Correction of Matrix Effects in Quantitative Elemental Analysis With Laser Ablation Optical Emission Spectrometry

Normalization of laser-induced breakdown spectroscopy spectra using a plastic optical fiber light collector and acoustic sensor device

“…Laser plasma formation is a nonlinear process, and minor fluctuations in laser beam energy or sample properties can result in a large deviation of atomic line intensity in the spectrum. Among others, chemical and physical matrix effects between the different atomic species [4,5], shot-to-shot fluctuations of the laser pulse parameters (energy, duration, etc.) [6], influence of particles ejected from previous pulses [7], variations in the spatial shape of the plasma plume that affects the light collection efficiency of the spectrometer, and changes in surface conditions of the sample and the experimental setup and its environment in general have been identified as potential sources of errors in the quantitative sample evaluation [8].…”

“…One possibility is the acoustic wave generated by the plasma, as the laser pulse produces rapid vaporization of the material surface, and the expansion of the ablated vapor into the surrounding gas forms a shockwave that generates a sound. Although some works have found a complex relationship between the vaporized mass and the laser irradiance for large irradiance values due to the plasma shield effect [13], it is generally assumed that the intensity of the acoustic wave is linearly related to the laser irradiance, and therefore, it is a valid signal for normalization purposes [4,11,14,15]. Acoustic emission is usually detected with standard microphones in the human acoustic detection range, allowing measurement of the acoustic signal from distances up to several meters from the target.…”

Correction of self-absorption effect in calibration-free laser-induced breakdown spectroscopy by an internal reference method

“…In order to correct the matrix effect on the calibration curves, a number of methods have been proposed [15][16][17]. The procedure based on normalization with respect to a reference line can provide higher accuracy and reproducibility of the analytical results than methods using simple line intensity [15].…”

“…Panne et al propose a model which includes the equilibrium Saha and Boltzmann relationships to correct the pulse-to-pulse variability of the plasma electron temperature and density [16]. Chaleard et al describe the emission intensity of a line by using a model considering the electron temperature and total mass vaporized in the plasma plume [17]. In their experimental conditions, they demonstrated that the acoustic signal emitted by the plasma is proportional to the vaporized mass.…”

“…In their experimental conditions, they demonstrated that the acoustic signal emitted by the plasma is proportional to the vaporized mass. Therefore, a correction for the matrix effect was accomplished by measuring the vaporized mass and plasma temperature [17].…”