Ion, charge ratio

Nonspecific, depends mostly on the concentration ratios on the solid vs. the soil solution and on the ion charge ratio. Some clay minerals prefer one ion over others. 

The mass spectrum produced shows the relative abundance (isotopic abundance) on the vertical axis and the mass to ion charge ratio (m/e) on the horizontal axis. Figure 1.4 shows a typical mass spectrum for a sample of lead. Table 1.1 shows how the data is interpreted. 

---