Laser-Induced Breakdown Spectroscopy (LIBS)

Introduction of Laser-Induced Breakdown Spectroscopy (LIBS)

Spectroscopic technique LIBS is an optical emission technique that utilizes a focused laser beam to interact with a material’s surface. The surface leads to the evaporation of a small part of the contact material between the laser pulse and the high temperature, generating plasma. As this plasma cools, atoms and ions release light that includes some wavelengths that are based on the elements involved. Since the wavelength of these emission lines can be measured using a spectrometer, LIBS can determine and measure the number of elements with great sensitivity. It is a candidate to change traditional wet chemistry or XRF analysis, which has the ability to analyze complex or odd materials due to its portability and capacity, eliminating the need for physical contact with materials to analyze.

Methodology of Laser-Induced Breakdown Spectroscopy (LIBS)

The laser beam (usually ND: YAG) used in a specific LIBS analysis focuses on the surface of a sample. The laser exposes a small piece of the light sample, carries the energy away, and produces plasma plumes that emit light. This light is gathered over optical fibers and propagated to a spectrometer, which separates and records the emission spectra. These spectral lines are later compared to a reference library for both qualitative and quantitative analysis. LIBS may be executed on air or in a controlled atmosphere or even in a vacuum background, and can be tailored to single-shot or multi-shot analysis requirements, depending on the sensitivity and depth profiling demanded.

Instrumentation of Laser-Induced Breakdown Spectroscopy (LIBS)

The typical LIBS constraint comprises a pulsed lamp (typically a Q-switched Nd: YAG laser), focusing optics, a plasma collection system, a spectrometer (usually having an ICCD or CMOS detector), and a computer with spectral processing software. Others are handheld and incorporated into drones or robotic arms or used in distant or unsafe areas. High-end LIBS systems are sometimes equipped with gated detectors or imaging systems or combined with other methods, such as Raman or XRF, to provide complementary analysis.

Strengths of Laser-Induced Breakdown Spectroscopy (LIBS)

LIBS provides real-time and multi-elemental analysis with minimized sample preparation. It can analyze both non-conductive and conductive materials, performing effectively on irregular surfaces and those with coatings. It is flexible and easy to use and can be applied in the field, during the process, or at the site. It is also non-destructive and non-hazardous to the environment, involving no reagents or consumables; it can render depth profiling and spatial mapping.

Limitations of Laser-Induced Breakdown Spectroscopy (LIBS)

Although LIBS is quick and adaptable, there are possibilities that it is limited as a high-precision detector of light elements (such as H, C, N, and O). The calibration process may not be straightforward due to matrix effects, and quantitative analysis may require complex algorithms or internal standards. There is also a small portion of the sample analyzed by LIBS, and this can be of concern depending on the sensitivity or value of the specimen. To properly obtain reproducible and accurate results, the use of high-resolution instrumentation and setup is essential.