Soil & Specialty Fertilizer Analysis by Discreet Analyzers

Nik van Zuilen, Industrial Solutions, Thermo Fisher Scientific, Vantaa, Finland

The classical analysis methods used for soil and specialty fertilizer analysis has been Continuous Flow Analysis (CFA) techniques combined with Inductively Coupled Plasma (ICP) and manual meters for pH and conductivity.

Changing needs and requirements have led to the adaptation of Discrete Industrial Analysis (DIA) because of increased analysis speed, ease of use and relatively low cost per test to replace the CFA methods which require a lot more time, manpower and bring higher costs. Both techniques (CFA and DIA) work with color reactions but the nature of DIA provides a lot more flexibility and cost savings compared to CFA. Partly because of this the lab is also able to use the DIA more frequently for R&D work to develop additional methods.

The purpose of this study is to present an overview of the typical different parameters in soil analysis using discrete analysis as the measurement technique. More detailed information is shown of specialty fertilizer analysis using automated discrete industrial analyzer including electrochemical measurement (ECM) unit for the measurement of pH and conductivity. The parameters involve Nitrate, Ammonium, Phosphorus, Potassium and Urea. The study shows matrix effects, linearity, repeatability, reproducibility, limit of detection, precision and accuracy/spike recovery. Additional parameters to be added later are Chloride, Fluoride and other secondary elements.

The results show that the evaluated discrete analysis methods correlate well compared to CFA, providing the lab with more flexibility, speed of analysis and saving costs.