.6 - 3 .7

L25

L26 1.0 0 .4 1.1 0 .8 Y 31 -1.8 - 3 .9

L27 1.0 2 .3 2 .3 2 .3 N 3 .8 y

L28 2 .5 Y 19 - 2 3 .9

L29 10 .0 6 00 2 .6 2 .6 2 .6 Y 50 5 .0 2 .1 y

L30 0 .3 100 1.1 1.7 1.4 y 21 0 .5 1.0

L32 1.0 1.2 1.7 1.5 Y 45 0 .7 0 .6

N 24

Mean 3 .4

STDEV 8.6

Med ian 1.4

Med ian Ref 1.3

σ (hat)r ob 0 .3

σp Ho r (improved ) 0 .3

V a s s 1.3

u s t a n d a r d ( u( x a ) ) 0 .1

AfG

1

-26-25-24-23-22-21-20-19-18-17-16-15-14-13-12-11-10-9-8-7-6-5-4-3-2-1012345

Sco

re

Lab number

z-scor e

zeta-s core

0

0.5

1

1.5

2

2.5

µg k

g-1

Lab number

0

0 .2

0 .4

0 .6

0 .8

1

1 .2

1 .4

0 0 .5 1 1 .5 2 2 .5 3

Kernel Density Plot


Table 7: AfG2


L1 0 .2 0 .0 0 .0 0 .0 Y 20

L2 0 .1 10

L3 0 .5 0 .3 0 .3 0 .3 Y 25

L4 1.0 1.0 1.0 1.0 Y 40

L5 19 .6 N

L6 5.0 4 000 Y 31

L7 0 .5 Y 54

L8 2 .4 80

L9 0 .1 0 .1 0 .1 0 .1 Y 40

L11 0 .1 0 .1 0 .1 0 .1 Y 30

L12 0 .5 0 .7 0 .8 0 .7 Y 40

L13 0 .6 N

L14 1.5 0 .0 0 .0 0 .0 Y 22

L15 0 .5 20 Y 33

L16 0 .3 Y 38

L17 2 .0 50 0 .6 0 .6 0 .6 N 50

L18 1.0 Y 29

L19

L20

L21 0 .4 N 7

L22

L23 0 .5 0 .4 0 .4 0 .4 Y 13

L24 0 .3 0 .2 0 .3 0 .2 N 100

L25

L26 1.0 Y 22

L27 1.0 N

L28 2 .5 Y 26

L29 16 .0 9 60 Y 50

L30 0 .6 2 5 y 21

L32 1.0 1.4 1.2 1.3 Y 36

N 11

Mean 0 .4

STDEV 0.4

Med ian 0 .3

Med ian Ref

σ (hat)r ob


V a s s


AfG

2

-4

-3

-2

-1

0

1

2

3

4

Sco

re

Lab number

z-scor e

zeta-s core

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

µg k

g-1

Lab number

0

0 .2

0 .4

0 .6

0 .8

1

1 .2

0 0 .2 0 .4 0 .6 0 .8 1 1 .2

Kernel Density Plot


Table 8: Sum aflatoxins (Aftot)


