AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Development of a Triggering-LIBS for Determination of Elemental Composition of Single Particles in Real Time
Kihong Park, HEESUNG LEE, Jihyun Kwak, Gwangju Institute of Science and Technology
Abstract Number: 298 Working Group: Instrumentation and Methods
Abstract The Laser Induced Breakdown Spectroscopy (LIBS) with an aerosol focusing system has been developed to measure elemental composition of atmospheric particles in a rapid manner. The LIBS uses a powerful laser and generates a microplasma to excite particles samples at the atmospheric pressure, resulting in specific emission lights depending on the elemental constituents of the sample when the excited state goes back to ground state. The emitted emission lines are then sent into a broadband spectrometer (LIBS2000+, Ocean Optics Inc., USA), and the LIBS spectra are analyzed for identification of elements and their quantification. The LIBS was successfully applied to determine a time-resolved behavior of heavy metals during Asian Dust or local pollution event in our previous studies (Park et al., 2009; Park et al., 2011). Although the previous studies provided useful insight into temporal characteristics of particles (~1hour average data after collection of particles on to substrate), a single particle detection was not achieved due to low hitting efficiency of particles by the free-firing laser. In this study, we employed a continuous wave laser (642nm, 35mW, Excelsior Laser, Spectra Physics Inc., USA) to find the exact time for a single particle to arrive at the laser focal point and to trigger the second Nd:YAG laser (1064nm, 155mJ/pulse, Surelite II-10, Continuum Inc., USA) to produce micro-plasma, leading to enhance the hitting of particles by the second laser. Various particles of size and composition were produced in the laboratory to evaluate the triggering-LIBS system. Preliminary data show that the particle hitting efficiency of the trigger-LIBS was significantly improved compared to the free-firing LIBS system.