prEN 15477

SLOVENSKI STANDARD
01-junij-2015
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Fertilizers - Determination of the water-soluble potassium content
Düngemittel - Bestimmung von wasserlöslichem Kalium
Engrais - Détermination de la teneur en potassium soluble dans l'eau
Ta slovenski standard je istoveten z: prEN 15477
ICS:
65.080 Gnojila Fertilizers
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
DRAFT
NORME EUROPÉENNE
EUROPÄISCHE NORM
March 2015
ICS 65.080 Will supersede EN 15477:2009
English Version
Fertilizers - Determination of the water-soluble potassium
content
Engrais - Détermination de la teneur en potassium soluble Düngemittel - Bestimmung von wasserlöslichem Kalium
dans l'eau
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee CEN/TC 260.

If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations which
stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other language
made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United
Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are aware and to
provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice and
shall not be referred to as a European Standard.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2015 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 15477:2015 E
worldwide for CEN national Members.

Contents Page
Foreword .3
1 Scope .4
2 Normative references .4
3 Terms and definitions .4
4 Principle .4
5 Reagents .4
6 Apparatus .5
7 Sampling and sample preparation .5
8 Procedure .5
8.1 Test portion .5
8.2 Preparation of the aliquot part for precipitation .6
8.3 Weighing the crucible .6
8.4 Precipitation .6
8.5 Filtering and washing .6
8.6 Drying and weighing .6
8.7 Aliquot parts to be taken as samples and conversion factors .7
8.8 Blank test .7
8.9 Control test .7
9 Calculation and expression of the result .7
9.1 Dilution according to Table 1 .7
9.2 Dilution different from Table 1 .8
10 Precision .8
10.1 Inter-laboratory test .8
10.2 Repeatability .8
10.3 Reproducibility .8
11 Test report .9
Annex A (informative) Results of the inter-laboratory tests . 10
Bibliography . 11

Foreword
This document (prEN 15477:2015) has been prepared by Technical Committee CEN/TC 260 “Fertilizers and
liming materials”, the secretariat of which is held by DIN.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 15477:2009.
The following changes have been made to the former edition:
a) alternative amount of 1 g test portion taken into account in the case that the fertilizer contains more than
3 % of sulfur (S) and more than 4 % of calcium (Ca);
b) selection of apparatus extended by drying oven, boiling water bath and pipettes and graduated
measuring cylinders of different capacities;
c) editorial revised.
1 Scope
This document specifies a method for the determination of water-soluble potassium, which is applicable to all
potassium fertilizers listed in Annex I of the Regulation (EC) No 2003/2003 [3].
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
EN 1482-2, Fertilizers and liming materials — Sampling and sample preparation — Part 2: Sample
preparation
EN 12944-1:1999, Fertilizers and liming materials and soil improvers — Vocabulary — Part 1: General terms
EN 12944-2:1999, Fertilizers and liming materials and soil improvers — Vocabulary — Part 2: Terms relating
to fertilizers
EN ISO 3696:1995, Water for analytical laboratory use — Specification and test methods (ISO 3696:1987)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 12944-1:1999 and EN 12944-2:1999
apply.
4 Principle
The potassium in the sample to be analysed is dissolved in water. After eliminating or fixing the substances
that might interfere with the quantitative determination, the potassium is precipitated in a slightly alkaline
medium in the form of potassium tetraphenylborate.
5 Reagents
Use only reagents of recognized analytical grade and distilled or demineralized water (grade 3 according to
EN ISO 3696:1995).
5.1 Formaldehyde, clear formaldehyde solution with a mass fraction of 25 % to 35 % formaldehyde.
5.2 Potassium chloride, p. a.
5.3 Sodium hydroxide solution, c = 10 mol/l.
Care should be taken to ensure that only potassium free sodium hydroxide is used.
5.4 Indicator solution.
Dissolve 0,5 g of phenolphthalein in ethanol at 90 % and make the volume up to 100 ml.
5.5 EDTA solution.
Dissolve 4 g of the dihydrated disodium salt of ethylenediaminetetraacetic acid in water in a 100 ml graduated
flask. Make up the volume and mix.
Store the reagent in a plastics container.
5.6 STPB solution.
Dissolve 32,5 g of sodium tetraphenylborate in 480 ml of water, add 2 ml of the sodium
...