Analysis of trace elements in complex matrices (soil) by Laser Induced Breakdown Spectroscopy (LIBS)

Abstract

Direct spectro-chemical analysis of trace elements in complex matrices like minerals and soil is usually difficult because of possible interference from the intense background spectrum of the major components generated in the plasma. Optimization of the Laser Induced Breakdown Spectroscopy (LIBS) technique is essential for routine analysis of such samples. In the present work, we have shown that low detection limits can be achieved for trace elements like copper, zinc, and calcium in soil samples by using high resolution echelle spectrographs coupled to the LIBS system, and eliminating the background by subtraction of a suitable matrix "blank" spectrum. It is also shown that the LOD (limits of detection) can be further reduced by suitable data processing techniques like signal addition from multiple lines provided by the wide-range echelle system and use of correlation function calculation with a pure element spectrum. The validity of our LIBS technique was confirmed by conventional Atomic Absorption Spectroscopy (AAS) analysis for the same analyte after pre-concentration.

Ultratrace potassium determination in plutonium oxide

“…Blank subtraction is not the same as background subtraction [11], where an additional intensity is measured off of the peak. Blank subtraction takes the intensity measured in a blank sample, which matches the matrix of the samples being analyzed, and subtracts the signal from that sample from all subsequent samples.…”

Effects of sample pretreatment and particle size on the determination of nitrogen in soil by portable LIBS and potential use on robotic-borne remote Martian and agricultural soil analysis systems

“…[33][34][35][36][37][38][39][40] Various methods of soil sample preparation have been developed to achieve the homogeneity required for LIBS analysis, including mechanical pressure, 41 grinding and sieving 42 and a combination of these. 39,[43][44][45] However, these potentially may be difficult to replicate in a eld setting, especially using an autonomous rover analytical platform.…”

Homogeneity testing and quantitative analysis of manganese (Mn) in vitrified Mn-doped glasses by laser-induced breakdown spectroscopy (LIBS)

“…Detailed steps of these experiments to increase the signal strength and detection efficiency for plasma spectroscopy are discussed in our previous studies. 4,5 Influence of laser intensity (irradiance) on the plasma generation was studied using glass sample as a target at different incident laser intensities. This is achieved by the use of neutral density filters kept before the focusing lens.…”

“…Laser Induced Breakdown Spectroscopy (LIBS) as an analytical technique has grown spectacularly in the past few years to the extent that it is now being used even in remote analysis in the Mars mission confirming its experimental maturity. [2][3][4][5][6][7][8][9] The concept of LIBS relates to the interaction of a focused high power laser beam with matter, inducing the plasma on the surface of the matter and recording the atomic emission spectra from the plasma. The irradiation with high power laser pulses (usually nanosecond time scale) leads to material ablation and formation of plasma.…”