Determination of 10 Trace Elements in Soil by Inductively Coupled Plasma Mass Spectrometry with Argon Online Dilution

A method for the determination of 10 trace elements, including nickel, arsenic, molybdenum, cadmium, antimony, praseodymium, samarium, europium, lead and uranium, in soil by inductively coupled plasma mass spectrometry (ICP-MS) with argon online dilution was proposed. The dried soil sample (0.2 g) was placed into a beaker, and 15 mL of nitric acid, 5 mL of hydrofluoric acid and 5 mL of hydrochloric acid were added, and the mixture covered surface dish was digested at 180 ℃. After the sample was completely digested, 2-3 mL of perchloric acid was added, and the digestion solution was open at 150 ℃ for driving acid to dry or wet salt state, finally 2 mL of nitric acid was added to dissolve it. If residue was remained, appropriate amounts of nitric acid, hydrofluoric acid and perchloric acid were used for repeated digestion according to the digestion condition until the sample was completely digested. The obtained solution was transferred into a centrifuge tube, and the beaker was rinsed with water at least 3 times. The rinsing solution was collected in the above centrifuge tube, and its volume was made up to 25 mL with water. Argon online dilution mode was used, and flow rates of atomized gas and diluted gas were set at 0.602, 0.610 L·min^-1, respectively. As shown by the results, linear relationships between the mass concentrations of 10 elements and response value ratios of analytes to internal standards were found in definite ranges, with detection limits (3s) in the range of 0.000 6-0.12 μg·L^-1. Tests for accuracy and precision were made on the reference material for soil composition analysis (GBW 07456), and the determined value of each element was within the uncertainty range of the certified value, and RSDs (n=6) of the determined values were less than 4.0%.