The detection of nerve agent degradation products in different soil fractions using capillary electrophoresis with contactless conductivity detection

Abstract

The adsorption of various phosphonic acids in sand and loam was studied. Samples of both soil types were sieved into three different fractions according to particle size. The fractions used were in the range 0–100, 100–200 and 200–400 μm. The performance of the capillary electrophoresis equipped with contactless conductivity detection was investigated. The limit of detection for the phosphonic acids tested was in the range 0.11–1.4 ppm. Different isotherms were constructed for all adsorption curves. Adsorption was found to be higher in sand than in loam when the Langmuir adsorption isotherm was used. The adsorption of methylphosphonic acid was higher than that of other phosphonic acids due to the smaller molecular size of the former.

Keywords:

• adsorption
• capillary electrophoresis
• chemical warfare agents
• contactless conductivity detection
• soil fraction

Acknowledgements

We acknowledge the Estonian Science Foundation (Grant No. 7818) for financial support. We thank Edur Kuuskmäe for assistance with the preparation of CCD–CE equipment.