Determination of the limit of detection by X-ray photoelectron spectroscopy for As, Zn and Pb oxides in SiO2 matrix as model systems for environmental investigations

In this work the detection limits of arsenic, zinc and lead in silica matrix by x-ray photoelectron spectroscopy (XPS) analysis were evaluated. These elements were selected since they are particularly relevant in environmental investigations. Pure oxides and several binary mixtures with silica at different concentrations of As (III), Zn (II) and Pb (II) oxides obtained by ball milling were analyzed by XPS. Inductive-coupled plasma optical emission spectroscopy (ICP-OES) was also exploited for determining their bulk concentration. The linear response of XPS intensity vs weighed (at%) was confirmed. Three different models were here applied to estimate the limit of detection (LOD) of arsenic, zinc and lead and the results were in good agreement. Under the experimental conditions here adopted, the calculated LODs (at%) of arsenic, zinc, and lead as pure oxides and in silica matrix were found to range between 0.1 and 0.3, between 0.04 and 0.1 and between 0.03 and 0.04 respectively.