L1 0 .7 10 .0 9 .0 9 .5 Y 41

L2 1.2 120

L3 2 .0 9 .2 9 .2 9 .2 Y 45

L4

L5 N

L6 5.0 4 000

L7 2 .5 6 .0 5.9 5.9 Y 31

L8

L9 5.8 5.8 5.8 Y 40

L11 0 .4 5.5 6 .4 6 .0 Y 35

L12 0 .5 7.9 6 .9 7.4 Y 43

L13 1.5 7.7 8 .2 7.9 N

L14 5.5 2 .8 2 .7 2 .7 Y 53

L15 2 .0 80 6 .1 5.7 5.9 Y 30

L16 0 .9 5.8 5.9 5.8 Y 26

L17

L18 1.0 7.7 8 .3 8 .0 Y 29

L19

L20 104 .3 136 .7 120 .5 N Y

L21 8 .0 9 .4 8 .7 N 9

L22

L23 0 .5 8 .9 8 .5 8 .7 Y 12

L24 4 .0 4 .3 4 .1 N 25

L25

L26 2 .0 5.7 6 .5 6 .1 Y 25

L27 N

L28 10 .0 5.7 4 .7 5.2 Y 48

L29 4 .0 2 400 10 .2 10 .6 10 .4 Y 50

L30 6 .7 8 .5 7.6 n

L32 4 .0 10 .2 15.0 12 .6 Y 35

N 20

Mean 12 .9

STDEV 25.4

Med ian 7.5

Med ian Ref

σ (hat)r ob


V a s s


SU

M A

FL

A

-4

-3

-2

-1

0

1

2

3

4

Sco

re

Lab number

z-scor e

zeta-s core

0

2

4

6

8

10

12

14

16

18

µg k

g-1

Lab number

0

0 .05

0 .1

0 .15

0 .2

-5 0 5 1 0 1 5 2 0

Kernel Density Plot


Table 9: DON


L1 100 .0 921.2 881.2 901.2 Y 23 0 .7 0 .8

L2 10 .0 4 000 882 .0 763 .0 822 .5 Y 23 0 .1 0 .1

L3 50 .0 811.4 811.4 811.4 Y 15 0 .0 0 .0

L4 770 .0 770 .0 770 .0 Y 50 -0 .3 -0 .2

L5 65.6 960 .4 966 .7 963 .6 N 1.1

L6 100 .0 8 000 553 .0 535.0 544 .0 Y 27 -2 .0 - 3 .4

L7 10 .0 903 .7 838 .2 871.0 Y 18 0 .4 0 .7

L8 60 .6 4 000 679 .0 707.0 693 .0 N 29 -0 .9 -1.1

L9 20 .0 1080 .0 1080 .0 1080 .0 Y 40 2 .0 1.2

L11 50 .0 815.0 849 .0 832 .0 Y 23 0 .1 0 .2

L12 75.0 742 .0 835.0 788 .5 Y 32 -0 .2 -0 .2

L13 154 .0 748 .5 696 .8 722 .7 N 4 -0 .7 - 2 .8

L14 25.0 230 .0 210 .0 220 .0 Y 37 - 4 .4 - 11.9 Y

L15 50 .0 1750 998 .5 1148 .6 1073 .6 Y 25 2 .0 1.9

L16 10 .0 699 .0 652 .0 675.5 N -1.0

L17 200 .0 5000 1038 .0 948 .0 993 .0 N 25 1.3 1.4

L18 50 .0 832 .5 793 .0 812 .8 Y 27 0 .0 0 .0

L19

L20 0 .5 359 .2 342 .1 350 .6 N 10 - 3 .4 - 13 .9

L21 64 .0 1054 .0 991.0 1022 .5 N 4 1.6 5 .8

L22 362 .0 767.3 742 .2 754 .7 Y 50 -0 .4 -0 .3

L23 100 .0 981.9 1039 .4 1010 .7 Y 9 1.5 3 .7

L24 2 .0 793 .6 808 .6 801.1 N 25 -0 .1 -0 .1

L25 100 .0 10000 1022 .0 1012 .0 1017.0 N 1.5

L26 30 .0 487.8 390 .0 438 .9 Y 11 - 2 .8 - 10 .1

L27 30 .0 668 .0 678 .0 673 .0 N -1.0

L28 200 .0 790 .0 980 .0 885.0 Y 21 0 .5 0 .8

L29 80 .0 4 800 817.7 842 .0 829 .9 Y 30 0 .1 0 .1

L30 250 .0 10000 1110 .0 820 .0 965.0 y 17 1.1 1.8

L32 20 .0 920 .0 710 .0 815.0 Y 17 0 .0 0 .0

N 29

Mean 797.9

STDEV 206 .8

Med ian 815.0

Med ian Ref 812 .1

σ (hat)r ob 158 .9


V a s s 8 12 .1

u s t a n d a r d ( u( x a ) ) 2 8 .1

DO

N

-15-14-13-12-11-10-9-8-7-6-5-4-3-2-101234567

Sco

re

Lab number

z-scor e

zeta-s core

0

200

400

600

800

1000

1200

1400

1600

µg k

g-1

Lab number

0

0 .00 05

0 .00 1

0 .00 15

0 .00 2

0 .00 25

0 5 00 1 00 0 1 50 0

Kernel Density Plot


Table 10: FB1


L1 25.0 8579 .0 9881.0 9230 .0 Y 25

L2 10 .0 6 800 6540 .0 6180 .0 6360 .0 Y 10

L3 50 .0 8624 .0 8624 .0 8624 .0 Y 10

L4 8000 .0 7700 .0 7850 .0 Y 54

L5 86 .8 7620 .0 7773 .0 7696 .5 N

L6 20 .0 8 000 6526 .0 6566 .0 6546 .0 Y 39

L7 50 .0 6496 .6 5873 .6 6185.1 Y 62

L8 31.8 1200 7333 .0 7665.0 7499 .0 N 12

L9 20 .0 10400 .0 10400 .0 10400 .0 Y 40

L11 25.0 8002 .0 6542 .0 7272 .0 Y 26

L12 125.0 6990 .0 7569 .0 7279 .5 Y 36

L13 39 .5 6208 .0 6413 .0 6310 .5 N 5

L14 60 .0 16000 .0 15000 .0 15500 .0 Y 15

L15 25.0 2 000 9245.1 8913 .7 9079 .4 Y 39

L16 10 .0 12500 .0 10000 .0 11250 .0 N

L17 200 .0 5000 8822 .0 8720 .0 8771.0 N 20

L18 50 .0 5902 .7 7390 .1 6646 .4 Y 47

L19 20 .0 2 000 612 .0 599 .0 605.5 Y 46 Y

L20 2 .0 4368 .2 4719 .0 4543 .6 N 10

L21 40 .0 7849 .0 7657.0 7753 .0 N 5

L22 677.0 13057.7 10337.3 11697.5 Y 50

L23 25.0 9087.0 9246 .0 9166 .5 Y 16

L24 2 .0 9173 .0 9533 .0 9353 .0 N 25

L25 5.0 50000 9744 .0 10164 .0 9954 .0 N

L26 25.0 7579 .5 6553 .8 7066 .7 Y 70

L27 50 .0 8420 .0 8550 .0 8485.0 N

L28 100 .0 14000 .0 15000 .0 14500 .0 Y 27

L29 1000 .0 4 80 00 5660 .0 5708 .0 5684 .0 N 50

L30 25.0 10000 10500 .0 8300 .0 9400 .0 y 15

L32 20 .0 8300 .0 7600 .0 7950 .0 Y 35

N 30

Mean 8288 .6

STDEV 2791.5

Med ian 7900 .0

Med ian Ref

σ (hat)r ob


V a s s


FB

1

-4

-3

-2

-1

0

1

2

3

4

Sco

re

Lab number

z-scor e

zeta-s core

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

20000

µg k

g-1

Lab number

0

0 .00 00 5

0 .00 01

0 .00 01 5

0 .00 02

0 .00 02 5

0 5 00 0 1 00 00 1 50 00

Kernel Density Plot


Table 11: FB2


L1 40 .0 1322 .9 1290 .0 1306 .4 Y 21

L2 10 .0 2500 1092 .0 1050 .0 1071.0 Y 15

L3 10 .0 1414 .0 1414 .0 1414 .0 Y 10

L4 930 .0 960 .0 945.0 Y 68

L5 44 .7 1510 .0 1646 .0 1578 .0 N

L6 20 .0 8 000 1045.0 1099 .0 1072 .0 Y 26

L7 50 .0 1003 .0 1005.0 1004 .0 Y 72

L8 24 .4 1600 1264 .0 1288 .0 1276 .0 N 8

L9 20 .0 1400 .0 1400 .0 1400 .0 Y 40

L11 25.0 1782 .0 1698 .0 1740 .0 Y 28

L12 50 .0 1422 .0 1357.0 1389 .5 Y 46

L13 13 .8 789 .0 822 .8 805.9 N 2

L14 100 .0 3400 .0 3400 .0 3400 .0 Y 15 Y

L15 25.0 2 000 1622 .2 1657.6 1639 .9 Y 38

L16 10 .0 1420 .0 1170 .0 1295.0 N

L17 195.0 4875 1300 .0 1258 .0 1279 .0 N 30

L18 50 .0 823 .3 1204 .7 1014 .0 Y 47

L19 20 .0 2 000 472 .0 468 .0 470 .0 Y 45

L20 2 .0 786 .6 836 .2 811.4 N 10

L21 40 .0 1381.0 1389 .0 1385.0 N 4

L22 867.0 1939 .1 1824 .4 1881.8 Y 50

L23 25.0 1484 .0 1420 .0 1452 .0 Y 19

L24 2 .0 1488 .0 1504 .0 1496 .0 N 25

L25 5.0 50000 1523 .0 1427.0 1475.0 N

L26 25.0 1083 .6 807.3 945.5 Y 56

L27 50 .0 998 .0 1050 .0 1024 .0 N

L28 40 .0 1700 .0 1700 .0 1700 .0 Y 26

L29

L30 12 .5 5000 1100 .0 1000 .0 1050 .0 y 15

L32 20 .0 890 .0 790 .0 840 .0 Y 29

N 29

