Resumo

GARCIA GALVIS, Johnbrynner  e  BALLESTEROS GONZALEZ, María Inés. QUALITY PARAMETERS EVALUATION FOR ORGANIC CARBON DETERMINING IN SOILS. Rev.Colomb.Quim. [online]. 2005, vol.34, n.2, pp.201-209. ISSN 0120-2804.

The organic carbon quantification in soils by the Walkley-Black method was studied using two analytical techniques (colorimetry and volumetry) to evaluate quality parameters of each one and point out the most convenient technique to be implemented in soil analysis. It was determined a linear interval, for sucrose, from 5 to 50 mg/mL with a maximum absorption wave length of 585 nm for reduced chromic acid. The comparison of the two quantifying methods showed systematic errors in the evaluated sucrose concentration levels (high, medium and low) for the volumetric method, whereas for the colorimetric method the quantification was more acurrate and the standard deviation values and variation coefficients were lower, which indicates that the last one is the most precise method. Moreover, the two methodologies were implemented with different soils and these results indicated that colorimetric method was less expensive and showed more repetibility in organic carbon quantification.

Palavras-chave : organic carbon; Walkley-Black method; soils; quality parameters.

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