SIST EN 16109:2012
(Main)Fertilizers - Determination of complexed micro-nutrient ions in fertilizers - Identification of lignosulfonates
Fertilizers - Determination of complexed micro-nutrient ions in fertilizers - Identification of lignosulfonates
This document specifies two complementary methods (method A and method B) that allow lignosulfonates to be indentified as soluble complexing agents in fertilizers.
Düngemittel - Bestimmung der in Düngemitteln komplexgebundenen Spurennährstoffionen - Identifizierung von Ligninsulfonaten
Dieses Dokument legt zwei komplementäre Verfahren (Verfahren A und Verfahren B) fest, die die
Identifizierung von Ligninsulfonaten als lösliche Komplexbildner in Düngemitteln ermöglichen.
ANMERKUNG Als Komplexbildner ist Ligninsulfonat ein natürliches Polymer, das in der Papierindustrie als Nebenprodukt
im Sulfitverfahren bei der Herstellung von Papier aus Holzzellstoff entsteht. Als natürliches Polymer stellt es eine
nicht genau festgelegte und veränderliche chemische Struktur dar. Es ist eine komplexe Mischung von klein- bis
mittelgroßen polymeren Verbindungen mit Sulfonatgruppen, die an das Molekül gebunden sind, und mit unterschiedlichem
Komplexbildungsvermögen.
Die Verfahren gelten für EG-Düngemittel entsprechend der Verordnung (EG) Nr. 2003/2003 [1].
Engrais - Dosage des oligo-éléments complexés dans les engrais - Identification des lignosulfates
Le présent document spécifie deux méthodes complémentaires (méthode A et méthode B) permettant d’identifier les lignosulfonates comme agents complexants solubles dans les engrais.
NOTE Le lignosulfonate, en tant qu’agent complexant, est un polymère naturel obtenu comme sous-produit de la fabrication du papier à partir de pâte de bois par la méthode au sulfite de l’industrie papetière. En tant que polymère naturel, il présente une structure chimique variable et mal définie. C’est un mélange complexe de composés polymères de petite à moyenne taille avec des groupes sulfonate liés à la molécule et présentant diverses capacités complexantes.
Les méthodes sont applicables aux engrais CE concernés par le Règlement (CE) n° 2003/2003 [1].
Gnojila - Določevanje ionov kompleksno vezanih mikrohranil v gnojilih - Identifikacija lignosulfonatov
Ta dokument določa dve dopolnilni metodi (metoda A in metoda B), ki omogočata identifikacijo lignosulfonatov kot kompleksirajočih reagentov v gnojilih.
General Information
Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Düngemittel - Bestimmung der in Düngemitteln komplexgebundenen Spurennährstoffionen - Identifizierung von LigninsulfonatenEngrais - Dosage des oligo-éléments complexés dans les engrais - Identification des lignosulfatesFertilizers - Determination of complexed micro-nutrient ions in fertilizers - Identification of lignosulfonates65.080GnojilaFertilizersICS:Ta slovenski standard je istoveten z:EN 16109:2011SIST EN 16109:2012en,fr,de01-februar-2012SIST EN 16109:2012SLOVENSKI
STANDARD
SIST EN 16109:2012
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 16109
November 2011 ICS 65.080 English Version
Fertilizers - Determination of complexed micro-nutrient ions in fertilizers - Identification of lignosulfonates
Engrais - Dosage des oligo-éléments complexés dans les engrais - Identification des lignosulfonates
Düngemittel - Bestimmung der in Düngemitteln komplexgebundenen Spurennährstoffionen - Identifizierung von Ligninsulfonaten This European Standard was approved by CEN on 1 October 2011.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre:
Avenue Marnix 17,
B-1000 Brussels © 2011 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 16109:2011: ESIST EN 16109:2012
EN 16109:2011 (E) 2 Contents Page Foreword .31Scope .42Normative references .43Terms and definitions .44Sampling and sample preparation .45Method A: Determination of phenolic hydroxyl content and 232,5 nm absorption for the identification of lignosulfonates .46Method B: Determination of organic sulfur content for the identification of lignosulfonates .87Expression of the results . 118Precision . 129Test report . 13Annex A (informative)
Statistical results of the inter-laboratory test . 14A.1General . 14A.2Test Samples . 14A.3Inter-laboratory test procedure . 14A.4Results and statistical interpretation. 14Bibliography . 17 SIST EN 16109:2012
EN 16109:2011
(E) 3 Foreword This document (EN 16109:2011) has been prepared by Technical Committee CEN/TC 260 “Fertilizers and liming materials”, the secretariat of which is held by DIN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by May 2012, and conflicting national standards shall be withdrawn at the latest by May 2012. This document has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. SIST EN 16109:2012
EN 16109:2011 (E) 4 1 Scope This document specifies two complementary methods (method A and method B) that allow lignosulfonates to be indentified as soluble complexing agents in fertilizers. NOTE Lignosulfonate, as a complexing agent, is a natural polymer produced as a by-product of the sulfite method for manufacturing paper from wood pulp in the paper industry. As a natural polymer, it presents a poorly defined and variable chemical structure. It is an intricate mixture of small- to moderate-sized polymeric compounds with sulfonate groups attached to the molecule, and diverse complexing capacity.
