On the detection of heavy elements in the Euphorbia indica plant using laser-induced breakdown spectroscopy and laser ablation time of flight mass spectrometry

Abstract

In this paper, we have addressed the phytoremediation, the ability to absorb heavy metals, of the Euphorbia indica plant by detecting heavy metals in its roots, stem and leaves using laser-induced breakdown spectroscopy (LIBS) and laser ablation time-of-flight mass spectrometry (LA-TOF-MS). Since agricultural yields heavily depend on soil fertility, which is badly affected by industrial waste and heavy metals, they need to be maintained and improved using the fertilization process and by removing the heavy metals. The presence of chromium in the Euphorbia indica plant has been established from the optical emission spectra of its different parts using the standard LIBS analytical technique. The detection limit of the trace element was improved by applying an electric field (E) across the laser-produced plasma plume, which yields much-enhanced intensities of the emission lines. The spectral lines of the trace elements also appear, which were too weak to be detected in the spectra taken in the absence of the electric field. The plasma parameters such as electron number density and plasma temperature were estimated from the spectra recorded with and without the electric field. The compositional analysis was performed using calibration-free LIBS and laser ablation time-of-flight mass spectroscopy, which are in good agreement.