Rapid soil analyses of overburden material from historic mines with SNMS

Abstract

Plasma-based Secondary Neutral Mass Spectrometry (SNMS) is designed and usually used for depth-resolved determination of the elements in inhomogeneous samples. This report shows that it is also advantageous for the quantification of the total elemental inventory of granular material. As an example of such an application, the quantitative elemental analysis of soil samples from residues of three historic mines in Baden-Wurttemberg is presented. The results obtained with SNMS, using a high primary energy of Ep = 1340 eV, were compared to the concentrations measured by Atomic Absorption Spectroscopy (AAS) and X-Ray Fluorescence (XRF). A reasonable correspondence was found with a mean deviation between all three methods of about 50%. However, SNMS measurements of standard soils, without any matrix adaptation of the elemental sensitivities, exhibited mean deviations from the certified concentrations of only 20–30 wt% down to concentrations below 10–2 wt%. The advantages of SNMS against AAS and XRF are its simple sample preparation and the rapid detection of all elements in the analyzed material within some 10 min. In each of the three samples chromium, nickel, copper, zink and lead (only sample HS 64) were found in concentrations exceeding the limiting values of the German Sewage Sludge Ordinance (SSO).