DETERMINATION OF THE METHOD DETECTION LIMITS FOR METALS EXTRACTABLE WITH AQUA REGIA IN SOIL SAMPLES OF CENTRAL GREECE

摘要

The accurate determination of method detection limits (MDLs) for Aqua Regia extractable metals in soil samples has been shown to be difficult because not only is it difficult to obtain a representative reference soil sample but also sample spiking is difficult. The use of reagent water as the reference matrix for the determination of MDL in soils does not reflect the matrix effect of real world samples. This paper proposes a comparative approach for determining MDLs for Aqua Regia extractable metals in soils by first comparing the MDL derived from environmental surface waters with the MDL estimated from the replicate analyses of real soil samples, before assigning a rational MDL values for use in soils. This comparative approach does not require spiking soil and provides more realistic MDL values than the reagent water-based MDLs because they reflect the matrix effect of soils. The assigned MDL is verified using the relative standard deviation (RSD) obtained from the analysis of soils of different textures.