Comparative analysis of analytical methods for the quantification of sulfates in reconstituted soil matrices: Effect of soil texture and interfering species

This article studies the effect of various soil textures on sulfate determination and compares the performance of ion chromatography and the turbidimetric method for quantifying sulfates in reconstituted soil matrices. The comparison is conducted under both interference-free conditions and in the presence of interferences, such as chlorides and fluorides. These interferences caused significant overestimations of theoretical sulfate concentrations when using the standardized turbidimetric method. For instance, at a theoretical sulfate concentration of 1000 mg/kg, the result obtained through the turbidimetric method was 12085.5 mg/kg in the presence of chlorides, while the result obtained through ion chromatography was 915.5 mg/kg. An alternative method relying on hyperspectral imaging is also presented for direct sulfate analysis in soil without the need for extraction. Hyperspectral analyses proved to enable rapid analysis and accurate prediction of sulfate concentrations in soil samples, with an R 2 score of 0.87 in the absence of interferences and an R 2 score of 0.9 in the presence of chlorides. • Ion chromatography and turbidimetry were compared for sulfate quantification. • The effect of soil texture on sulfate determination was studied. • Hyperspectral imaging determined sulfates in soil samples without extraction.