Ion Chromatographic Determination of SCN in Soils

Abstract

An ion chromatographic (IC) procedure designed to avoid interferences from both plant tissues and soluble soil organic materials was developed to measure SCN− in soil extracts. Ionic thiocyanate (SCN−) was extracted from 4 g of soil with 10 mL of 0.01 M CaCl2 and the concentration determined with suppressed IC in combination with conductivity detection. Extraction efficiency from six SCN−-amended soils averaged 94% for SCN− concentrations of 1.25–12.5 μg of SCN−/g of soil. Colorimetric determination of SCN− in soil extracts was comparable to IC at higher amendment rates but averaged only 67 % of the amount added with spikes of 1.25 μg of SCN−/g of soil. the IC method is compatible with infrared analysis of isothiocyanates when soil is extracted simultaneously with CaCl2 and CCl4. Various anions including S2−, S2O42−, SO32−, SO42−, S2O32−, and S4O62− do not interfere with SCN- quantification. © 1991, American Chemical Society. All rights reserved.