Comparison of methods for analyzing organic matter in organic materials

Resumo

Two methods (wet combustion and calcination at 550 ºC) for the determination of organic matter in organic materials were compared. Nine laboratories participated in the assay, using five organic materials (three composts and two substrates), analyzed in quadruplicate. The precision was evaluated by calculating the  repeatability and reproducibility, according to the COVENIN 2972-92 (ISO 5725-86) standard. No significant differences were found between methods, laboratories, or replicates, so it is assumed that the compared methods generate statistically equal results. The precision evaluated through repeatability and reproducibility was not dependent on the level of organic matter. The lower repeatability and reproducibility values obtained with the calcination method indicate that this analytical modality is more precise. The application of the calcination method is recommended because it is based on a fast, simple procedure, does not consume chemical reagents and does not generate toxic waste for the environment and health.

DOI:https://doi.org/10.56238/sevened2023.006-154