BS EN 16964:2018 pdf download.Fertilizers – Extraction of total micro-nutrients in fertilizers using aqua regia
1 Scope
This European Standard specifies a method for the total extraction of boron, cobalt, copper, iron,manganese, molybdenum and zinc with aqua regia from mineral fertilizers containing one or more micro-nutrients.
The extracts can be analysed according to EN 16963, EN 16965, prEN 17041, prEN 17042 and prEN 17043.
This method is also suitable for the extraction of cadmium, chromium, nickel and lead to be determined according to EN 16319; the extraction of mercury to be determined according to EN 16320 and the extraction of arsenic to be determined according to EN 16317.
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一Vocabulary一Part 1: General terms
EN 12944-2, Fertilizers and liming materials and soil improvers一Vocabulary 一Part 2: Terms relating to fertilizers
EN 16963, Fertilizers 一Determination of boron, cobalt, copper, iron, manganese, molybdenum and zinc using ICP-AES
EN 16965, Fertilizers 一Determination of cobalt, copper, iron, manganese and zinc using flame atomic absorption spectrometry (FAAS)
EN ISO 3696, Water for analytical laboratory use一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.
8.3 Extraction
Moisten the test portion (8.2.1 or 8.2.2) with about 0,5 ml to 1,0 ml of water (6.1) and add, while mixing, 21 ml of hydrochloric acid [6.2) followed by 7 ml of nitric acid (6.3) drop wise if necessary to reduce foaming. Connect a condenser to the reaction vessel and let the mixture stand at laboratory temperature until any effervescence almost ceases. Transfer to the heating device and slowly raise the temperature of the reaction mixture to reflux conditions and maintain for 2 h ensuring that the condensation zone is lower than 1/3 of the height of the condenser. Then allow to cool and rinse the condenser with 10 ml of water (6.1). For samples with a micro-nutrient content of≤10 % transfer quantitatively into a 150 ml volumetric flask and dilute to the mark with water. The test solution corresponds to a 50 times dilution of the sample. For samples with a micro-nutrient content of> 10 % transfer quantitatively into a 500 ml volumetric flask and dilute to the mark with water. The test solution corresponds to a 500 times dilution of the sample. Test solutions may be filtered or centrifuged if necessary. Use ash-free filter paper of recognized and tested quality (7.3) and discard the first portion of the filtrate (approximately 20 ml).