Determination of 24 Rare Elements in Soil by Inductively Coupled Plasma Mass Spectrometry with Four Acid Digestion

An analytical method for the determination of 24 rare elements such as europium (¹⁵³Eu) in soil by inductively coupled plasma mass spectrometry with four acid digestion was established. The interference of acid digestion system and digestion process on the determination of rare elements was discussed. The mass spectrometry interference was corrected by selecting the appropriate isotope to be measured and the correction equation of the interfering element was edited. The physical interference and matrix interference were removed by using the inlay technique and collision mode. Establish the concept of "main interference weight", analyze and screen the internal standard elements, and finally determine ¹⁸⁵Re and ¹⁹³Ir as internal standard elements. The linear correlation coefficients of the standard curves of 24 rare elements were all greater than 0.999, and the detection limits of the method was 0.001-2.9 mg·kg^-1. The precision and accuracy tests were carried out with 3 kinds of soil reference materials GSS-8, GSS-13, GSS-27. Values of RSDs (n=6) in the range of 0.80%-19%, and the recovery in the range of 75.0%-124%. The measured value of each element was within the range of authorized values. This method is suitable for popularization and use in the national network soil environmental quality survey and other related work and research.