Investigation of the Effect of Target Water Content on a Laser-Induced Plasma

Abstract

Because of difficulties with matrix matching in a number of laser solid sampling techniques, plasma diagnostics are often employed directly or indirectly (through internal standardization) as a means of generating working curves. In this study, the effects of water content of CaCO3 powder on size, shape, excitation temperature, electron number density, continuum emission, and line emission of plasmas generated on the powder are investigated. Although the specific wetting properties of the matrix will determine the magnitude of the water content effects, the observations made for CaCO3 powder indicate that emission and electron number density are the two parameters affected significantly by water content, both decreasing with increasing weight % water. In laser-induced breakdown spectroscopy of samples that may have an inhomogeneous distribution of water or of samples in which water content can vary significantly, accounting for the effects of this water is essential to an accurate analysis.

Effects of moisture content on coal analysis using laser-induced breakdown spectroscopy

“…The ablated mass (even the calculated dry-based mass) of the coal sample with higher moisture content was higher than that of the coal sample with lower moisture content. Together with the results of plasma temperature and electron density shown in Section 3.3, these findings should lead to higher line signal intensities for coal samples with higher moisture contents, thereby contradicting our observations in our experiment and in other experiments [18][19][20][21]. By observing the ablated coal samples carefully, we found more splashed particles attached on the surface for coal samples with higher moisture contents, as shown in Fig.…”

On-Line Sorting of Wood Treated with Chromated Copper Arsenate Using Laser-Induced Breakdown Spectroscopy

“…The detrimental effects of water content on LIBS-based analysis have been reported previously for CaCO 3 powers. 14 The use of additional laser pulse energy is expected to extend the ability to detect CCA treated wood for these two sample types. It is noted that the use of the 200 mJ per pulse laser resulted in a signi cant increase in sorting accuracy, notably with damp wood samples, as compared with preliminary experiments using a 50 mJ per pulse laser.…”

Application of laser-induced breakdown spectroscopy to the analysis of secondary materials in industrial production

“…Coarse-grained powders have been analyzed directly by LIBS without pressing the sample material into pellets or fi xing the powder on a supporting tape. Examples are powders of CaCO 3 , KBr (particle diameter up to 0.1 mm), and coal (Rusak et al , 1997;Oki et al , 2004;Liangying et al , 2005). Plate VIII (see color section between pages 278 and 279) shows optical photographs of the laser-induced plasma and the laser-induced ejection of particles from the loose Fe 2 O 3 powder target ).…”