Mean 1315.9

STDEV 516 .4

Med ian 1295.0

Med ian Ref

σ (hat)r ob


V a s s


FB

2

-4

-3

-2

-1

0

1

2

3

4

Sco

re

Lab number

z-scor e

zeta-s core

0

500

1000

1500

2000

2500

3000

µg k

g-1

Lab number

0

0 .00 02

0 .00 04

0 .00 06

0 .00 08

0 .00 1

0 .00 12

0 5 00 1 00 0 1 50 0 2 00 0 2 50 0

Kernel Density Plot


Table 12: Sum of FB1 and FB2


L1 65.0 9902 .0 11170 .9 10536 .4 y 33

L2 20 .0 5000

L3 60 .0 10037.0 10037.0 10037.0 Y 15

L4

L5 N

L6 20 .0 8 000 7571.0 7665.0 7618 .0 Y 33

L7 100 .0 7499 .6 6878 .6 7189 .1 Y 67

L8 8597.0 8952 .0 8774 .5 N 9

L9 11800 .0 11800 .0 11800 .0 Y 40

L11 50 .0 9784 .0 8240 .0 9012 .0 Y 28

L12 125.0 8412 .0 8926 .0 8669 .0 Y 46

L13 53 .3 6997.2 7236 .2 7116 .7 N

L14 160 .0 19400 .0 18400 .0 18900 .0 Y 21 Y

L15 50 .0 4 000 10867.3 10571.3 10719 .3 Y 38

L16 20 .0 13900 .0 11200 .0 12550 .0 N

L17

L18 50 .0 6726 .0 8594 .8 7660 .4 Y 47

L19

L20 5154 .8 5555.2 5355.0 N

L21 9230 .0 9046 .0 9138 .0 N 4

L22 1540 .0 14996 .8 12161.7 13579 .3 Y 50

L23 25.0 10571.0 10666 .0 10618 .5 Y 17

L24 10661.0 11037.0 10849 .0 N 25

L25 11267.0 11591.0 11429 .0 N

L26 25.0 8663 .1 7361.1 8012 .1 Y 60

L27 N

L28 140 .0 16000 .0 16000 .0 16000 .0 Y 38

L29

L30 11600 .0 9300 .0 10450 .0 y 15

L32 40 .0 9200 .0 8400 .0 8800 .0 Y 30

N 23

Mean 10209 .3

STDEV 3016 .9

Med ian 10037.0

Med ian Ref

σ (hat)r ob


V a s s


SU

M F

B1

FB

2

-4

-3

-2

-1

0

1

2

3

4

Sco

re

Lab number

z-scor e

zeta-s core

0

5000

10000

15000

20000

25000

µg k

g-1

Lab number

0

0 .00 00 5

0 .00 01

0 .00 01 5

0 .00 02

0 5 00 0 1 00 00 1 50 00 2 00 00

Kernel Density Plot


Table 13: FB3


L1

L2 10 .0 2500 2614 .0 2370 .0 2492 .0 Y 11

L3 10 .0 2752 .0 2752 .0 2752 .0 Y 10

L4

L5 N

L6 20 .0 4 000 1863 .0 1874 .0 1868 .5 Y 27

L7

L8 23 .2 750 2209 .0 2330 .0 2269 .5 N 36

L9 20 .0 3535.0 3535.0 3535.0 Y 40

L11 25.0 1688 .0 2152 .0 1920 .0 Y 38

L12

L13

L14

L15

L16

L17 100 .0 2500 2994 .0 2840 .0 2917.0 N 35

L18

L19 20 .0 2 000 652 .0 655.0 653 .5 Y 47

L20

L21

L22

L23 25.0 3991.0 3641.0 3816 .0 Y 50

L24 2 .0 3376 .0 3417.0 3396 .5 N 25

L25

L26

L27 N

L28 20 .0 3200 .0 3100 .0 3150 .0 Y 32

L29

L30 25.0 2500 3000 .0 4400 .0 3700 .0 y 15

L32 20 .0 2900 .0 2400 .0 2650 .0 Y 44

N 13

Mean 2701.5

STDEV 885.0

Med ian 2752 .0

Med ian Ref

σ (hat)r ob


V a s s


FB

3

-4

-3

-2

-1

0

1

2

3

4

Sco

re

Lab number

z-scor e

zeta-s core

0

1000

2000

3000

4000

5000

6000

7000

µg k

g-1

Lab number

0

0 .2

0 .4

0 .6

0 .8

1

1 .2

0 0 .2 0 .4 0 .6 0 .8 1 1 .2

Kernel Density Plot


Table 14: ZEN


L1 35.0 1590 .0 1599 .4 1594 .7 Y 12

L2 1.0 2500 1830 .0 1918 .0 1874 .0 Y 12

L3 2 .4 2344 .0 2344 .0 2344 .0 Y 35

L4 1500 .0 1600 .0 1550 .0 Y 51

L5 9 .7 2346 .0 2382 .0 2364 .0 N

L6 20 .0 4 000 713 .0 769 .0 741.0 Y 27

L7 5.0 2502 .3 2215.1 2358 .7 Y 48

L8 17.9 6 00 1913 .0 2105.0 2009 .0 N 29

L9 10 .0 2200 .0 2200 .0 2200 .0 Y 40

L11 10 .0 2089 .0 2176 .0 2132 .5 Y 25

L12 10 .0 1806 .0 1845.0 1825.5 Y 25

L13 15.4 1582 .0 1716 .0 1649 .0 N 6

L14 40 .0 2500 .0 2500 .0 2500 .0 Y 42

L15 10 .0 4 00 1166 .1 1187.2 1176 .7 Y 46

L16 10 .0 1850 .0 2010 .0 1930 .0 N

L17 140 .0 3500 2455.0 2408 .0 2431.5 N 35

L18 10 .0 1884 .3 2046 .4 1965.4 Y 31

L19

L20 1.0 910 .1 830 .4 870 .3 N 13

L21 16 .0 2272 .0 2105.0 2188 .5 N 5

L22 50 .0 2741.6 2489 .6 2615.6 Y 50

L23 25.0 2354 .0 2310 .0 2332 .0 Y 13

L24 0 .2 2516 .0 2776 .0 2646 .0 N 25

L25 10 .0 10000 2111.0 2008 .0 2059 .5 N

L26 10 .0 2651.0 2200 .0 2425.5 Y 12

L27 20 .0 2380 .0 2300 .0 2340 .0 N

L28 50 .0 2200 .0 2100 .0 2150 .0 Y 28

L29 20 .0 2 000 1979 .0 1995.0 1987.0 Y 30

L30 5.0 2 000 1593 .7 1576 .4 1585.1 y 33

L32 10 .0 1910 .0 1630 .0 1770 .0 Y 19

N 29

Mean 1986 .7

STDEV 479 .6

Med ian 2059 .5

Med ian Ref

σ (hat)r ob


V a s s


ZE

N

-4

-3

-2

-1

0

1

2

3

4

Sco

re

Lab number

z-scor e

zeta-s core

0

500

1000

1500

2000

2500

3000

3500

4000

4500

µg k

g-1

Lab number

0

0 .00 02

0 .00 04

0 .00 06

0 .00 08

0 .00 1

0 1 00 0 2 00 0 3 00 0 4 00 0

Kernel Density Plot


Table 15: T2


L1 25.0 554 .4 547.7 551.1 Y 9 0 .4 1.4

L2 20 .0 500 427.7 416 .3 422 .0 Y 10 -1.0 - 3 .3

L3 1.0 595.2 595.2 595.2 Y 10 0 .9 2 .5

L4 460 .0 490 .0 475.0 Y 50 -0 .4 -0 .3

L5 12 .7 693 .9 547.0 620 .5 N 1.2

L6 20 .0 4 000 490 .0 488 .0 489 .0 Y 19 -0 .2 -0 .5

L7 10 .0 541.7 453 .9 497.8 Y 45 -0 .2 -0 .1

L8 9 .4 3 00 310 .0 325.0 317.5 N 38 - 2 .1 - 3 .1

L9 10 .0 615.0 615.0 615.0 Y 40 1.1 0 .8

L11 50 .0 691.0 627.0 659 .0 Y 24 1.6 1.8

L12 4 .0 538 .0 512 .0 525.0 Y 50 0 .2 0 .1

L13 6 .2 594 .8 586 .0 590 .4 N 3 0 .9 4 .4

L14 10 .0 400 .0 370 .0 385.0 Y 23 -1.4 - 2 .7

L15 5.0 2 00 585.2 611.2 598 .2 Y 37 1.0 0 .8

L16 10 .0 402 .0 455.0 428 .5 N -0 .9

L17 42 .0 1050 257.0 167.0 212 .0 N 30 - 3 .3 - 8 .4

L18 20 .0 663 .5 556 .3 609 .9 Y 39 1.1 0 .8

L19 10 .0 1000 476 .0 480 .0 478 .0 Y 46 -0 .4 -0 .3

L20 0 .5 199 .6 148 .4 174 .0 N 30 - 3 .7 - 11.1

L21 9 .6 573 .0 547.6 560 .3 N 3 0 .5 2 .7

L22 13 .0 655.7 518 .7 587.2 Y 50 0 .8 0 .5

L23 5.0 623 .0 569 .1 596 .1 Y 13 0 .9 2 .0

L24 0 .5 397.4 396 .0 396 .7 N 25 -1.3 - 2 .2

L25 20 .0 1000 735.0 646 .0 690 .5 N 2 .0

L26 50 .0 320 .9 295.0 308 .0 Y 50 - 2 .2 - 2 .6

L27 30 .0 579 .0 612 .0 595.5 N 0 .9

L28 20 .0 160 .0 200 .0 180 .0 Y 27 - 3 .7 - 11.4

L29 80 .0 4 800 549 .3 578 .3 563 .8 Y 30 0 .6 0 .6

L30 5.0 2 000 613 .4 514 .9 564 .2 y 12 0 .6 1.4

