金纳米与磁场作用下LIBS检测灵敏度改善研究

doi:10.3964/j.issn.1000-0593(2019)05-1599-05

Abstract
References
Related Citation (15)

Download: PDF (2512 KB)
Export: BibTeX | EndNote (RIS)

Abstract In order to enhance the intensity of emission spectra of laser-induced plasma, a method of combining magnetic field enhanced laser induced breakdown spectroscopy(LIBS) with nanoparticle enhanced LIBS (NELIBS) was proposed. 20 nm in diameter Au-nanoparticles(Au NPs) was deposited on the surface of the sample by thermal evaporation. Copper and brass were induced to breakdown by a pulsed Nd∶YAG laser (1 064 nm, maximum energy 200 mJ) at room temperature and under standard atmospheric pressure. Laser-induced breakdown of copper was performed respectively using conventional LIBS, magnetic field-enhanced LIBS, NELIBS, and combining of the magnetic field enhanced LIBS and NELIBS with changing laser energy of 30~110 mJ. The enhancement factor and SNR for Cu Ⅰ 521.8 nm were obtained and the enhancement mechanism was analyzed. Brass and copper were induced to breakdown under four different constrains in the same environment to detect trace elements in the sample. When Au NPs were precipitated on the surface of the sample or the sample precipitated with the Au NPs was put in a magnetic field, the characteristic line of Mg Ⅱ 279.569 nm was found in the spectrum of the copper sample and the characteristic line of Si 251.611 nm was found in the spectrum of the brass sample. The experimental results showed that applying a magnetic field alone or add the Au NPs on the sample surface can effectively enhance the spectral intensity of the plasma, but the enhancement effect is weaker than the combination of the two methods. Magnetic field confinement enhancement of the spectrum is weaker than that of NELIBS. When the NELIBS is combined with magnetic field enhanced LIBS, the highest enhancement factor is up to 14.3 (CuⅠ 521.8 nm) and increased by 28% and 59% compared to magnetic field-enhanced LIBS and NELIBS, respectively. In the four cases, when the laser pulse energy was gradually increased, the Lorentz force that was generated by the magnetic field to restrain the plasma reduced relatively due to the increased expansion intensity of plasma, at the same time, the enhancement effect of the Au NPs on the emission spectrum of the plasma was weakened, the line intensity decreased, and the enhancement factor of plasma gradually decreased and tended to be stable. The combination of NELLBS and magnetic field enhanced LIBS can not only effectively increase the emission line intensity of the plasma and improve SNR of spectral , but also trace elements that cannot be detected in the conventional LIBS due to the low intensity of the spectral line and large background noise can be detected, and the ability of LIBS to detect trace elements is significantly improved, and the limit of detection of trace elements becomes lower. The method of combining NELIBS with magnetic field enhanced LIBS has higher sensitivity and accuracy, providing a new idea for the enhancement method of laser induced breakdown spectroscopy. It has broad application prospects in this field.

Key words：Au-nanoparticles; Magnetic field; Enhancement factor; Trace elements

Received: 2018-03-26 Accepted: 2018-07-30

ZTFLH:

O657.3

Corresponding Authors: HAO Xiao-jian E-mail: 15536867445m@sina.com

Cite this article:

URL:

https://www.gpxygpfx.com/EN/10.3964/j.issn.1000-0593(2019)05-1599-05 OR https://www.gpxygpfx.com/EN/Y2019/V39/I05/1599