EN 16109:2011

Foreword
1 Scope
2 Normative references
3 Terms and definitions
4 Sampling and sample preparation
5 Method A: Determination of phenolic hydroxyl content
  and 232,5 nm absorption for the identification of
  lignosulfonates
6 Method B: Determination of organic sulfur content
  for the identification of lignosulfonates
7 Expression of the results
8 Precision
9 Test report
Annex A (informative) - Statistical results of the
       inter-laboratory test
Bibliography

This document specifies two complementary methods (method A and method B) that allow lignosulfonates to be indentified as soluble complexing agents in fertilizers.NOTELignosulfonate, 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].