Soil serves as a linking component in ecosystems; because of its high sorption capacity, it retains various elements, regulates their transfer into natural waters, and controls their availability in the nutrient medium of plants. Determination of the content of mobile element species in soil relies on their extraction with an ammonium acetate buffer solution, which presents one of the most widely used extractants, followed by an analysis of the resulting extract. Experimental results demonstrate that matrix effects during the application of the ICP OES method can manifest themselves differently for different soil samples. Analysts can eliminate these effects by the fivefold dilution of the extract; however, some samples require higher dilution factors. The known certified procedures for determining mobile species describe various approaches to obtaining ammonium acetate extracts. Experimental data demonstrate the influence of analyte extraction schemes differing in the time of interaction between the soil aliquot and the extracting solution, mixing method, and the number of extraction stages. On average, after 24-h equilibration, twice as much of the mobile element species is extracted as after 1-h agitation of the suspension on a shaker. In addition, the extraction efficiency depends both on the nature of the specific analyte and on the soil under investigation.
Savinov et al. (Sun,) studied this question.