ICP-MS Determination of 14 Inorganic Elements in Soil Using Dilute Acid Dissolution

The soil sample (0.100 0-0.200 0 g) was first digested for 2 h with 6 mL of 3-4 mol·L^-1 H₂O₂ solution, then the mixture was microwave digested under the condition of programmed temperature elevation. After cooling, 2 mL of 7 mol·L^-1 HNO₃ solution were added and the digestion was repeated under the same condition. Water was added to make the mass of solution attained to 10.0 g. After centrifugation, the supernatant was used for ICP-MS determination of 14 inorganic elements. Values of detection limits (3s) found for the 14 elements were in the range of 0.002 0-0.63 mg·kg^-1. A standard sample of soil was analyzed by the proposed method, giving results in consistency with the certified values. As shown by the result of PCA, Ni, V, Zn and Cd were found to be the characteristic elements in soil, and the regularity of change in mass concentrations of the characteristic elements may be taken as the fingerprints of soil sample. A study on the correlationship of the characteristic elements with the contents of organic matters showed that no significant correlation was observed.