Handling Interferences for Nutrient-, Metal- and COD Analysis – Experience Report

Collaborative Efforts to Improve Environmental Monitoring
Oral Presentation

Prepared by C. Prokisch, A. Leitzke
MACHEREY-NAGEL, MACHEREY-NAGEL, Neumann-Neander-Str. 6-8, Dueren, NRW, 52355, Germany

Contact Information: cprokisch@mn-net.com; +492421969166


For many years, nutrient removal is a well-established step on many sewage plants in Europe. N- and P- parameters are important values that need to be reported to the authorities against discharge permits. Common strategies to handle interferences for the Phosphat-Test, total-Nitrogen Test as well as TKN Test will be presented.
In photometric metal analysis, complex building reagents often interfere. This can become especially troublesome when analyzing discharges from electroplaters. Methods to bypass these interferences include “crack-sets” used for the digestion of such compounds.
In COD analysis, the most common interferences are particles and Chloride. Special homogenization procedures may be necessary to ensure reasonable quality of results. HgCl2 normally masks chloride; however, over the last years different attempts have been made to overcome the use of this poisonous reagent.
MACHEREY-NAGEL is a German company founded in 1911 that is the major competitor of HACH in Germany and large parts of Europe. This competition led to a comparably very modern installation base for instruments that provides huge benefits for the end-user. In the US, MACHEREY-NAGEL water analysis has so far not been available.