Online mercury determination by laser-induced breakdown spectroscopy with the assistance of solution cathode glow discharge

Abstract

The trace mercury in aqueous solution is determined by laser-induced breakdown spectroscopy (LIBS) under the assistance of solution cathode glow discharge (SCGD) system. The aqueous solution is converted to gas phase using high voltage DC discharge, and then the generated mercury vapor is cooled by gas-liquid separator to improve the concentration of mercury. Finally, a 1064 nm wavelength Nd: YAG laser is used to produce plasma. In the present experiment, the characteristic spectral line of Hg I 253.65 nm is selected for analysis, under the optimal conditions of LIBS, the influences of the acid anion, discharge current, sample flow rate and carrier gas flow rate are investigated. The temporal behavior of the electron temperature and electron number density are also investigated, the results show that the electron temperature decreases from about 10900 K to 8800 K with delay time from 200 ns to 6 μs, and the electron number density is on the orders of 10 17 and 10 18 cm -3 , and it decreases with delay time. The analytical performances of this method are evaluated under optimized conditions, the calibration curve of Hg is plotted based on the different concentrations measurement results, and the detection limit (LOD) of Hg is calculated to be 0.36 mgL -1 . By using this experimental configuration, the detection limit and sensitivity of Hg are improved to some extent. This method provides an alternative analytical method for measurement of trace mercury in water.

Semiquantitative analysis of mercury in landfill leachates using double-pulse laser-induced breakdown spectroscopy

“…Figure 2(a) shows a typical LIBS spectrum of the sample containing 1000 mg Kg −1 Hg acquired by the DP LIBS in the region 175-330 nm. According to the literature [22,24,25,26], the most used emission line for Hg analysis by LIBS is the atomic Hg (I) line at 253.65 nm, which is shown in the expansion in Fig. 2(b).…”

“…Fang and Ahmad [21] obtained a LOD on the order of 85 mg Kg −1 when analyzing the surface of a water sample. Recently, Zheng et al [22] obtained a LOD of 0.36 mg Kg −1 for Hg in aqueous solutions. As a result of these works, it appears that the LOD of Hg obtained by LIBS, especially in solid samples, still needs to be improved.…”

Improving the LIBS Quantitative Analysis of Unburned Carbon in Fly Ash Based on the Optimization of Reference Value

“…But, the whole process is time-consuming. LIBS has been applied as a potential technology for online measurement of UC content in FA because of its simple sample preparation and fast response. − …”

Enhancement of Laser-Induced Breakdown Spectroscopic Signals in a Liquid Jet with Glow Discharge

“…However, the three aforementioned discharge-assisted techniques were all applied to solid targets; comparatively, fewer investigations have been performed on liquid School of Physics, Key Laboratory of Materials ModiEcation by Laser, Ion and Electron Beams, Chinese Ministry of Education, Dalian University of Technology, Dalian, China samples. 18 In this work, a liquid jet with a needle-to-needle glow discharge has been developed and combined with laser breakdown to investigate its efficacy in enhancement of analyte emission signals. Specifically, emissions signals of Mg, Ca, Al, Li, Na, and K emission lines from liquid-jet plasma in the absence and presence of a supplementary air-supported glow discharge were measured and compared.…”