BS EN 17042:2018 pdf download

BS EN 17042:2018 pdf download.Fertilizers – Determination of boron in concentrations> 10 % using acidimetric titration
1 Scope
This European Standard specifies a method for the determination of total and water extractable boron in mineral fertilizers containing more than 10 % boron.
This method is applicable to water and aqua regia fertilizer extracts obtained according to EN 16962 and/or EN 16964.
NOTE A method used for the determination of boron in mineral fertilizers containing less than or equal to 10 % of boron (spectrophotometric determination by azomethine-H) can be also used for the scope of this method after appropriate dilution of the extracts.
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 1482-2, Fertilizers and liming materials – – Sampling and sample preparation 一Part 2: Sample preparation
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 16962, Fertilizers- Extraction of water soluble micro-nutrients in fertilizers and removal of organic compounds from fertilizer extracts
EN 16964, Fertilizers一Extraction of total micro-nutrients in fertilizers using aqua regia
EN ISO 3696, Water for analytical laboratory use一Specification and test methods (ISO 3696:1987)
8 Procedure
8.1 Test solution
Place an aliquot [a) of the extract containing 2 mg to 4 mg boron into a 400 ml beaker (Z.3). Add 150 ml of water (6.1). Add several drops of the methyl red indicator solution (6.2). If necessary acidify by adding hydrochloric acid solution [6.3) up to the point of change of the indicator. Then add 3 g of sodium chloride (6.8), bring to boiling to drive off the carbon dioxide. Allow to cool. Place the beaker on the magnetic stirrer (7.2) and mix by using a PTFE rod [7.4). Insert the pre- calibrated pH meter electrodes [7.1) into the beaker and adjust the pH first approximately up to 5 with the 0,5 mol/l sodium hydroxide solution [6.4), then to exactly pH = 6,3 with the 0,025 mol/l sodium hydroxide solution (6.5). Add 20 g of D-mannitol [6.7), dissolve completely and titrate with the 0,025 mol/l sodium hydroxide solution (6.5) to pH 6,3 (at least 1 min stability). Let X1 be the volume of 0,025 mol/l sodium hydroxide solution (6.5) required.
8.2 Blank solution
Prepare a blank solution by repeating the whole procedure from the preparation of solution stage, omitting only the fertiliser. Let Xo be the volume of 0,025 mol/l sodium hydroxide solution (6.5) required.