CEN/TR 15106:2005

SLOVENSKI STANDARD
01-december-2005
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Fertilizers - Determination of chelating agents EDDHA and EDDHMA by ion pair
chromatography - Comparison of non-standardized Lucena method with EN 13368-
2:2001
Düngemittel - Bestimmung der Chelatbildner EDDHA und EDDHMA mit
Ionenpaarchromatographie - Vergleich der nicht standardisierten Lucena-Methode mit
EN 13368-2:2001
Engrais - Détermination des agents chélatants EDDHA et EDDHMA par
chromatographie ionique - Comparaison entre la méthode Lucena non normalisée et la
norme EN 13368-2:2001
Ta slovenski standard je istoveten z: CEN/TR 15106:2005
ICS:
65.080 Gnojila Fertilizers
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL REPORT
CEN/TR 15106
RAPPORT TECHNIQUE
TECHNISCHER BERICHT
May 2005
ICS 65.080
English version
Fertilizers - Determination of chelating agents EDDHA and
EDDHMA by ion pair chromatography - Comparison of non-
standardized Lucena method with EN 13368-2:2001
Engrais - Détermination des agents chélatants EDDHA et Düngemittel - Bestimmung der Chelatbildner EDDHA und
EDDHMA par chromatographie ionique - Comparaison EDDHMA mit Ionenpaarchromatographie - Vergleich der
entre la méthode Lucena non normalisée et la norme EN nicht standardisierten Lucena-Methode mit EN 13368-
13368-2:2001 2:2001
This Technical Report was approved by CEN on 7 April 2005. It has been drawn up by the Technical Committee CEN/TC 260.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,
Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2005 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TR 15106:2005: E
worldwide for CEN national Members.

Contents page
Foreword .3
Introduction.4
1 Scope .5
2 Normative references .5
3 Test procedure for ring test A.5
4 Test procedure for ring test B.10
5 Final conclusion.17
Annex A (informative) Non-standardized method: "Fertilizers - Determination of Fe chelated by
the chelating agents EDDHA and EDDHMA in fertilizers by ion pair chromatography".18
Annex B (informative) Comments received from the participating laboratories and suggestions
of CEN/TC 260/WG 5 for improvement of the non-standardized method .27
Annex C (informative) Suggestions received from the participating laboratories of
CEN/TC 260/WG 5 after ring test B .29
Bibliography.30

Foreword
This document (CEN/TR 15106:2005) has been prepared by Technical Committee CEN/TC 260 “Fertilizers
and liming materials”, the secretariat of which is held by DIN.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN shall not be held responsible for identifying any or all such patent rights.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to announce this Technical Report: Austria, Belgium, Cyprus, Czech Republic, Denmark,
Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg,
Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and the
United Kingdom.
Introduction
European Regulation (EC) No 2003/2003 of the European parliament and of the Council of 13th October 2003
relating to fertilizers states that the synthetic commercial iron chelates shall be water soluble products
obtained by the chemical combination of iron with a chelating agent. The iron (Fe) chelated by each chelating
agent shall be declared on the label.
EN 13368-2:2001 specifies a method for the determination of EDDHA and EDDHMA by ion chromatography.
This method determines the amount of chelated iron in Fe-EDDHA and Fe-EDDHMA commercial products. A
ring test performed by CEN/TC 260, showed that reproducibility data were poor, possibly due to the low
number of participating laboratories.
Some laboratories used a non-standardized method [1], [2], based on ion-pair chromatography. This can be
performed using common chromatography equipment and some experiences [3] suggested that it can give
adequate reproducibility and repeatability data.
CEN/TC 260/WG 5 agreed to launch a new work item in order to compare the reproducibility, repeatability and
accuracy of the two methods (standardized and non-standardized). The aim being to develope a European
Standard for the non-standardized method if better results were obtained. The results of the first ring test (ring
test A) were not significant enough to confirm that the non-standardized method is better than the method
standardized in EN 13368-2:2001.
The comments of the participating laboratories (see Annex B) suggested that the non-standardized method
could be improved with some modifications which could then result in significant differences with respect to
EN 13368-2:2001.
For this reason, WG 5 decided to carry out a second ring test (ring test B) using the method with the
suggested modifications.
This Technical Report includes the results and conclusions from the two ring tests.
1 Scope
This Technical Report covers the results from two ring tests (A and B, see Introduction) to compare the
repeatability and reproducibility of the standardized method for the determination of EDDHA and EDDHMA by
ion chromatography (EN 13368-2:2001) with a non-standardized alternative method using ion-pair
chromatography ("Lucena-method", given in Annex A). This Technical Report also provides the results of an
univariate multifactorial ANOVA test and F-test for ring test A and F-test for ring test B to verify the
significance of the reproducibility and the repeatability data.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
EN 13368-2:2001, Fertilizers - Determination of chelating agents in fertilizers by ion chromatography - Part 2:
EDDHA and EDDHMA.
3 Test procedure for ring test A
3.1 Methods used in ring test A for the determination of chelating agents EDDHA and
EDDHMA by chromatography.
Both methods tested for the determination of EDDHA and EDDHMA are based on high performance liquid
chromatography.
The standardized method, based on ion chromatographyis is given in EN 13368-2:2001.
The non-standardized method, based on ion-pair chromatography is given in Annex A (without the
modifications presented in italics, which were only used for ring test B).
3.2 Test Samples
Four different samples were provided to all the participants. Two samples were commercial iron chelates in
solid form, one containing Fe-EDDHA and the other containing Fe-EDDHMA. The other two samples were
solutions prepared from commercially available standards.
3.3 Ring test A procedure
The test samples were sent to 15 private or official laboratories from seven countries of which only 14
provided results.
The participating laboratories were requested to carry out 2 replicate analyses of each sample according to
each method.
Table 1 shows the samples analysed by each participating laboratory.
Table 1 — Samples analyzed by each participant laboratory