L32 5.0 520 .0 680 .0 600 .0 Y 22 1.0 1.3

N 30

Mean 496 .2

STDEV 141.1

Med ian 555.7

Med ian Ref 511.4

σ (hat)r ob 92 .0


V a s s 511.4

u s t a n d a r d ( u( x a ) ) 15 .8

T2

-13-12-11-10-9-8-7-6-5-4-3-2-10123456

Sco

re

Lab number

z-scor e

zeta-s core

0

100

200

300

400

500

600

700

800

900

1000

µg k

g-1

Lab number

0

0 .00 1

0 .00 2

0 .00 3

0 .00 4

0 .00 5

0 2 00 4 00 6 00 8 00 1 00 0

Kernel Density Plot


Table 16: HT2


L1 25.0 128 .6 129 .8 129 .2 Y 12

L2 20 .0 500 147.9 174 .8 161.4 Y 16

L3 1.0 117.9 117.9 117.9 Y 10

L4 200 .0 200 .0 200 .0 200 .0 N 73

L5 22 .3 97.2 94 .2 95.7 N

L6 20 .0 8 000 133 .0 92 .0 112 .5 Y 25

L7 10 .0 155.2 133 .8 144 .5 Y 34

L8 9 .2 2 00 96 .0 112 .0 104 .0 N 38

L9 10 .0 112 .0 112 .0 112 .0 Y 40

L11 50 .0 164 .0 169 .0 166 .5 Y 15

L12 4 .0 144 .0 184 .0 164 .0 Y 45

L13 12 .3 123 .0 119 .9 121.5 N 1

L14 10 .0 79 .0 72 .0 75.5 Y 16

L15 5.0 2 00 145.8 147.2 146 .5 Y 37

L16 10 .0 87.2 95.8 91.5 N

L17 40 .0 1000 192 .0 161.0 176 .5 N 25

L18 50 .0 124 .3 125.2 124 .8 Y 27

L19 10 .0 1000 96 .0 104 .0 100 .0 Y 48

L20 0 .5 21.9 18 .1 20 .0 N 30

L21 9 .6 137.7 134 .1 135.9 N 2

L22 17.0 117.3 128 .7 123 .0 Y 50

L23 5.0 138 .8 139 .8 139 .3 Y 16

L24 2 .0 102 .0 106 .3 104 .2 N 25

L25 20 .0 1000 181.0 157.0 169 .0 N

L26 50 .0 105.0 85.0 95.0 Y 65

L27 60 .0 119 .0 127.0 123 .0 N

L28 50 .0 330 .0 350 .0 340 .0 Y 35 Y

L29 160 .0 9 600 143 .0 145.5 144 .3 Y 30

L30 5.0 2 000 118 .7 153 .5 136 .1 y 19

L32 5.0 180 .0 180 .0 180 .0 Y 37

N 30

Mean 135.1

STDEV 52 .8

Med ian 127.0

Med ian Ref

σ (hat)r ob


V a s s


HT

2

-4

-3

-2

-1

0

1

2

3

4

Sco

re

Lab number

z-scor e

zeta-s core

0

50

100

150

200

250

300

350

400

µg k

g-1

Lab number

0

0 .00 2

0 .00 4

0 .00 6

0 .00 8

0 .01

0 .01 2

-10 0 0 1 00 2 00 3 00

Kernel Density Plot


Table 17: Sum of T2 and HT2


L1 50 .0 683 .0 677.4 680 .2 y 15 -0 .1 -0 .2

L2 40 .0 1000

L3 2 .0 713 .2 713 .2 713 .2 Y 15 0 .2 0 .4

L4

L5 N

L6 20 .0 4 000 623 .0 580 .0 601.5 Y 22 -0 .8 -1.3

L7 20 .0 696 .9 587.7 642 .3 Y 40 -0 .4 -0 .4

L8 405.0 437.0 421.0 N 51 - 2 .3 - 2 .5

L9 727.0 727.0 727.0 Y 40 0 .3 0 .3

L11 100 .0 855.0 796 .0 825.5 Y 24 1.2 1.4

L12 4 .0 682 .0 696 .0 689 .0 Y 50 0 .0 0 .0

L13 18 .5 717.7 706 .0 711.8 N 0 .2

L14 20 .0 479 .0 442 .0 460 .5 Y 28 -2 .0 - 3 .5

L15 10 .0 4 00 731.0 758 .4 744 .7 Y 37 0 .5 0 .4

L16 20 .0 489 .0 551.0 520 .0 N -1.4

L17

L18 50 .0 787.8 681.5 734 .7 Y 39 0 .4 0 .3

L19

L20 221.5 166 .5 194 .0 N - 4 .2 Y

L21 710 .7 681.7 696 .2 N 3 0 .1 0 .5

L22 30 .0 773 .0 647.4 710 .2 Y 50 0 .2 0 .1

L23 5.0 761.8 708 .9 735.4 Y 14 0 .4 0 .9

L24 499 .4 502 .3 500 .9 N 25 -1.6 - 2 .9

L25 916 .0 803 .0 859 .5 N 1.5

L26 50 .0 425.9 380 .0 403 .0 Y 55 - 2 .5 - 2 .6

L27 N

L28 70 .0 490 .0 550 .0 520 .0 Y 44 -1.4 -1.5

L29 80 .0 14400 692 .3 723 .8 708 .1 Y 30 0 .2 0 .2

L30 732 .1 668 .4 700 .3 n 0 .1

L32 10 .0 700 .0 870 .0 785.0 Y 37 0 .8 0 .7

N 24

Mean 636 .8

STDEV 155.4

Med ian 698 .2

Med ian Ref 689 .0

σ (hat)r ob 68 .9


V a s s 6 8 9 .0

u s t a n d a r d ( u( x a ) ) 13 .3

SU

M H

T2 T

2

-4

-3

-2

-1

0

1

2

3

4

Sco

re

Lab number

z-scor e

zeta-s core

0

200

400

600

800

1000

1200

µg k

g-1

Lab number

0

0 .00 05

0 .00 1

0 .00 15

0 .00 2

0 .00 25

0 .00 3

0 .00 35

0 2 00 4 00 6 00 8 00 1 00 0 1 20 0

Kernel Density Plot


Table 18: OTA


L1 1.0 52 .0 24 .4 38 .2 Y 24

L2 5.0 500 23 .2 26 .6 24 .9 Y 13

L3 0 .5 16 .3 16 .3 16 .3 Y 20

L4 10 .0 7.9 9 .0 Y 48

L5 21.0 N

L6 2 .0 4 000 8 .1 11.4 9 .8 Y 26

L7 1.0 15.2 26 .3 20 .7 Y 34

L8 3 .4 150 10 .7 10 .9 10 .8 N 12

L9 0 .2 17.1 17.1 17.1 Y 40

L11 0 .1 10 .0 9 .6 9 .8 Y 24

L12 1.0 16 .2 19 .8 18 .0 Y 41

L13 2 .5 22 .1 15.3 18 .7 N 7

L14 5.0 25.0 26 .0 25.5 Y 18

L15 1.0 30 20 .3 20 .9 20 .6 Y 44

L16 2 .0 12 .9 13 .0 13 .0 N

L17 2 .0 50 14 .7 13 .9 14 .3 N 40

L18 0 .5 16 .5 22 .5 19 .5 Y 22

L19

L20 0 .2 8 .9 3 .8 6 .3 N 30

L21 1.6 17.1 15.6 16 .3 N 6

L22 48 .0 15.9 25.2 20 .6 Y 50

L23 0 .5 16 .3 17.7 17.0 Y 12

L24 0 .2 12 .5 15.4 14 .0 N 25

L25 1.0 1000 17.6 31.7 24 .7 N

L26 1.0 25.3 24 .8 25.1 Y 24

L27 0 .6 15.6 19 .0 17.3 N

L28 2 .0 33 .0 33 .0 33 .0 Y 34

L29 20 .0 1200 17.3 15.5 16 .4 Y 30

L30 0 .5 50 3 .6 3 .8 3 .7 y 34

L32 1.0 18 .0 41.0 29 .5 Y 30

N 28

Mean 18 .2

STDEV 7.8

Med ian 17.2

Med ian Ref

σ (hat)r ob


V a s s


OT

A

-4

-3

-2

-1

0

1

2

3

4

Sco

re

Lab number

z-scor e

zeta-s core

0

5

10

15

20

25

30

35

40

45

50

µg k

g-1

Lab number

0

0 .01

0 .02

0 .03

0 .04

0 .05

0 .06

0 .07

-10 0 1 0 2 0 3 0 4 0 5 0

Kernel Density Plot


Table 19: NIV


L1

L2 10 .0 2 000 205.5 202 .9 204 .2 Y 29

L3 10 .0 295.0 295.0 295.0 Y 25

L4 150 .0 150 .0 150 .0 150 .0 N 50

L5 29 .5 75.6 84 .7 80 .2 N

L6

L7 50 .0 140 .9 188 .0 164 .5 Y 44

L8 36 .2 6 00 107.0 125.0 116 .0 N 31

L9 20 .0 125.0 125.0 125.0 Y 40

L11 50 .0 150 .0 116 .0 133 .0 N

L12

L13

L14

L15

L16

L17

L18 100 .0 105.6 115.7 110 .7 Y 32

L19

L20

L21

L22

L23 N

L24 1.0 158 .4 162 .6 160 .5 N 25

L25

L26

L27 60 .0 178 .0 186 .0 182 .0 N

L28 100 .0 230 .0 230 .0 230 .0 Y 26

L29 80 .0 4 800 101.0 107.0 104 .0 Y 30

L30 100 .0 4 000 n

L32

N 13

Mean 158 .1

STDEV 58 .8

Med ian 150 .0

Med ian Ref

σ (hat)r ob


V a s s


NIV

-4

-3

-2

-1

0

1

2

3

4

Sco

re

Lab number

z-scor e

zeta-s core

0

50

100

150

200

250

300

350

400

µg k

g-1

Lab number

0

0 .2

0 .4

0 .6