The methods are applicable to EC fertilizers covered by Regulation (EC) No 2003/2003 [1]. 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, 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 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. 5 Method A: Determination of phenolic hydroxyl content and 232,5 nm absorption for the identification of lignosulfonates 5.1 Principle The method for the determination of the phenolic hydroxyl content is based on the ultraviolet absorption of phenols in alkaline solution (phenolate). The absorbance of an alkaline solution of the sample is measured directly against an acid solution of the same sample. The phenolic hydroxyl content of the sample is calculated from the molar extinction coefficient maximum of the resulting curve and the molar extinction coefficient of reference compounds determined in the same way. SIST EN 16109:2012
EN 16109:2011
(E) 5 The determination of the absorption at 232,5 nm is normally considered the method for the quantification of lignosulfonates, providing that no other ultraviolet absorbing organic compounds are present.
NOTE For additional information see [3] and [4]. 5.2 Apparatus Usual laboratory equipment, glassware, and in particular the following: 5.2.1 Magnetic stirrer. 5.2.2 Balance, capable of weighing to an accuracy of 1 mg. 5.2.3 Filter paper for qualitative analysis, pore size 15 µm to 20 µm.1
5.2.4 pH-meter, equipped with a glass electrode. 5.2.5 UV-Vis spectrophotometer, equipped with 1 cm quartz cells. 5.3 Reagents 5.3.1 General a) reagents shall be of recognized analytical grade; b) water used for the preparation of sample solutions shall conform to EN ISO 3696, grade 2 and free of organic contaminants. 5.3.2 Hydrochloric acid solution, c(HCl)= 6 mol/l. 5.3.3 Sodium hydroxide solution, c(NaOH)= 0,1 mol/l. 5.3.4 Analytical grade fine mesh strong cation exchange resin 2
Styrene/DVB type, 8 % crosslinked. Hydrogen form. Functional group: sulphonic acid. Nominal exchange capacity: 1,7 mmolc/ml. Mesh: 50 to 100.
5.4 Procedure 5.4.1 Preparation of stock solution Weigh, to the nearest 1 mg, 0,15 g to 0,20 g of the sample in a 100 ml beaker. Add 4 g of cation exchange resin (5.3.4) and about 20 ml to 25 ml of water. Allow the ion-exchange process to take place for 20 min, ensuring proper mixing by means of a magnetic stirrer.
