Determination of 17 Elements in Soil by Inductively Coupled Plasma Atomic Emission Spectrometry After Dissolution with Mixed Acid

The sample (0.250 0 g) was added into a Teflon crucible, and a few drops of water was added to wet the sample. Then 1.5 mL of nitric acid, 1.5 mL of hydrochloric acid, 3 mL of hydrofluoric acid and 1 mL of perchloric acid were added, and the crucible was covered with a lid and placed in the fume hood overnight. The Teflon crucible was placed on a temperature-controlled electric heating plate, and heated at 190-210 ℃. The solution was evaporated until the white smoke was exhausted, and the power was turned off. 5 mL of hydrochloric acid (1+1) solution and 2 drops of hydrogen peroxide were added. The residual temperature of the hot plate was used to continue to dissolve the solid salt, and the crucible was heated further for 5-10 min until the solution was clear. After cooling, the solution was made up to 25.0 mL with water and let stand still for 3 h. Inductively coupled plasma atomic emission spectrometry was used to simultaneously determine 17 elements, such as sulfur, bismuth, antimony, cobalt, copper, lithium, manganese, nickel, strontium, barium, vanadium, zinc, magnesium, potassium, calcium, sodium and iron in the sample solution. Linear relationships were found between emission intensity and mass concentration of the 17 elements in definite ranges, and the detection limits were in the range of 0.02-50 μg·g^-1. The method was applied to the determination of the above 17 elements in the national standard materials of soil, giving the results consistent with the certified values, and the relative standard deviations (n=12) of the measured values less than 4.0%.