[The Detection of Heavy Metals in Soil with Laser Induced Breakdown Spectroscopy]

The elemental concentration of Cr contained in soil is measured with laser induced breakdown spectroscopy (LIBS). As the LIBS laser power, the laser wavelength is of 1 064 nm with pulse width of 8 ns and laser repetition frequency of 10 Hz in this experiment and Cr 427.4 nm is selected as the analytical line of LIBS. The experimental results show that the relative standard deviation (RSD) of the detected content of Cr is 12.1% at the delay time of 4.78 μs and the soil sample surface 1 mm behind lens focal point. The limit of detection (LOD) of LIBS is 2.01 ppm. The measured relative deviation between the measured value and the nature value is 5.15%. Because the LIBS has advantages such as lower LOD and higher detection precision, LIBS has a guiding significance to detect heavy metal in soil and to monitor environmental quality precisely and rapidly.