Laser Induced Breakdown Spectroscopy technique for detection of major elements in Particulate Matter from in-use Diesel engine passenger vehicles.

Abstract

Successful applications of laser-induced breakdown spectroscopy (LIBS) for the elemental analysis of Particulate Matter from In-Use Diesel Engine Passenger Vehicles have been performed. A 532 nm Nd: YAG laser was used to create the plasma plume, and five channel HR 2000 spectrometer covering the wavelength range from 200-720 nm was used to record the spectra of the plasma plume. By using the online NIST database, the spectral lines are detected. The Boltzmann equation and the Stark broadening line profile were used to determine the electron temperature and number density before the quantitative analysis. The Boltzmann plot was drawn using spectral lines that were free of self-absorption, and the slope of the line was used to determine the electron temperature. The Stark broadening effect was employed to calculate the electron number density, and Voigt fitting was used to calculate the entire width at half maximum for the Stark broadened line. The quantitative analysis was performed using the calibration-free method which revealed that Ca and Fe are the major elements present in the Particulate matter sample. The concentration of other elements like Na, Li, Mg and Ni are also present in the Particulate matter sample.