SIST-TS CEN/TS 15479:2006

Fertilizers - Spectrophotometric determination of biuret in urea

This Technical Specification specifies a method for the determination of biuret in urea. The method is applicable to urea and urea-based fertilizers.

Düngemittel - Spektrometrische Bestimmung von Biuret in Harnstoff

Engrais - Détermination photométrique du biuret dans l'urée

La présente norme expérimentale spécifie une méthode pour le dosage du biuret dans l’urée. La méthode s’applique à l’urée et aux engrais à base d’urée.

Gnojila – Spektrofotometrijsko določevanje biureta v sečnini

General Information

• Status: Withdrawn
• Publication Date: 30-Nov-2006
• Withdrawal Date: 11-May-2009
• ICS: 65.080 - Fertilizers
• Technical Committee: KAT - Soil quality
• Current Stage: 9900 - Withdrawal (Adopted Project)
• Start Date: 11-May-2009
• Due Date: 03-Jun-2009
• Completion Date: 12-May-2009
• Mandate: M/335 - Standardization Mandate assigned to the CEN concerning the modernisation of the methods of anylysis of Fertilizers
• Ref Project: CEN/TS 15479:2006 - Fertilizers - Spectrophotometric determination of biuret in urea

Relations

• Replaced By: SIST EN 15479:2009 - Fertilizers - Spectrophotometric determination of biuret in urea
• Effective Date: 01-Jun-2009

Standards Content (Sample)

SLOVENSKI STANDARD
01-december-2006
*QRMLOD±6SHNWURIRWRPHWULMVNRGRORþHYDQMHELXUHWDYVHþQLQL
Fertilizers - Spectrophotometric determination of biuret in urea
Düngemittel - Spektrometrische Bestimmung von Biuret in Harnstoff
Engrais - Détermination photométrique du biuret dans l'urée
Ta slovenski standard je istoveten z: CEN/TS 15479:2006
ICS:
65.080 Gnojila Fertilizers
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL SPECIFICATION
CEN/TS 15479
SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION
September 2006
ICS 65.080
English Version
Fertilizers - Spectrophotometric determination of biuret in urea
Engrais - Détermination photométrique du biuret dans Düngemittel - Spektrometrische Bestimmung von Biuret in
l'urée Harnstoff
This Technical Specification (CEN/TS) was approved by CEN on 24 June 2006 for provisional application.
The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to submit their
comments, particularly on the question whether the CEN/TS can be converted into a European Standard.
CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS available
promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in parallel to the CEN/TS)
until the final decision about the possible conversion of the CEN/TS into an EN is reached.
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, Romania,
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
© 2006 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TS 15479:2006: 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.6
8 Procedure .6
9 Calculation and expression of the result .7
10 Precision.8
11 Test report .8
Annex A (informative) Results of the inter-laboratory tests .9
Bibliography .10

Foreword
This document (CEN/TS 15479:2006) has been prepared by Technical Committee CEN/TC 260 “Fertilizers
and liming materials”, the secretariat of which is held by DIN.
This document has been prepared under a mandate given to CEN by the European Commission and the
European Free Trade Association.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to announce this CEN Technical Specification: Austria, Belgium, Cyprus, Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden,
Switzerland and the United Kingdom.
1 Scope
This Technical Specification specifies a method for the determination of biuret in urea. The method is
applicable to urea and urea-based fertilizers.
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.
prEN 1482-2, Fertilizers and liming materials — Sampling and sample preparation — Part 2: Sample
preparation
EN 12944-1:1999, Fertilizers and liming materials — Vocabulary — Part 1: General terms
EN 12944-2:1999, Fertilizers and liming materials — Vocabulary — Part 2: Terms relating to fertilizers
(including corrigendum AC:2000)
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
In an alkaline medium in the presence of potassium sodium tartrate, biuret and bivalent copper form a violet
cupric compound. The absorbance of the solution is measured at a wavelength of about 546 nm.
5 Reagents
5.1 General
Use only reagents of recognized analytical grade and distilled or demineralized water, free from carbon
dioxide and ammonia (grade 3 according to EN ISO 3696:1995). The quality of the water is particularly
important in this determination.
5.2 Methanol
5.3 Sulfuric acid solution
c = approximately 0,05 mol/l
5.4 Sodium hydroxide solution
c = approximately 0,1 mol/l
5.5 Alkaline solution of potassium sodium tartrate
In a graduated one-litre flask, dissolve 40 g of sodium hydroxide in 500 ml of water and leave to cool. Add
50 g of potassium sodium tartrate (NaKC H O 4H O). Make up to the mark and leave standing for 24 h
4 4 6 2
before use.
5.6 Solution of copper sulfate
In a graduated one-litre flask dissolve 15 g of copper sulfate (CuSO 5H O) in 500 ml of water. Make up to the
4 2
mark.
5.7 Freshly prepared biuret standard solution
In a 250 ml graduated flask, dissolve 0,250 g of pure biuret in water. Make up to 250 ml. 1 ml of this solution
contains 0,001 g of biuret.
5.8 Indicator solution
In a graduated 100 ml flask, dissolve 0,1 g of methyl red in 50 ml of 95 % ethanol, make up to 100 ml with
water. Filter if any insoluble remain. This indicator is red in acid solution and yellow in alkaline solution.
6 Apparatus
6.1 Spectrometer or photometer
With filters with a sensitivity and precision to permit measures of less than 0,5 % factor of transmission to be
produced. The factor of transmission, T, is given by the following equation:
J
T = (1)
Jo
The opacity, O, is given by the following equation:
Jo
O= (2)
J
The absorbance, E, is given by the following equation:
E= logO (3)
The absorbance per unit of optical run, k, is given by the following equation:
E
k= (4)
s
The coefficient of specific absorbance, K, is given by the following equation:
E
K = (5)
ρ×s
Biuret can be purified
...