BS ISO 19746:2017 pdf download.Determination of urea content in urea-based fertilizers by high performance liquid chromatography (HPLC)
This document specifies the test procedure for determining the urea content in urea-based fertilizers , including urea , urea aldehydes [methylene urea fertilizers , isobutylene diurea (18 0U ) , crotonylidene diurea (C OU) ], urea triazone fertilizers , urea a mmonium nitrate (UAN) , sulfur- and polymer-coated urea (SCU and PCU) , as weII as compound fertilizers containing urea.
The method is based on High Performance Liquid Chromatography (HPLC). The proposed method is an extens i on of the AOAC OfficiaI Method 20 03 .1 4 wh ich was coIIabor ative ly studied for the “Determination of Urea in Water-Soluble Urea-Formaldehyde Fertilizer Products an d in Aqueous Urea Solutions” in 2003.
The method was published in the J ournal of AOAC in and was granted the First Action in 2003 and the Final Action in 2008. This method aIso app lies to the determination of biuret content in ure a containing fertilizer with the results published in the J. AOAC in This method was adopted by the International Organization for Standardization (1 S0) as a Committee Oraft (ISOjCO 18643) in 2014 , and after review and the Ring Tes Analyses[6].
NOT E This HPLC method can also be utilized to analyse Crotony li dene diurea (C D U) and Isobutylidene diurea (I BD U) contents within those above-mentioned addition to EN
Normative references Z
The foIIowing docume n ts are referred to in the text in such a way th at some or a II of their content constitutes requirements of this document. Fo r dated re ferenc es , only the edit ion cited app lies. For undated references , the Iatest edition of the referenced document (including any amendmen t s) app lies.
ISO 3696:1995 , Water use – test methods
Terms and definitions 3
No terms and de f initions are listed in this document.
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Principles 4
T he urea content in urea-based fertilizer is extracted by aqueous acetonitrile mobile phase and separated from other contents by High Performance liquid chromatography (HPLC) on an aminopropyl column. The urea peak is detected by a UV detector attac h ed to the HPLC.
Reagents 5
WARNING – Acetonitrile is flammable and toxic , The related operations shall be performed in a laboratory fume hood . This document does not point out all possible safety problems , and the user shall bear the responsibility to take proper safety and health measures , and ensure the operations are compliant with the conditions stipulated by the related laws and regulations of
the state.
Use only water conforming to grade 3 of IS0 3696:1995.
5.1 Acetonitrile, LC grade.
5.2 Mobile phase, 150 ml water + 850 ml acetonitrile.
Filter the mobile phase solution using a 0,22 micron membrane and degas with nitrogen gas for 10 min as a pre-treatment before use.
5.3 Urea standard solutions, (0.5 mg/ml = 500 ppm).
Weigh 0,5 g of high purity urea, dissolve in mobile phase (5.2) and transfer into a 1 1 volumetric flask.
Dilute the solution to wolume with mobile phase (5.2) and mix thoroughly.
6 Apparatus
Ordinary laboratory apparatus and the fllowving equipment/instruments:
6.1 Ultrasonie bath.
6.2 High performance liquid chromatograph, with UV detector.
6.3 Microsyringe, 5 pI~50 pL.
6.4 Syringe-driven Filter, with organic filter membrane of 0,22 μm pores.
6.5 Injection loop, volume of 10μ山
6.6 Sieve, with the aperture size of 0,50 mm.
6.7 2,00 micron flter paper.
7 Procedures
7.1 Preparation of test sample
7.1.1 For dry urea frtlizers, simply take 500 g of a divided sample as the test sample. For compound frilizerse, take a reduced lab sample of 100 g grinding until it passes through a steve of aperture size 0,5 mm, and mix thoroughly for reasons of homogeneity. Place the sample in a clean and dry bottle with lid.
7.1.2. For liquid urea frtilizers, take 100 ml ofa homogeneous solution. Flter any particulate through 2,0 micron filter paper.
For all of these samples, use ultrasonic mixing for 10 min to assure complete dissolution. Filter to remove any undissolved portion through a 2,0 micron filter paper.BS ISO 19746 pdf download.BS ISO 19746:2017 pdf free download
