Soil nutrient testing has seen many technological advances in last couple of decades which enable the analyst to quickly and accurately measure multiple soil nutrients at the same time. SGS uses Inductively Coupled Plasma-Optical Emission Spectroscopy (ICAP-OES) as the analytical process of choice for soil nutrient testing. In order to optimize high sample through-put using ICAP-OES, a two level quality control process is necessary. 

The first level of quality control is used to monitor the measuring and extraction processes that take place prior to instrument analysis. At this level, soil samples with known nutrient values are prepared along with the client samples. These known soil samples are inserted into the batches of soil that are being prepared for analysis. The final test results of these known samples provide valuable information to the analyst. Consistent test results are positive indicators for the soil preparation and extraction process. Variations in the “known” soil data can indicate problems with any of the preparation steps leading up to the instrument analysis. Liquid control samples with known values are analyzed directly at the ICAP-OES level to provide the second level of quality control. Prior to sample testing, the ICAP will calibrate and analyze the liquid control. Results from this liquid control must pass parameters that have been set into the program by the analyst. Results that fall outside the acceptable parameters can indicate issues with the auto-sampler or the instrument. Acceptable results signal the instrument to begin analysis of the soil sample extracts. The ICAP will then analyze the liquid control at set intervals throughout the testing process to assure instrument function.

Each level of this soil testing process needs to be monitored in order to provide quality soil nutrient test results. High through-put laboratories generate large volumes of data. Instrument manufacturers are now beginning to provide statistical programs that manage quality control data. They are also developing a greater menu of program options that better accommodate the varied needs of ICP-OES test methods.

For more information or to see how these process can help you, please contact:

April Holme
Toulon Lab Manager
t: (309) 286-2761

About SGS

The SGS Group is the global leader and innovator in inspection, verification, testing and certification services. Founded in 1878, SGS is recognised as the global benchmark in quality and integrity. With 59,000 employees, SGS operates a network of over 1,000 offices and laboratories around the world.