oSIST prEN ISO 15959:2019

Fertilizers - Determination of extracted phosphorus (ISO 15959:2016)

ISO 15959:2016 specifies a method for the determination of phosphorus in fertilizer extracts.
The method is applicable to all extracts of fertilizers for the determination of the different forms of phosphorus as phosphorus soluble in mineral acids, water soluble phosphorus, phosphorus soluble in solutions of ammonium citrate, phosphorus soluble in 2 % citric acid and phosphorus soluble in 2 % formic acid.

Düngemittel - Bestimmung von Phosphor in den Extrakten (ISO 15959:2016)

Engrais - Dosage du phosphore extrait (ISO 15959:2016)

La présente Norme internationale spécifie une méthode de dosage du phosphore dans des extraits d'engrais.
La méthode est applicable à tous les extraits d'engrais pour le dosage des différentes formes de phosphore telles que le phosphore soluble dans les acides minéraux, dans l'eau, dans des solutions de citrate d'ammonium, dans l'acide citrique à 2 % et dans l'acide formique à 2 %.

Gnojila - Določevanje ekstrahiranega fosforja (ISO 15959:2016)

General Information

• Status: Not Published
• Public Enquiry End Date: 03-Jul-2019
• ICS: 65.080 - Fertilizers
• Technical Committee: KAT - Soil quality
• Current Stage: 98 - Abandoned project (Adopted Project)
• Start Date: 20-Aug-2020
• Due Date: 25-Aug-2020
• Completion Date: 20-Aug-2020
• Ref Project: prEN ISO 15959 - Fertilizers - Determination of extracted phosphorus (ISO 15959:2016)

Relations

• Revised: SIST EN 15959:2012 - Fertilizers - Determination of extracted phosphorus
• Effective Date: 01-Jun-2019

Standards Content (Sample)

SLOVENSKI STANDARD
oSIST prEN ISO 15959:2019
01-junij-2019
Gnojila - Določevanje ekstrahiranega fosforja (ISO 15959:2016)
Fertilizers - Determination of extracted phosphorus (ISO 15959:2016)
Düngemittel - Bestimmung von Phosphor in den Extrakten; Deutsche und Englische
Fassung prEN ISO 15959:2018
Engrais - Dosage du phosphore extrait (ISO 15959:2016)
Ta slovenski standard je istoveten z: prEN ISO 15959
ICS:
65.080 Gnojila Fertilizers
oSIST prEN ISO 15959:2019 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN ISO 15959:2019

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oSIST prEN ISO 15959:2019
INTERNATIONAL ISO
STANDARD 15959
First edition
2016-07-15
Fertilizers — Determination of
extracted phosphorus
Engrais — Dosage du phosphore extrait
Reference number
ISO 15959:2016(E)
©
ISO 2016

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oSIST prEN ISO 15959:2019
ISO 15959:2016(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2016, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. [phone]
Fax [phone]
[e-mail]
www.iso.org
ii © ISO 2016 – All rights reserved

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oSIST prEN ISO 15959:2019
ISO 15959:2016(E)

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Sampling and sample preparation . 1
6 Reagents . 1
7 Apparatus . 2
8 Procedure. 3
8.1 Treatment of the solution . 3
8.2 Hydrolysis . 3
8.3 Weighing the crucible . 3
8.4 Precipitation . 3
8.5 Filtering and washing . 3
8.6 Drying and weighing . 4
8.7 Blank test . 4
8.8 Verification . 4
9 Calculation and expression of the result . 4
10 Precision . 5
10.1 Interlaboratory tests . 5
10.2 Repeatability . 5
10.3 Reproducibility . 5
11 Test report . 6
Annex A (informative) Statistical results of the interlaboratory test . 7
Bibliography . 9
© ISO 2016 – All rights reserved iii

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oSIST prEN ISO 15959:2019
ISO 15959:2016(E)

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment,
as well as information about ISO’s adherence to the World Trade Organization (WTO) principles in the
Technical Barriers to Trade (TBT) see the following URL: www.iso.org/iso/foreword.html.
ISO 15959 was prepared by CEN/TC 260 as CEN/TS 15959:2009 and was adopted (without modification
other than that stipulated below) by Technical Committee ISO/TC 134, Fertilizers and soil conditioners.
The following changes have been made:
— potassium dihydrogen phosphate has been added to the reagents (Clause 6);
— CEN/TS 15956, CEN/TS 15957 and CEN/TS 15958 have been updated to EN standards;
— other editorial changes.
iv © ISO 2016 – All rights reserved

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oSIST prEN ISO 15959:2019
INTERNATIONAL STANDARD ISO 15959:2016(E)
Fertilizers — Determination of extracted phosphorus
1 Scope
This International Standard specifies a method for the determination of phosphorus in fertilizer
extracts.
The method is applicable to all extracts of fertilizers for the determination of the different forms of
phosphorus as phosphorus soluble in mineral acids, water soluble phosphorus, phosphorus soluble in
solutions of ammonium citrate, phosphorus soluble in 2 % citric acid and phosphorus soluble in 2 %
formic acid.
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.
ISO 14820-2, Fertilizers and liming materials — Sampling and sample preparation — Part 2: Sample
preparation
EN 12944-1, Fertilizers and liming materials and soil improvers — Vocabulary — Part 1: General terms
EN 12944-2, Fertilizers and liming materials and soil improvers — Vocabulary — Part 2: Terms relating to
fertilizers
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 12944-1 and EN 12944-2 apply.
4 Principle
After possible hydrolysis, phosphorus is precipitated in an acid media in the form of quinoline
phosphomolybdate.
After filtering and washing, the precipitate is dried at 250 °C and weighed.
In the above mentioned conditions, no interfering action is exerted by the compounds likely to be found
in the solution (mineral and organic acids, ammonium ions, soluble silicates, etc.) if a reagent based on
sodium molybdate or ammonium molybdate is used in the precipitation.
5 Sampling and sample preparation
Sampling is not part of the method specified in this International Standard. A recommended sampling
method is given in ISO 14820-1.
Sample preparation shall be carried out in accordance with ISO 14820-2. Grinding of the laboratory
sample is recommended for homogeneity reasons.
6 Reagents
6.1 Water, distilled or demineralized.
© ISO 2016 – All rights reserved 1

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oSIST prEN ISO 15959:2019
ISO 15959:2016(E)

6.2 Concentrated nitric acid, p = 1,40 g/ml.
6.3 Preparation of reagents
6.3.1 Preparation of the reagent based on sodium molybdate
Solution A: Dissolve 70 g of sodium molybdate dihydrate in 100 ml of distilled water.
Solution B: Dissolve 60 g of citric acid monohydrate in 100 ml of distilled water and add 85 ml
concentrated nitric acid (6.2).
Solution C: Stir solution A into solution B to obtain solution C.
Solution D: To 50 ml of distilled water, add 35 ml of concentrated nitric acid (6.2), then 5 ml of freshly
distilled quinoline. Add this solution to solution C, mix thoroughly and leave standing overnight in the
dark. After this, make up to 500 ml with distilled water, mix again, and filter through a sintered glass
funnel (7.7).
6.3.2 Preparation of the reagent based on ammonium molybdate
Solution A: In 300 ml of distilled water, dissolve 100 g of ammonium molybdate while heating gently
and stirring from time to time.
Solution B: Dissolve 120 g of citric acid monohydrate
...