0 .8

1

1 .2

0 0 .2 0 .4 0 .6 0 .8 1 1 .2

Kernel Density Plot


Table 20: BEA


L1

L2 0 .5 1000 344 .0 316 .0 330 .0 Y 27

L3

L4

L5 69 .2 258 .7 263 .8 261.3 N

L6

L7

L8

L9 10 .0 402 .0 402 .0 402 .0 Y 40

L11

L12

L13

L14

L15

L16

L17

L18

L19 10 .0 1000 304 .0 289 .0 296 .5 Y 44

L20

L21

L22

L23 25.0 334 .8 323 .6 329 .2 Y 50

L24 0 .0 235.4 230 .0 232 .7 N 25

L25

L26

L27 2 .0 256 .0 239 .0 247.5 N

L28 25.0 390 .0 410 .0 400 .0 Y 45

L29

L30

L32

N 8

Mean 312 .4

STDEV 65.2

Med ian 312 .9

Med ian Ref

σ (hat)r ob


V a s s


BE

A

-4

-3

-2

-1

0

1

2

3

4

Sco

re

Lab number

z-scor e

zeta-s core

0

100

200

300

400

500

600

700

µg k

g-1

Lab number

0

0 .2

0 .4

0 .6

0 .8

1

1 .2

0 0 .2 0 .4 0 .6 0 .8 1 1 .2

Kernel Density Plot


Table 21: EnnA


L1

L2

L3

L4

L5 45.1 N

L6

L7

L8

L9 10 .0 7.0 7.0 7.0 Y 40

L11

L12

L13

L14

L15

L16

L17

L18

L19

L20

L21

L22

L23 25.0 0 .1 0 .1 0 .1 Y 50

L24 0 .0 0 .7 0 .6 0 .6 N 25

L25

L26

L27 2 .0 N

L28 50 .0 Y 33

L29

L30

L32

N 3

Mean 2 .6

STDEV 3.8

Med ian 0 .6

Med ian Ref

σ (hat)r ob


V a s s


En

nA

-4

-3

-2

-1

0

1

2

3

4

Sco

re

Lab number

z-scor e

zeta-s core

0

2

4

6

8

10

12

µg k

g-1

Lab number

0

0 .2

0 .4

0 .6

0 .8

1

1 .2

0 0 .2 0 .4 0 .6 0 .8 1 1 .2

Kernel Density Plot


Table 22: EnnA1


L1

L2

L3

L4

L5 67.2 15.5 16 .1 15.8 N

L6

L7

L8

L9 10 .0 51.0 51.0 51.0 Y 40 Y

L11

L12

L13

L14

L15

L16

L17

L18

L19

L20

L21

L22

L23 25.0 23 .2 25.0 24 .1 Y 50

L24 0 .0 16 .8 15.1 16 .0 N 25

L25

L26

L27 5.0 20 .0 17.4 18 .7 N

L28 50 .0 Y 26

L29

L30

L32

N 5

Mean 25.1

STDEV 14 .9

Med ian 18 .7

Med ian Ref

σ (hat)r ob


V a s s


En

nA

1

-4

-3

-2

-1

0

1

2

3

4

Sco

re

Lab number

z-scor e

zeta-s core

0

5

10

15

20

25

30

35

40

µg k

g-1

Lab number

0

0 .2

0 .4

0 .6

0 .8

1

1 .2

0 0 .2 0 .4 0 .6 0 .8 1 1 .2

Kernel Density Plot


Table 23: EnnB


L1

L2 0 .5 2500 1116 .0 904 .0 1010 .0 Y 15

L3

L4

L5 94 .5 589 .9 619 .6 604 .8 N

L6

L7

L8 512 .0 510 .0 511.0 N

L9 10 .0 764 .0 764 .0 764 .0 Y 40

L11

L12

L13

L14

L15

L16

L17

L18

L19

L20

L21

L22

L23 25.0 592 .1 635.0 613 .6 Y 50

L24 0 .0 475.2 448 .6 461.9 N 25

L25

L26

L27 16 .0 271.0 257.0 264 .0 N

L28 50 .0 570 .0 540 .0 555.0 Y 27

L29

L30

L32

N 8

Mean 598 .0

STDEV 219 .4

Med ian 579 .9

Med ian Ref

σ (hat)r ob


V a s s


En

nB

-4

-3

-2

-1

0

1

2

3

4

Sco

re

Lab number

z-scor e

zeta-s core

0

200

400

600

800

1000

1200

1400

µg k

g-1

Lab number

0

0 .2

0 .4

0 .6

0 .8

1

1 .2

0 0 .2 0 .4 0 .6 0 .8 1 1 .2

Kernel Density Plot


Table 24: EnnB1


L1

L2

L3

L4

L5 64 .9 101.1 111.8 106 .5 N

L6

L7

L8

L9 10 .0 197.0 197.0 197.0 Y 40 Y

L11

L12

L13

L14

L15

L16

L17

L18

L19

L20

L21

L22

L23 25.0 102 .0 114 .2 108 .1 Y 50

L24 0 .0 146 .0 134 .9 140 .5 N 25

L25

L26

L27 16 .0 132 .0 121.0 126 .5 N

L28 50 .0 97.0 140 .0 118 .5 Y 29

L29

L30

L32

N 6

Mean 132 .8

STDEV 33 .8

Med ian 122 .5

Med ian Ref

σ (hat)r ob


V a s s


En

nB

1

-4

-3

-2

-1

0

1

2

3

4

Sco

re

Lab number

z-scor e

zeta-s core

0

20

40

60

80

100

120

140

160

180

200

µg k

g-1

Lab number

0

0 .2

0 .4

0 .6

0 .8

1

1 .2

0 0 .2 0 .4 0 .6 0 .8 1 1 .2

Kernel Density Plot


Table 25: FusX


L1

L2

L3

L4

L5 23 .7 350 .0 366 .6 358 .3 N

L6

L7

L8 16 .6 6 00 237.0 272 .0 254 .5 N 14

L9 10 .0 218 .0 218 .0 218 .0 Y 40

L11 50 .0 350 .0 356 .0 353 .0 N

L12

L13

L14

L15

L16 10 .0 281.0 259 .0 270 .0 N

L17

L18

L19 20 .0 500 182 .0 175.0 178 .5 Y 51

L20

L21

L22

L23 100 .0 282 .5 281.9 282 .2 Y 50

L24 2 .0 315.8 319 .5 317.7 N 25

L25

L26

L27 N

L28

L29 400 .0 2 40 00 310 .5 281.0 295.8 Y 50

L30 100 .0 4 000 210 .0 250 .0 230 .0 n

L32

N 10

Mean 275.8

STDEV 58 .1

Med ian 276 .1

Med ian Ref

σ (hat)r ob


V a s s


Fu

sX

-4

-3

-2

-1

0

1

2

3

4

Sco

re

Lab number

z-scor e

zeta-s core

0

50

100

150

200

250

300

350

400

450

500

µg k

g-1

Lab number

0

0 .2

0 .4

0 .6

0 .8

1

1 .2

0 0 .2 0 .4 0 .6 0 .8 1 1 .2

Kernel Density Plot


Table 26: CIT


L1

L2

L3

L4

L5 N

L6

L7

L8

L9 30 .0 6 .0 6 .0 6 .0 Y 40

L11

L12

L13

L14

L15 50 .0 4 000 39 .0 30 .0 34 .5 Y 42

L16

L17 10 .0 3 000 11.1 8 .9 10 .0 N 40

L18

L19

L20

L21

L22

L23 25.0 1.1 1.3 1.2 Y 50

L24 0 .1 5.6 5.2 5.4 N 25

L25

L26

L27 2 .0 31.8 29 .9 30 .9 N

L28 50 .0 Y 60

L29 3 .0 2 .0 2 .1 2 .0 Y 40

L30 25.0 1000 n

L32

N 7

Mean 12 .8

STDEV 13 .9

Med ian 6 .0

Med ian Ref

σ (hat)r ob


V a s s


CIT

-4

-3

-2

-1

0

1

2

3

4

Sco

re

Lab number

z-scor e

zeta-s core

0

10

20

30

40

50

60

µg k

g-1

Lab number

0

0 .2

0 .4

0 .6

0 .8

1

1 .2

0 0 .2 0 .4 0 .6 0 .8 1 1 .2

Kernel Density Plot


Table 27: 3-acetyl-deoxynivalenol (3AcDON)


L1

L2 10 .0 2 000 38 .7 34 .5 36 .6 Y 21

L3

L4

L5 14 .7 66 .9 41.4 54 .1 N

L6

L7

L8 4 .9 500 23 .0 24 .0 23 .5 N 38

L9 10 .0 19 .0 19 .0 19 .0 Y 40

L11

L12

L13

L14

L15

L16

L17

L18 50 .0 Y 27

L19

L20

L21

L22

L23 25.0 20 .4 19 .5 20 .0 Y 50

L24 4 .0 40 .8 36 .3 38 .6 N 25

L25

L26

L27 50 .0 N

L28 80 .0 Y 34

L29 400 .0 2 40 00 Y 30

L30 10 .0 4 000 n

L32

N 6

Mean 32 .0

STDEV 13 .7

Med ian 30 .1

Med ian Ref

σ (hat)r ob


V a s s


3-A

cD

ON

-4

-3

-2

-1

0

1

2

3

4

Sco

re

Lab number

z-scor e

zeta-s core

0

10

20

30

40

50

60

µg k

g-1

Lab number

0

0 .2

0 .4

0 .6

0 .8

