ISO INTERNATIONAL STANDARD 25705 Firstedition 2016-04-01 Fertilizers Determination of urea condensates using high- performance liquid chromatography (HPLC) Isobutylidenediurea and crotonylidenediurea (method A) and methylen-urea oligomers (method B) Engrais - Dosage des condensats d'urée par chromatographie liquide haute performance (CLHP) Isobutylidene diurée et crotonylidene diurée (méthode A) et oligomeres de méthylene-urée (méthodeB) Reference number IS0 25705:2016(E) ISO International Organization for Standardization @ IS0 2016 STANDARDIZATIONC15956617 I without license from IHS IS0 25705:2016(E) COPYRIGHTPROTECTEDDOCUMENT IS02016,PublishedinSwitzerland All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form 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 copyrightoffice Ch. de Blandonnet 8 . CP 401 CH-1214 Vernier, Geneva, Switzerland Tel. +41 22 749 01 11 Fax +41 22 749 09 47 [email protected] www.iso.org Internatinair PrganizationforStandardization ensee-ZHEJIANG INSTOFSTANDARDIZAoISQ6- All rights reserved etworking permitted without license from IHS IS0 25705:2016(E) Contents Page Foreword ..iv Introduction. ..V 1 Scope. ..1 2 Normative references 3 Terms and definitions 4 Sampling and sample preparation .1 5 Method A: Determination of CDU and IBDU ..1 5.1 Principle. .1 5.2 Reagents... .1 5.3 Apparatus .2 5.4 .2 Procedure 5.4.1 System parameters of HPLC 2 5.4.2 Calibration 2 5.4.3 Preparation of the test portion 3 5.4.4 Measurement .3 5.4.5 Important annotations .3 5.5 Calculation .3 6 Method B: Determination of methylene-urea oligomers (MU) ..4 6.1 Principle. 4 6.2 Reagents .4 6.3 Apparatus. 6.4 Procedure .5 6.4.1 System parameters of HPLC .5 6.4.2 Calibration .5 6.4.3 Preparation of the test solution ..6 6.4.4 Measurement. 7 6.4.5 Importantannotations 6.5 Calculations. .7 7 Precision method A and method B 7.1 Inter-laboratory test. ...8 7.2 Repeatability ..8 7.3 Reproducibility ..8 8 Test report ..9 Annex A (informative) Results of the inter-laboratory tests ..10 Annex B (informative) Chromatogram and calibration curves method A ..12 Annex C (informative) Chromatogram and calibration curves method B ..14 Bibliography .17 iii e=ZHEJIANG INSTOF STANDARDIZATION C15956617 ense with ISt ed without license from IHS Not for Resale, 2016/7/20 02:49:33