David Mburu Ng'ang'a
2007 Participant
Investigating the Factors influencing the Precision and sensitivity of Laser-Induced breakdown Spectroscopy Analysis
Laser-induced breakdown spectroscopy (LIBS), an atomic emission spectrometric technique, was first introduced by Brech in 19621. Since then LIBS has been evolved and successfully applied in elemental analysis of samples in gaseous, liquid and solid phases. LIBS involves the use tightly focused, pulsed, high-energy laser beams to generate plasma on a sample surface. The resulting plasma materials, all vaporized, due to the high core temperatures within the plasma volume consist of energetic ions and electrons. As the atoms cool from the plasma- excited states, they emit light characterized of their wavelengths2. The light is collected by a gated intensified detector for spectrochemical analysis to determine the identity and amount of the elements.
The utility of LIBS compared to other atomic emission spectrometric technique has increased greatly due to the recent development of small, high resolution spectrometer as well as several other attributes of LIBS such as; inherent high sensitivity, in-situ analysis as little or no sample preparation is required, noninvasiveness and only small sample amounts are required4. Our study is focused on establishing reproducible results for the higher repetition laser in an attempt to ascertain if the LIBS technique can be as reliable as other rival atomic emission spectrometric techniques. As noted earlier LIBS measurements are generated from laser plasma excitation, therefore, factors that affect laser properties influence the analytical properties of LIBS. To establish the reproducibility of the LIBS measurements we will focus on how physical variables such as laser energy, shot to shot fluctuation, detector gate delay time and use of background correlation affects the precision and accuracy of LIBS.