Laser-induced breakdown spectrometry (LIBS) is technically characterized by the atomic emission of laser-induced microplasma, and it is receiving attention and vigorous development in scientific research and industrial fields. As the ambient gas, argon has an important influence on the collision process of particles in the plasma evolution process, which determines the performance of LIBS technology analysis. It is of great significance to improve the LIBS technology and its application level to study the spectral characteristics of argon in depth with the spectroscopic diagnosis technology. This paper uses an echelle spectrometer to record time series spectral information to study the transient Ar plasma collision and decay process, including the radiation mechanism during plasma evolution and the time evolution characteristics of plasma electron number density and temperature. The results show that the spectrum is mainly composed of continuous at the initial stage of the interaction between laser and argon. After 0. 6 mu s, the spectrum is mainly composed of discrete transition radiation lines of argon atoms and ions. The evolution period of the argon atomic line is different from that of the ion line. The ion line is dominant in the delay time of 0 similar to 1.0 mu s, and the atomic line is dominant in the 1. 0 similar to 30 mu s. Using Stark broadening and Saha-Boltzmann curve equation, the electron number density and temperature of plasma excited by 60, 80 and 100 mJ pulsed laser energy are calculated. The plasma electron number density decays rapidly within 0. 2 similar to 2. 0 mu s delay time, and then decreases slowly during a longer delay time, reaching the same order of magnitude at about 4. 0 mu s. The plasma temperature (with 80 mJ laser energy) dropped rapidly from 18 000 K at the initial 0. 2 mu s to 13 000 K (2. 0 mu s), and slowly dropped to 12 000 K after 5. 0 mu s. In order to further verify and optimize the analytical performance of laser pulses for argon, the evolution of the signal-to-noise ratio of different characteristic spectral lines of argon with time was studied. The research results show that the argon atom line has a higher signal-to-noise ratio in the delay window of 2. 0 similar to 6. 0 mu s, and the argon-ion line has a higher signal-to-noise ratio in the delay window of 0. 1 similar to 1.0 mu s.

Total reflection X-ray fluorescence (TXRF) has been widely considered as an effective analytical tool for the analysis of a great variety type of polymetallic deposits, because it has many advantages of extremely high sensitivity, high accuracy, minor sample preparation, and the ability of multielement simultaneous analysis. Sample preparation is quite important for TXRF quantitative analysis. Since pretreatment factors, such as sample amount, dispersant type, sample particle size and sample physicochemical properties, are seriously impact the accuracy of results. Based on this reason, investigating an appropriate sample pretreatment strategy is fundamental for accurate assessment of strategic metal elements in polymetallic deposits. This review presents a comprehensive overview of TXRF applications in the field of mineral analysis, including apatite, manganese ore, K-feldspars, granite, copper-nickel sulfide ore, etc. Moreover, the accurate evaluation of TXRF quantitative analysis is detailedly discussed, and the relevant sample preparation methods and preparation factors are also addressed.

With the development of industrial technology, the requirements of online detection instruments and detection technology in gas detection are becoming higher and higher. Due to the complex changes in gas composition during gas flow, common detection methods such as Fourier Transform Infrared Spectroscopy (FTIR), Cavity ring-down spectroscopy (CRDS), and Electrochemical sensors often cannot meet the detection requirements or only Local area detection. Laser-induced breakdown spectroscopy (LIBS) , as an emerging atomic emission spectroscopy analysis technology, has received extensive attention and research from researchers in the field of spectral analysis. LIBS has been applied to detect solids, liquids and gases because of its advantages of simultaneous detection of multi-elements, non-invasive, real-time on-line and no special preparation of samples. LIBS technology can accurately detect in the fields of harsh environments and high interference gas manufacturing and detection. The present paper introduces the basic principle of LIBS technology and two parameters describing the physical properties of plasma. For the application of LIBS technology in the field of gas detection, This paper introduces the recent development of LIBS technology in the field of gas detection at home and abroad from the following six aspects : Fuel equivalent ratio, the gas composition of fuel mixture combustion products, nitrogen and a rare gas, greenhouse gas and new energy gas detection, as well as related LIBS experimental equipment and experimental methods improvement and optimization. Finally, the prospect of laser-induced breakdown spectroscopy in the field of gas detection has prospected.