Determination of Selenium in Soil by Inductively Coupled Plasma-Mass Spectrometry with Aqua Regia Digestion in Water Bath

Abstract

OBJECTIVES With more and more attention being paid to selenium-rich products, the study on the determination of selenium content in soil has become more significant. The accurate determination is difficult due to the serious interference of the matrix effect and polyatomic ion when determining selenium in soil samples by inductively coupled plasma-mass spectrometry (ICP-MS). OBJECTIVES To establish a method for accurate determination of Se in soil. METHODS The content of selenium in soil samples was determined by ICP-MS with 50% aqua regia-boiling water digestion. Kinetic energy discrimination mode (KED) was adopted to eliminate mass spectrum interference, and the 103Rh element was selected as the internal standard for on-line addition to eliminate instrument signal drift. RESULTS The results of the analysis of certified soil standard materials were consistent with those of certified standard materials within the uncertainty. The results showed that the relative errors (REs) of this method were between -2.01% and 2.99%, the relative standard deviation (RSD) was less than 6.60%, the detection limit was 0.012μg/g, and the minimum quantitative detection limit was 0.048μg/g. The method was applied to analyze 20 soil samples, and the results were consistent with those obtained by national environmental protection standard HJ680-2013. Conclusion The study results are suitable for the determination of selenium in large numbers of soil samples from the geological industry.

Keywords

• water bath digestion
• soil
• selenium
• inductively coupled plasma-mass spectrometry
• kinetic energy discrimination