AUTHOR(S) / АУТОР(И): Aleksandar Piperevsk, Biljana Balabanova
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DOI: https://doi.org/10.46793/SBT26.857P
ABSTRACT / САЖЕТАК:
Soil organic carbon (SOC) is a key indicator of soil health, fertility, and sustainability, influencing nutrient cycling, soil structure, and biological activity. This study validated a classical Walkley–Black titrimetric method for routine SOC determination under laboratory conditions. The method is based on wet oxidation of organic carbon using potassium dichromate in concentrated sulfuric acid, followed by back-titration of residual dichromate with standardized ferrous sulfate using diphenylamine as an indicator. Method validation included assessment of linearity, precision, accuracy, limit of detection (LOD), and limit of quantification (LOQ). Calibration was performed using glucose standards covering 0.1–3.0% organic carbon. A BIPEA certified reference soil was used to ensure traceability and evaluate trueness. Excellent linearity was obtained (R² = 0.999). Precision showed relative standard deviation values below 5%, while accuracy assessed by standard addition yielded recoveries of 99.3–100%, indicating negligible matrix effects. The calculated LOD and LOQ were 0.01% and 0.04% OC, confirming that the method is sufficiently sensitive, reliable, and cost-effective for routine SOC analysis in agricultural and environmental soils.
KEYWORDS / КЉУЧНЕ РЕЧИ:
soil organic carbon, Walkley – Black titration, soil analysis, method validation
ACKNOWLEDGEMENT / ПРОЈЕКАТ:
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