Quantitative Analysis of Manganese in Underwater Steel Samples Using Long–Short Double-Pulse Laser-Induced Breakdown Spectroscopy

Abstract

The long–short double-pulse laser-induced breakdown spectroscopy (LS-DP-LIBS) method was applied to qualitative and quantitative analyses of underwater steel samples to improve the detection ability of underwater measurement. The stable plasma intensity and discrete emission lines were detected using LS-DP-LIBS when comparing the measured results of single-pulse LIBS (SP-LIBS) and LS-DP-LIBS. The long pulse produces a cavitation bubble without plasma, and the short pulse induces the plasma of steel samples within the bubble. The detection features of LS-DP-LIBS for underwater steel samples were discussed in different intra-pulse delay time, long-pulse width, and delay time conditions when analyzing the measured spectra, the signal intensity of Fe(I) at 400.524 nm and 402.187 nm, Mn(I) at 404.136 nm, and intensity ratio of Mn(I) 404.136 nm/Fe(I) 402.187 nm. The results indicated that the plasma stability and spectral signal intensity were improved significantly with a long-pulse width of 80 µs in the intra-pulse delay time of 70 µs, which were appropriate for bubble formation and plasma generation. According to the discussion of the delay time effect, the state of generated plasma was almost stable from 650 ns to 850 ns. Manganese (Mn) contents in steel samples were analyzed quantitatively when measuring five steel samples with different Mn contents using LS-DP-LIBS in optimal experimental conditions. A strong linear dependence was observed with R2=0.9842, which demonstrated the feasibility and appropriateness of quantitative analysis for underwater measurement using LS-DP-LIBS.

Atomic spectrometry update: review of advances in the analysis of metals, chemicals and materials

“…The other paper by that group compared the long-short double pulse version of LIBS with conventional single pulse LIBS. 22 The long-short double pulse version gave a better stability and this was attributed to the long pulse causing a cavitation bubble without a plasma and then the short pulse creating a plasma within the bubble. The LIBS parameters of intra-pulse delay time, long pulse width and delay time were optimised.…”

“…Two papers by the same research group have discussed the application of long-short, double pulse LIBS to the determination of Mn in underwater steel samples. 21,22 In the first example, by Cui et al , it was emphasised that underwater LIBS suffers from numerous problems including self-absorption effects, weak signal intensity and low lifetime of the signal. These could all be overcome using Fraunhofer-type lines.…”

Effect of repeated irradiation on laser-induced breakdown spectroscopy of copper immersed in a sodium chloride aqueous solution and normalization with bubble collapse time

“…On-site elemental analysis of submerged solids or dissolved species can be achieved by measuring the emission spectrum of the plasma produced by laser ablation (e.g., ref. [1][2][3][4][5][6][7] or laserinduced breakdown (e.g., ref. [8][9][10][11][12][13][14] in liquids.…”

Resolution effects on spectral analysis of low alloy steel by laser-induced breakdown spectroscopy

“…Qingdong et al found that the quantitative analysis accuracy of a fiberoptic LIBS system was slightly higher than that of a traditional LIBS system and a portable LIBS system [11,12]. Experimental parameters such as laser energy, delay time and resolution are also factors that researchers have often considered [13,[14][15][16]. Khater et al searched for stable conditions suitable for spectrochemical analysis by changing the laser energy [17].…”

“…Quantitative analysis is also an important research area in LIBS spectral analysis. Quantitative analysis is helpful to understand the concentration of elements in the material and is helpful for industrial analysis [13,23,24]. It is very important to study the influencing factors of quantitative analysis.…”