LABOR STANDARDIZED METHOD NON-STANDARDIZED METHOD
ATORY
Commercial samples Solutions from Commercial samples Solutions from
(solid form) standards (solid form) standards
EDDHA EDDHMA EDDHAEDDHMAEDDHA EDDHMAEDDHA EDDHMA
1 x x x x x x x x
2 x x x x x x x x
3 x x x x x x x x
4 - - - - x x x x
5 - - - - x - x -
6 - - - - x x x x
7 x x x x x x x x
8 x x x x x x x x
9 x x x x x x x x
10 - - - - x x x x
11 x x x x - - - -
a
12 x x x x x x x x
13 - - - - x x x x
14 x x x x x x x x
15 - - - - - - - -
TOTAL 9 9 9 9 13 12 13 12
a
only one replicate was reported

NOTE Most of the laboratories which did not analyse samples by the standardized method did not have the
necessary equipment for the determination given in EN 13368-2:2001.
Test results, observations and remarks have been reported on the appropriate sheets.
3.4 Results and statistical interpretation of ring test A
3.4.1 General
Statistical calculations have been carried out using all the results, according to ISO 5725-2 [4].
Parameters of repeatability and reproducibility have been evaluated for each sample and method (mean value,
standard deviation of repeatability (s), standard deviation of reproducibility (s ), repeatability limit (r),
r R
reproducibility limit (R), relative standard deviation of repeatability (RSD ) and relative standard deviation of
r
reproducibility (RSD ).
R
3.4.2 Statistical results of ring test A
3.4.2.1 Repeatability and reproducibility
Table 2 shows the statistical results of the ring test for repeatability and reproducibility.
Table 2 — Statistical results for ring test A

Parameter STANDARDIZED METHOD NON-STANDARDIZED METHOD
Commercial samples Solutions from Commercial samples Solutions from
standards standards
(solid form) (solid form)
SAMPLE EDDHA EDDHMA EDDHA EDDHMA EDDHA EDDHMA EDDHA EDDHMA
Number of 9 9 9 9 13 12 13 12
laboratories
Number of 0 0 2 1 1 0 1 1
outliers
Number of 9 9 7 8 12 12 12 11
laboratories
after
elimination of
outliers
Mean value 3,04 4,58 24,47 25,31 3,09 g 4,28 24,04 26,49
mg/l Fe/100 g mg/l
gFe/100 g gFe/100 g mg/l g Fe/100 g mg/l
Repeatability 0,21 0,36 0,47 1,38 0,04 0,12 0,20 0,32
limit, r mg/l
gFe/100 g gFe/100 g mg/l mg/l g Fe/100 g g Fe/100 g mg/l
RSD , % 2,5 2,8 0,7 2,0 0,5 1,0 0,3 0,4
r
Repeatability 0,07 0,13 0,17 0,49 0,02 g 0,04 0,07 0,11
standard Fe/100 g mg/l
gFe/100 g gFe/100 g mg/l mg/l g Fe/100 g mg/l
deviation
s
r
Reproducibility 0,41 1,31 2,97 7,21 0,33 1,11 2,58 4,85
limit, R mg/l
gFe/100 g gFe/100 g mg/l mg/l gFe/100 g g Fe/100 g mg/l
RSD , % 4,8 10,2 4,3 10,2 3,8 9,2 3,8 6,5
R
Reproducibility 0,15 0,47 1,27 2,57 0,12 0,37 0,92 1,73
standard mg/l
gFe/100 g gFe/100 g mg/l mg/l gFe/100 g g Fe/100 g mg/l
deviation
s
R
Horwitz value 3,4 3,2 9,9 9,8 3,4 3,2 9,9 9,8
R
Horrat R index 1,43 3,22 0,44 1,03 1,12 2,88 0,38 0,67

3.4.2.2 Reproducibility and repeatability significance
The comparison of the reproducibility and repeatability between the two methods for each sample is given in
Table 3.
Table 3 — ANOVA test results for mean values by types of samples

PARAMETER Commercial samples Solutions from standards
(solid form)
SAMPLE EDDHA EDDHMA EDDHA EDDHMA
a a a a
Calculated F
21,83 9,04 5,57 19,15
(r)
Calculated F 1,58 1,40 1,32 2,21
(R)
Tabulated F 2,95 2,95 3,09 3,14
a
significant at α =0,05
3.4.2.3 Accuracy comparison
A univariant multifactorial ANOVA test has been developed for the comparison of the means to examine the
significance of the differences between the two test methods.
Table 4 — R- an r- values and their significance by types of samples

PARAMETER Commercial samples Solutions from standards
(solid form)
SAMPLE EDDHA EDDHMA EDDHA EDDHMA
Calculated F 139,24 8,82 95,44 274,42
(Fischer)
0,054 0,207 0,068 0,038
Significance α
3.5 Conclusions for ring test A
3.5.1 General
Laboratories have provided more results by non-standardized method than by EN 13368-2.
In this ring test more results have been obtained for the standardized method than were available in the ring
test carried out by CEN/TC 260 in the past. This gives a better estimate of the repeatability and reproducibility
data.
3.5.2 Repeatability and reproducibility
The non-standardized method shows better repeatability for all samples, even for the solid samples where the
complete procedure was applied (i.e. sample preparation and analytical determination). s is significantly lower
r
for the non-standardized method.
There are no significant differences regarding s between the two methods, but the tendency is that the non-
R
standardized method shows lower reproducibility values for all samples, even for the solid samples where the
complete procedure shall be applied (i.e. sample preparation and analytical determination).
3.5.3 Accuracy compar
...