EN 16024:2011 – Fertilizers – Determination of 1H-1,2,4-triazole in urea and in fertilizers containing urea – Method using high-performance liquid chromatography
1 Scope
This European Standard specifies a method for the determination of triazole (TZ) in urea or in fertilizers containing urea in the presence of dicyandiamide or methylpyrazole respectively using high-performance liquid chromatography (HPLC).
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.
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 sample of fertilizer is dissolved in water or extracted with water. The triazole content is determined in the solution using reversed phase high-performance liquid chromatography with an electrochemical pulsed detector.
5 Reagents
Use only reagents of recognized analytical grade.
5.1 Water, distilled or demineralised, conductivity less than 0,5 mS/m, according to EN ISO 3696:1995,grade 3.
5.2 1H-1,2,4-triazole.
5.3 Triazole standard solution, ρ=1 g/l.
Weigh 1 g of triazole to the nearest of 0,1 mg into a 1 000 ml measuring flask. Dissolve with water, make up to the mark with water and mix well.
5.4 Acetonitrile, gradient grade.
5.5 Buffer solution.
Weigh 8,9 g of dipotassium hydrogen phosphate trihydrate and 35,93 g of potassium dihydrogen phosphate in a 1 000 ml measuring flask, add approximately 750 ml of water, dissolve in the ultrasonic bath and make up to the mark with water.
6 Apparatus
6.1 Analytical balance, measuring accuracy 0,01 mg.
6.2 Ultrasonic bath.
6.3 Syringe filter, for aqueous solutions; pore size 0,25 µm.
6.4 HPLC device.
6.5 Sampling issuing system.
6.6 Electrochemical detector.
Working electrode: gold,
Reference electrode: Ag+AgCl, 3 mol/l KCl.
6.7 Reversed phase HPLC separator column, e. g. C8 10 µm, 250 mm × 4 mm.
6.8 Laboratory glassware.
7 Sampling and sample preparation
Sampling is not part of the method specified in this document. A recommended sampling method is given in EN 1482-1.
Sample preparation shall be carried out in accordance with EN 1482-2.
EN 16024:2011 – Fertilizers – Determination of 1H-1,2,4-triazole in urea and in fertilizers containing urea – Method using high-performance liquid chromatography