Selenium Quantification in Soil by LIBS

Laser-induced breakdown spectrometry (LIBS), known as an express analysis technique, is for the first time applied in this study for determining selenium in soil. Modern agriculture requires elemental analysis methods to perform the continuous automated online control of microelement content in soil. However, selenium has never been quantitatively determined in soil by LIBS so far. Different sample preparation techniques (loose soil powder, mounted on adhesive tape and tableted soil) are employed here for LIBS determination of selenium in soil. The optimal choice of analytical line is challenging for selenium because of spectral interference with the minor and major soil components (Fe, Si, Zn, Al, Sb), but the Se I 196.09 nm line has the lowest spectral interference. A limit of detection of 3 mg/kg for selenium in soil is achieved in the present study using LIBS. The analytical performance of tape-mounted and loose soil powder samples with appropriate data averaging is found to be comparable to that achieved for tablets.