1

1 .2

0 0 .2 0 .4 0 .6 0 .8 1 1 .2

Kernel Density Plot


Table 28: 15-acetyl-deoxynivalenol (15AcDON)


L1

L2 10 .0 2 000 75.6 64 .4 70 .0 Y 16

L3

L4

L5 54 .2 150 .1 76 .1 113 .1 N

L6 100 .0 4 000 Y 35

L7

L8 3 .1 250 62 .0 57.0 59 .5 N 38

L9 10 .0 37.0 37.0 37.0 Y 40

L11

L12

L13

L14

L15

L16

L17

L18 50 .0 Y 27

L19

L20

L21

L22

L23 100 .0 49 .1 52 .0 50 .5 Y 50

L24 4 .0 40 .8 49 .8 45.3 N 25

L25

L26

L27 50 .0 132 .0 135.0 133 .5 N

L28 200 .0 Y 17

L29 400 .0 2 40 00 61.9 49 .3 55.6 Y 50

L30 10 .0 4 000 n

L32

N 8

Mean 70 .6

STDEV 34 .4

Med ian 57.6

Med ian Ref

σ (hat)r ob


V a s s


15-A

cD

ON

-4

-3

-2

-1

0

1

2

3

4

Sco

re

Lab number

z-scor e

zeta-s core

0

20

40

60

80

100

120

140

160

µg k

g-1

Lab number

0

0 .2

0 .4

0 .6

0 .8

1

1 .2

0 0 .2 0 .4 0 .6 0 .8 1 1 .2

Kernel Density Plot


6 Discussion and Conclusion

An assigned value could be attributed for the following molecules: AfB1, AfG1, DON, T2 and the sum T2/HT2.

For some compounds under regulation no assigned value could be attributed because the HorRat values exceeded the

accepted limit and the distribution was not clearly unimodal and symmetric. This was the case for HT2, FB1, FB2, ZEN,

OTA and the sums of aflatoxins, and the sum of FB1 and FB2.

Although no assigned value could be established for HT2, an assigned value could however be assigned to the sum, this

can probably be explained by the fact that concentration of T2 is much higher and this dictates the assigned value. The

concentrations of AfB2 and AfG2 were at or below the reported LOQs of most participants; this probably explains the

large variation in results. A similar trend was observed with the PT for mycotoxins in wheat flour organized by CODA-

CERVA in 2016.

For the compounds that are not under regulation, 3AcDON, 15AcDON, FusX, NIV, Enns, BEA and CIT no assigned

value could be established. For these analytes no certified reference standards and/or isotopically labelled internal

standards are readily available. A similar observation was made in the PT of 2016.

The ζ-scores are on the whole not as good as the z-scores as observed in the PT of 2014, 2015 and 2016. This might be

due to participants underestimating their measurement uncertainty.


7 Bibliography

· M. Thompson, S. L. R. Ellison, and R. Wood, “The International Harmonized Protocol for the proficiency testing

of analytical chemistry laboratories (IUPAC Technical Report),” Pure Appl. Chem., vol. 78, no. 1, pp. 145–196, 2006.

· I. Kuselman and A. Fajgelj, “IUPAC/CITAC Guide: Selection and use of proficiency testing schemes for a limited

number of participants—chemical analytical laboratories (IUPAC Technical Report),” Pure Appl. Chem., vol. 82, no.

5, pp. 1099–1135, 2010.

· AMC, “Robust statistics: a method of coping with outliers,” AMC Tech. Br., no. 6, 2001.

· M. Thompson, “The amazing Horwitz function,” AMC Tech. Br., no. 17, 2004.

· ISO 13528, Statistical methods for use in proficiency testing by interlaboratory comparison, vol. 2015. 2015.

· The international harmonized protocol for the proficiency testing of analytical chemistry laboratories (iupac

technical report), pure appl. chem., 78 (1), pp. 145–196, 2006.

· Manfred Metzler, “Proposal for a uniform designation of zearalenone and its metabolites”, Mycotox Res, 27 (1), pp.

1-3, 2011

· Solfrizzo M, ., De Girolamo A., M T Lattanzio V. M.T., van Egmond H., Results of a proficiency test for multi-

mycotoxin determination in maize by using methods based on LC-MS/(MS)”, Quality Assurance and Safety of

crops & foods, March 2013, 5 (1), pp. 15-48, 2013.

· CODA-CERVA, Report on the 2011 Proficiency Test for the determination of deoxynivalenol, HT-2 and T-2

toxins, zearalenone, beauvericin and enniatins A, A1 B and B1 in cereal flour

· CODA-CERVA, Report on the 2012 Proficiency Test for the determination of 17 mycotoxins in cereal flour

· CODA-CERVA, Report on the 2013 Proficiency Test for the determination of 17 mycotoxins in oats flour

· CODA-CERVA, Report on the 2014 Proficiency Test for the determination of 19 mycotoxins and 4 sums of

mycotoxins in rye flour

· CODA-CERVA, Report on the 2015 Proficiency Test for the determination of 19 mycotoxins and 4 sums of

mycotoxins in barley malt

· CODA-CERVA, Report on the 2016 Multimycotoxin Proficiency Test: Determining 23 mycotoxins in wheat flour


8 Annexes

8.1 Annex 1: Invitation letter to the laboratories


8.2 Annex 2: PT registration form

8.3 Annex 3: Instructions to the participants


8.4 Annex 4: Receipt form

8.5 Annex 5: Report form


8.6 Annex 6: List of the participating laboratories

Glasgow Scientific Services

Lab of physicochemical Research, Zhejiang Provincal center for Disease control and Prevention

Australian Superintendence Company

NutriControl BV

Norwegian veterinary Institute

The Southern African Grain Laboratory NPC

Dr A. VERWRY BV, Member of the Agrolab group

Ghent University - Laboratory of Food Analysis

Eurofins Wej Contaminants GmbH

Phytocontrol

Laboratorium ECCA NV

R-Biopharm Rhone

SGS Belgium nv

IZSLER Chemical Department - Bologna

LOVAP

FLVVT

Primoris Belgium

Chinese Academy of Agriculture Sciences, Oil Crops Research Institute

Food Research Division, Bureau of Chemical Safety, Health Canada

Patent Co

LAVES Futtermittelinstitut Stade

CER Groupe

Center for Analytical Chemistry, Department IFA-Tulln, BOKU Vienna

Nutreco Nederland BV - MasterLab

NOFALAB B.V.

