Effect of soil matrix on elemental analysis using laser-induced breakdown spectroscopy (LIBS)
- Los Alamos National Lab., NM (United States)
Laser-induced breakdown spectroscopy (LIBS) has been demonstrated for chemical analysis of various solid materials. Nd-YAG laser pulses focused on the solid surface results in the generation of a laser plasma which vaporizes and ionizes a small amount of the solid material. Emissions from neutral and ionized atoms in the laser plasma are spectroscopically analyzed and the composition of the sample is determined from the elemental emission intensities generated by the plasma. LIBS has also been shown to provide a rapid quantitative elemental analysis of gases, liquids, and aerosols as well. Quantitative analysis of significantly more complex samples such as glasses and soils by LIBS depends on the ability to calibrate the method and to account for differences between the calibration standards and the real-world samples due to matrix effects. In this work, the effect of the chemical form of chromium and lead on LIBS measurements has been investigated. Analytical figures of merit include: detection limits, accuracy, and precision. Addition of these elements as liquid and solid compounds to matrices of soil and soil simulants have been used to evaluate matrix effects and to generate calibration curves. Univariant and multi-variant techniques were used to develop calibration curves and to study interelement correlation of spectral intensities. The experimental apparatus used was similar to those typically used for laboratory-based LIBS measurements. In this work, the authors focused 150 mJ/pulse Nd-YAG laser pulses on soil and soil simulants at normal incidence using a repetition rate of 10 Hz. The plasma light was collected by a fiber optic cable and directed onto the entrance slit of a 1 m-focal-length spectrograph. The emission spectra were recorded by a gated, intensified photodiode array.
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 273552
- Report Number(s):
- CONF-960113--
- Country of Publication:
- United States
- Language:
- English
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