1)
Albet 412 filter paper or equivalent is an example of suitable product commercially available. This information is given for the convenience of users of this European Standard and does not constitute an endorsement by CEN of this product. 2) Biorad AG 50 W-X8 (50-100) Cat. No. 142-1431 is an example of suitable product commercially available. This information is given for the convenience of users of this European Standard and does not constitute an endorsement by CEN of this product. SIST EN 16109:2012
EN 16109:2011 (E) 6 Filter (5.2.3) into a 250 ml volumetric flask to remove the resin and thoroughly wash the filter. Dilute to the mark with water (stock solution). 5.4.2 Solution A (acid) Take an aliquot (40 ± 5 ml) of the stock solution into a 100 ml beaker and adjust pH between 2,0 and 2,2 with few drops of hydrochloric acid solution (5.3.2). Pipette 5 ml of the pH-adjusted solution into a 50 ml volumetric flask and dilute to the mark. Final concentration 0,06 g/l to 0,08 g/l. 5.4.3 Solution B (basic) Pipette 5 ml of the stock solution into a 50 ml volumetric flask. Add 10 ml of sodium hydroxide solution (5.3.3) to adjust pH over 11,0. Dilute to the mark. Final concentration 0,06 g/l to 0,08 g/l. Check that the pH of the solution is over 11,0, if not prepare solution B adding more sodium hydroxide. 5.4.4 Solution C Pipette 10 ml of the stock solution into a 100 ml beaker and fill with water to 60 ± 5 ml. Adjust the pH of the solution between 4,0 and 5,0 with the sodium hydroxide solution (5.3.3). Transfer quantitatively into a 100 ml volumetric flask, dilute to the mark with water and homogenize. See 5.4.6. 5.4.5 Measurement of phenolic hydroxyl content Fill both cells in the UV spectrophotometer with water. Enter background correction. Scan from 340 nm to 220 nm to check baseline. Fill the sample cell with solution B (5.4.3), and the reference cell with solution A (5.4.2). Scan from 340 nm to 220 nm. Rinse cells with water. 5.4.6 Measurement of 232,5 nm absorption Fill the sample cell with solution C (5.4.4), and the reference cell with water and record absorbance at 232,5 nm. The absorbance of the final solution should be between 0,2 and 0,8 to minimize deviations from Beer's Law instrumental error. If necessary, the volume to be taken from stock solution (5.4.1) to prepare solution C (5.4.4) should be adapted. 5.5 Calculation 5.5.1 Phenolic hydroxyl content Plot the spectrum in terms of absorbance. Record wavelength and absorbance for the maximum peak at 240 nm to 260 nm and for the minimum on either the right or the left side of the maximum. Subtract minimum absorbance from the maximum height (ûAbsmax) (see Figure 1). SIST EN 16109:2012
EN 16109:2011
(E) 7
Figure 1 — Example of the spectrum of solution B against A for the determination of phenolic hydroxyl content of a lignosulfonate showing the maximum and the minimum
(in this case at the left side) absorbances Calculate the phenolic hydroxyl content, wph, of the sample, expressed as mass fraction in percent using the ûAbsmax value of the sample and an average û0max value for reference compounds (8 867,5 l·mol-1·cm-1) by the following formula: 1000100117×∆×××∆=maxmaxphεdmAbsw (1) 525050×=d (2) where m
is the mass of the test portion in grams; d
is the dilution factor included in 5.4.1, 5.4.2. and 5.4.3, in millilitres; ûAbsmax is the value obtained subtracting the minimum from the maximum absorbance; 17
is the number of OH mol molOHgOH17; û0max is the average molar extraction coefficient for reference compounds (8 867,5 l·mol-1·cm-1). 5.5.2 232,5 nm absorption as lignosulfonic acid content Calculate the 232,5 nm absorption as lignosulfonic acid content, wla, of the sample, expressed as mass fraction in percent, by the following formula: 105,232la×××=fmdAw (3) SIST EN 16109:2012
EN 16109:2011 (E) 8 Vd250100×= (4) where A232,5 is the absorbance recorded at 232,5 nm (5.4.6); m
is the mass of the test portion in grams; d
is the dilution factor in millilitres considering dilutions in 5.4.1 and 5.4.4; f
is the absorptivity of the lignosulfonic acid in l/g cm, f = 36,5; V
is the volume in millilitres used to prepare solution 5.4.4. 6 Method B: Determination of organic sulfur content for the identification of lignosulfonates 6.1 Principle Sulfur bound to the lignin backbone in lignosulfonate samples is commonly termed organic sulfur while the remaining sulfur is conveniently described as inorganic sulfur (free sulfur, bisulfite addition compounds, sulfates, sulfites, sulfides, thiosulfates and tetrathionates). The method is based on the oxidation of inorganic sulfur to sulfate with alkaline iodine and its determination as barium sulfate. The remaining compounds are oxidized with a nitric-perchloric acid mixture to destroy organic matter and convert the sulfonated sulfur to sulfate, which is then determined as barium sulfate. NOTE For additional information see [5].
6.2 Apparatus Usual laboratory equipment, glassware, and in particular the following: 6.2.1 Magnetic stirrer. 6.2.2 Balance, capable of weighing to an accuracy of 0,1 mg. 6.2.3 Filter paper for qualitative analysis, pore size 15 µm to 20 µm.3 6.2.4 Ashless filter paper for quantitative analysis, pore size 2,5 µm.4
6.2.5 Porcelain crucibles, resistant to 800 ºC. The crucibl
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