Canadian Grain Commission; TOTE

RIKILT Wageningen University & Research

AGES GmbH

Trilogy Analytical Laboratory

OLEOTEST N.V.


8.7 Annex 7: Stability

“The short-term stability study was conducted following an isochronous experimental design. Storage at -20°C was

chosen as reference temperature for sample storage. Stability was evaluated according to the International Harmonized

Protocol for the Proficiency Testing of Analytical Chemistry Laboratories. The material proved to be adequately stable at

-20°C and +4 °C for the period between dispatch and the deadline for submission of results”

8.8 Annex 7: Homogeneity

The materials were tested for homogeneity according to the IUPAC International Harmonized Protocol. Briefly, 12

samples were selected at random, and from each sample two 5 g subsamples were extracted and analysed with a “dilute-

and-shoot” LC-MS/MS method.

The target standard deviations (σp) used were calculated by applying the Horwitz-Thompson function to the MedianRef.

The calculations performed and the acceptance criteria are based on the IUPAC 2006 protocol:

· The condition for “sufficient homogeneity” is that the true between-samples variability (σsampl.) does not exceed

σsampl.allow. = 0.3 σp

· The SD of the 12 average results includes a contribution from the between-samples variability and a contribution

from the analytical variability sanal ; therefore, if this SD is:

o < 0.3 σp : then the material is certainly sufficiently homogenous

o > 0.3 σp : then the critical value test described below should be applied

· The observed between-samples variability ssampl. is calculated by ANOVA substraction of the observed analytical

variability sanal. from the variability of the 12 averages :

(ssampl.)2 = (s(12 averages))2 – (sanal.)2 / 2

· For this calculation, the analytical variability is assimilated to the between-subsamples variability (which implies that

each sample has been perfectly homogenized before sub-sampling) :

(sanal.)2 = average of the 12 (s(2 subsamples))2

· It is not uncommon in actual practice that (sanal.2) / 2 > (s(12 averages))2, so that the result of the ANOVA subtraction is

negative. In this case ssampl. is set to 0. This can happen when the real between-samples variability σsampl. is indeed

small, but also when σsampl. is relatively large but sanal. /!2 is even larger (see next point)


· Because of the ANOVA subtraction, if sanal. is not small enough, important sampling variation may be obscured by

analytical variation. We may get a non-significant result when testing for heterogeneity, not because it is not present,

but because the test has no power to detect it. Therefore it is recommended that σanal. < 0.5 σp.

· Finally the hypothesis of sufficient homogeneity

H:(σsampl.)2≤(σsampl.allow).2

is tested, and rejected if the 95% confidence interval around σsampl. does not include σsampl.allow., i.e. when the

observed sampling variability exceeds a certain critical value :

(ssampl.)2 > c = F1 (σsampl.allow.)2 + F2 (sanal.)2

where F1 and F2 are constants that may be derived from standard statistical tables. For 12 samples, F1 = 1.79 and

F2 = 0.86, so that !" ≥ 1.34 σsampl.allow.. In other words this test, being based on a 95% confidence interval, is less

stringent than direct comparison between ssampl. and σsampl.allow. (a test which, in case a material had ssampl. = σsampl.allow.,

would actually give 50% probability of wrongly rejecting it)

Table 29 gives, for each toxin:

· The results for each subsample and sample

· The between-samples RSD

· The ANOVA calculations

· The details of the critical value test

· σsampl.allow., sanal. and ssampl., in µg/kg

· The critical value c

· The square root of this critical value

· The ratio of this square root to σsampl.allow.

· The ratio of ssampl. to the square root of c

· ssampl.2 and the result of the test :

§ “PASS” if (ssampl.2 < c) and (sanal. < 0.5 σp)

§ “(PASS)” if (ssampl.2 < c) but (sanal. > 0.5 σp)

§ “FAIL” if (ssampl.2 > c)


Table 29: Homogeneity

Inj 1 Inj 2 Inj 1 Inj 2 Inj 1 Inj 2 Inj 1 Inj 2 Inj 1 Inj 2 Inj 1 Inj 2 Inj 1 Inj 2 Inj 1 Inj 2

Analysis 1 7220.4 8381.1 1431.9 1643.7 2601.1 2926.4 794.2 930.0 2400.9 2373.1 521.2 533.2 102.1 103.9 4.6 5.5

Analysis 2 7853.1 7853.1 1557.4 1547.8 2723.2 2727.5 1020.9 882.7 2329.2 2381.8 543.9 570.9 109.3 115.2 7.0 7.0

Analysis 3 7800.1 7713.9 1515.0 1559.4 2812.0 2863.2 778.2 850.2 2234.9 2219.0 546.8 582.4 108.7 111.8 6.2 4.8

Analysis 4 8033.4 8003.4 1617.6 1606.3 2903.4 2824.0 935.0 955.0 2356.2 2165.1 590.8 564.4 112.3 106.0 5.0 6.5

Analysis 5 7784.2 7392.1 1533.5 1453.2 2840.1 2669.9 834.3 736.2 2388.5 2453.8 573.5 508.2 109.2 102.1 5.5 5.5

Analysis 6 7568.0 8062.1 1529.4 1639.7 2692.1 2974.9 808.6 894.3 2291.2 2503.9 618.8 664.9 125.7 125.4 5.4 5.1

Analysis 7 8668.0 10070.3 1724.8 2048.7 3131.7 3529.5 896.2 1058.6 2420.1 2707.1 646.9 681.0 122.7 130.1 7.4 7.2

Analysis 8 7668.8 8204.0 1460.4 1680.1 2631.9 2939.2 796.5 899.8 2416.9 2585.9 611.6 596.0 116.2 115.3 6.9 5.1

Analysis 9 7873.7 8327.3 1519.1 1651.4 2659.9 3005.1 805.1 895.8 2023.3 2352.4 600.9 543.5 112.7 105.4 6.6 5.7

Analysis 10 9390.1 12643.7 1872.6 2597.7 3420.2 4582.9 1127.3 2796.7 4030.4 711.3 1047.2 134.2 190.5 6.0 7.6

Analysis 11 7897.1 7929.4 1591.4 1594.2 2809.1 2869.5 859.5 972.3 2341.7 2373.0 542.6 590.3 105.7 113.6 5.7 5.8

Analysis 12 9131.7 7796.3 1796.6 1555.6 3245.2 2701.5 1057.4 818.1 2365.1 2170.2 578.9 549.9 113.9 108.6 5.5 5.7

Median 7913.3 1592.8 2851.7 894.3 2373.1 580.7 112.5 5.7

σ(anal) 9.90% 11.26% 10.06% 8.51% 11.73% 12.58% 10.73% 12.18%

σ(an)/(σ(H-Th)/2) 2 2 1 1 2 1 1 1

=> expected RSD(averages(2subsamples)) 7.00% 7.96% 7.11% 6.02% 8.29% 8.90% 7.59% 8.61%

observed RSD (averages(2subsamples)) 12.31% 13.21% 12.90% 10.63% 13.61% 16.20% 14.26% 12.29%

RSD(av.2 subs. 5g) / (0.3 σ(H-Th)) 3.53 2.97 3.17 2.18 3.25 3.13 2.16 1.86

observed RSD (all subsamples) 13.59% 14.74% 14.16% 11.15% 15.27% 17.57% 15.31% 14.36%

