Analysis of Total Mercury in Soils Using ICP-AES Compared to the Combustion Method

Abstract

Anthropogenic mercury pollution of soils poses risks to both the environment and human health. To provide researchers with analytical capabilities to quantify total mercury in soils using the equipment available in its analytical facility, the Analysis Service Unit of CIRAD has implemented a method proposed by Agilent. This method employs inductively coupled plasma atomic emission spectrometry (ICP-AES) combined with microwave-assisted extraction of elements soluble in aqua regia.

The selected spectroscopic analysis technique, based on a multimode sample introduction system (M-SIS) into the plasma of an ICP-AES, meets analytical needs while requiring minimal investment for laboratories already equipped with an emission spectrometer.

The results demonstrate good accuracy of the "Aqua Regia Extraction / ICP-AES/MSIS Analysis" method on various soil reference materials. Although the sensitivity of ICP-AES is lower than that of the dry combustion method—the reference method for quantifying mercury in solid matrices—the proposed method performs well beyond the quantification requirements for Hg in soils.

This method represents an excellent compromise between cost and analytical performance, enabling accurate assessments of mercury contamination in soils. It can also serve as a reference for other laboratories operating in similar contexts.