BS EN 16962-2018 pdf free download.Fertilizers – Extraction of water soluble micro- nutrients in fertilizers and removal of organic compounds from fertilizer extracts
This European Standard specifies a method for the extraction of water soluble forms of boron, cobalt, copper, iron, manganese, molybdenum and zinc from mineral fertilizers containing one or more micro- nutrients and the procedure for removal of organic compounds from the water extracts.
The extracts can be analysed according to EN 16963, EN 16965, prEN 17041, prEN 17042, prEN 17043 and CEN/TS 17060.
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.
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 EN 16963, Fertilizers — Determination of boron, cobalt, copper, iron, manganese, molybdenum and zinc using ICP-AES
EN 16965, Fertilizers — Determination of cobalt, copper, iron, manganese and zinc using flame atomic absorption spectrometry (FAAS) pr
EN 17043, Fertilizers — Determination of molybdenum in concentrations ≤ 10 % using spectrometry of a complex with ammonium thiocyanate
EN ISO 3696, Water for analytical laboratory use — Specification and test methods (ISO 3696) 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
The micro-nutrients are extracted by shaking the fertilizer sample in water at (20 ± 2) °C. Extracts are acidified after the extraction to avoid hydrolysis. Organic matter is removed if necessary by boiling after addition of hydrogen peroxide.
5 Sampling and sample preparation
Sampling and sample preparation are not part of this Standard. A recommended sampling method is given in EN 1482-1 [2] and a recommended sample preparation method in EN 1482-2 [3].
6 Reagents All reagents shall be of recognized analytical grade and they shall have negligible concentration of the element to be determined if compared to the lowest concentration of that element in the sample solution.
6.1 Water for extraction, grade 2 according to EN ISO 3696, free from micro-nutrients.
6.2 Nitric acid 65 %, c(HNO 3 ) = 14,3 mol/l; ρ = 1,42 g/ml.
6.2.1 Diluted nitric acid solution, c(HNO 3 ) = 5 mol/l.
Add 350 ml of nitric acid (6.2) to 650 ml of water (6.1).
6.3 Hydrogen peroxide solution 30 % H 2 O 2 , ρ = 1,11 g/ml, free from micro-nutrients.
6.4 Hydrochloric acid 37 % HCl, c(HCl) = 12 mol/l, ρ = 1,18 g/ml.
6.4.1 Diluted hydrochloric acid solution, c(HCl) = 5 mol/l.
Add 420 ml of hydrochloric acid (6.4) to 580 ml of water (6.1).
7 Apparatus
If the boron content is to be determined it is recommended to minimize contact of all solutions with borosilicate glassware. Use suitable plastic or silica ware especially for extraction step and for removal of organic compounds. Glass volumetric flasks may be used for making up to volume but shall not be used for storage of extracts and solutions.
7.1 Shaker, rotary or horizontal eccentric shaker.
Shaking shall prevent any settling of the sample during extraction.
7.2 Electric hotplate, equipped with variable temperature control.
7.3 Extraction vessels, capacity 500 ml and 1 000 ml.
7.4 Filter paper, ash-free and of recognized and tested quality.
7.5 Beaker, capacity 100 ml.
7.6 Volumetric flasks, capacity 25 ml and 50 ml.
7.7 Watch glass.
8 Procedure
8.1 Preparation of the test solutions
8.1.1 Micro-nutrient content ≤ 10 %
For samples with a micro-nutrient content of ≤ 10 % weigh (5 ± 0,005) g of the prepared sample,transfer the sample quantitatively to a 500 ml extraction vessel (7.3) and add (250 ± 0,2) ml of water (6.1) at (20 ± 2) °C.
8.1.2 Micro-nutrient content > 10 %
For samples with a micro-nutrient content of > 10 % weigh (2 ± 0,002) g of the prepared sample, transfer the sample quantitatively to a 1 000 ml extraction vessel (7.3) and add (500 ± 0,5) ml of water (6.1) at (20 ± 2) °C.BS EN 16962 pdf download.