RSD(50g, expected) 4.30% 4.66% 4.48% 3.52% 4.83% 5.56% 4.84% 4.54%

RSD(50g, expected) / (0.3 σ(H-Th)) 1.23 1.05 1.10 0.72 1.15 1.07 0.73 0.69

s(sampling, bag) (%) 10.13% 10.55% 10.76% 8.76% 10.79% 13.54% 12.07% 8.76%

F1 1.83 1.83 1.83 1.83 1.83 1.83 1.83 1.83

F2 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93

s(allowable) (µg/kg) 289.37 73.58 120.70 44.00 103.16 31.48 7.73 0.40

s(analyt) (µg/kg) 820.17 186.12 297.80 76.84 288.57 76.58 12.57 0.73

s(sam) (µg/kg) 839.42 174.36 318.72 79.05 265.64 82.43 14.14 0.53

c (= F1 σall 2 + F2 san 2) 778829.97 42124.54 109135.42 9033.93 96920.05 7268.28 256.53 0.78

(sqrt(c), as %) 10.65% 12.41% 11.16% 10.53% 12.65% 14.01% 13.67% 14.76%

s2sam 704624.94 30400.66 101585.45 6248.50 70562.93 6795.43 200.04 0.28

s(sam)/sqrt(c) 0.95 0.85 0.96 0.83 0.85 0.97 0.88 0.59

PASS ? (s2 sam < c ?) PASS PASS PASS PASS PASS PASS PASS PASS

FB2 FB3FB1 DON ZEN T2 HT2 AF B1

Inj 1 Inj 2 Inj 1 Inj 2 Inj 1 Inj 2 Inj 1 Inj 2 Inj 1 Inj 2 Inj 1 Inj 2 Inj 1 Inj 2 Inj 1 Inj 2

0.6 0.7 1.4 1.6 0.0 0.0 10.7 9.1 0.0 0.0 11.9 7.4 51.7 49.6 131.7 119.6

0.0 0.0 2.1 1.7 0.0 0.0 10.5 9.3 0.0 0.0 10.5 6.0 59.2 49.3 133.2 115.0

0.0 0.0 2.0 1.3 0.0 0.0 12.3 10.2 0.7 0.0 8.0 11.1 48.3 67.9 119.6 148.5

0.0 0.0 1.5 2.0 0.0 0.0 9.8 9.7 0.0 0.5 9.1 13.8 55.9 63.8 122.2 126.5

0.7 0.0 1.6 1.6 0.0 0.0 8.8 12.5 0.0 0.0 9.8 7.8 52.8 56.7 119.4 134.6

0.0 0.0 1.5 1.4 0.0 0.0 13.2 8.9 0.0 0.0 12.1 6.9 80.6 62.5 144.4 118.8

0.8 0.0 2.7 2.2 0.0 0.0 11.0 9.5 0.7 0.0 9.3 9.6 48.4 60.2 124.3 129.7

0.8 0.0 1.9 1.5 0.0 0.0 8.4 13.9 0.0 0.8 6.8 12.5 47.2 66.7 115.9 116.7

0.7 0.0 2.0 1.7 0.0 0.0 10.8 13.9 0.0 0.0 9.4 9.7 58.6 65.0 132.0 146.1

0.7 0.0 1.8 1.9 0.0 0.0 11.7 8.9 0.6 0.0 6.3 10.7 51.2 52.1 111.7 110.3

0.7 0.7 1.8 1.7 0.0 0.0 8.9 11.5 0.0 0.0 11.4 11.4 48.7 56.8 115.9

0.0 0.7 1.7 1.8 0.0 0.0 12.3 10.4 0.0 0.0 12.0 12.2 77.6 53.3 130.6 129.6

0.0 1.7 10.4 0.0 9.7 56.3 124.3

121.75% 14.62% 19.72% 211.79% 27.69% 14.58% 8.84%

11 1 2 19 3 1 1

86.09% 10.34% 13.94% 149.76% 19.58% 10.31% 6.25%

88.92% 15.14% 7.47% 116.92% 10.55% 10.40% 6.62%

13.47 2.29 1.13 17.71 1.60 1.58 1.01

123.52% 17.38% 15.68% 184.76% 22.76% 15.92% 8.60%

39.06% 5.50% 4.96% 58.43% 7.20% 5.03% 2.72%

5.92 0.83 0.75 8.85 1.09 0.76 0.41

22.23% 11.06% 0.00% 0.00% 0.00% 1.36% 2.19%

1.83 1.83 1.83 1.83 1.83 1.83 1.83

0.93 0.93 0.93 0.93 0.93 0.93 0.93

0.02 0.12 0.70 0.01 0.63 3.76 8.21

0.35 0.26 2.10 0.31 2.66 8.31 11.06

0.06 0.20 0.00 0.00 0.00 0.78 2.74

0.12 0.09 4.98 0.09 7.33 90.03 237.15

117.75% 16.69% 21.01% 204.44% 28.15% 16.66% 12.31%

0.00 0.04 0.00 0.00 0.00 0.60 7.49

0.19 0.66 0.00 0.00 0.00 0.08 0.18

PASS PASS PASS PASS PASS PASS PASS

ENN A ENN A1 3AcDON 15ACDON NIVAF G2AF B2 AF G1

Analysis 1

Analysis 2

Analysis 3

Analysis 4

Analysis 5

Analysis 6

Analysis 7

Analysis 8

Analysis 9

Analysis 10

Analysis 11

Analysis 12

Median

σ(anal)

σ(an)/(σ(H-Th)/2)

=> expected RSD(averages(2subsamples))

observed RSD (averages(2subsamples))

RSD(av.2 subs. 5g) / (0.3 σ(H-Th))

observed RSD (all subsamples)

RSD(50g, expected)

RSD(50g, expected) / (0.3 σ(H-Th))

s(sampling, bag) (%)

F1

F2

s(allowable) (µg/kg)

s(analyt) (µg/kg)

s(sam) (µg/kg)

c (= F1 σall 2 + F2 san 2)

(sqrt(c), as %)

s2sam

s(sam)/sqrt(c)

PASS ? (s2 sam < c ?)

Inj 1 Inj 2 Inj 1 Inj 2

246.0 243.4 24.3 17.9

228.3 214.9 17.1 21.7

237.2 248.8 27.5 19.4

230.2 272.7 21.4 32.6

255.6 254.4 16.9 17.0

258.6 260.4 24.2 18.4

217.1 271.3 20.2 18.1

192.6 227.7 25.1 22.4

242.8 250.7 22.6 23.0

206.8 210.7 20.8 21.4

246.0 213.2 23.9 22.9

235.9 229.9 24.5 20.2

240.0 21.6

7.74% 16.98%

1 2

5.47% 12.01%

7.39% 12.58%

1.24 1.91

8.75% 16.86%

2.77% 5.33%

0.46 0.81

4.97% 3.75%

1.83 1.83

0.93 0.93

14.16 1.44

18.39 3.70

11.80 0.82

681.65 16.48

10.98% 18.65%

139.30 0.66

0.45 0.20

PASS PASS

CITFUS X

Analysis 1

Analysis 2

Analysis 3

Analysis 4

Analysis 5

Analysis 6

Analysis 7

Analysis 8

Analysis 9

Analysis 10

Analysis 11

Analysis 12

Median

σ(anal)

σ(an)/(σ(H-Th)/2)

=> expected RSD(averages(2subsamples))

observed RSD (averages(2subsamples))

RSD(av.2 subs. 5g) / (0.3 σ(H-Th))

observed RSD (all subsamples)

RSD(50g, expected)

RSD(50g, expected) / (0.3 σ(H-Th))

s(sampling, bag) (%)

F1

F2

s(allowable) (µg/kg)

s(analyt) (µg/kg)

s(sam) (µg/kg)

c (= F1 σall 2 + F2 san 2)

(sqrt(c), as %)

s2sam

s(sam)/sqrt(c)

PASS ? (s2 sam < c ?)


8.9 Annex 8: Differences between the draft report and the final report

No changes were made to the draft report.

pt multi-mycotoxin coda-cerva 2017 final report …...coda-cerva 2017 multimycotoxin pt final report...

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