Breakthrough Study Introduces Statistical Definition to Enhance Calibration-Free Laser-Induced Breakdown Spectroscopy

Laser-induced breakdown spectroscopy (LIBS) is a highly efficient technique for elemental analysis, providing fast and reliable results. However, its usefulness in trace element analysis has been limited by the high limit of detection (LOD) associated with the method. Addressing this challenge, a groundbreaking study published in the journal Spectrochimica Acta Part B: Atomic Spectroscopy has introduced a statistical definition of the LOD, specifically designed for calibration-free LIBS (CF-LIBS), offering promising advancements in the field (1).

Red laser light | Image Credit: © Jürgen Fälchle - stock.adobe.com

CF-LIBS is a technique used for elemental analysis that does not require the construction of calibration curves or the use of reference materials (1). In CF-LIBS, the sample is directly ablated using a laser, generating a plasma plume (1). The emission spectra from the plasma plume are then analyzed to determine the elemental composition of the sample (1). Unlike traditional LIBS, CF-LIBS relies on statistical methods and algorithms to estimate the elemental concentrations based on the relative intensities of the spectral lines emitted by the plasma. This approach eliminates the need for time-consuming calibration procedures and allows for rapid and onsite analysis of samples (1). CF-LIBS has found applications where quick and accurate elemental analysis is required.

Authored by Paulino Ribeiro Villas-Boas and Luís Carlos Leva Borduchi from Embrapa Instrumentação in São Carlos, Brazil, the study recognizes the importance of accurate LOD determination for LIBS, particularly in the analysis of trace elements that play a vital role in various scientific and industrial applications (1).

In the research, the authors propose a statistical LOD definition for CF-LIBS, considering critical factors such as the density of emitters, plasma parameters, and measurement uncertainties (1). By considering the uncertainties associated with emission line intensities, estimated through the standard deviation of the background signal, the LOD in CF-LIBS can now be determined using a robust framework (1).

The proposed statistical LOD definition for CF-LIBS involves the propagation of uncertainties applied to CF-LIBS calculations and considers the dependence on plasma temperature and emission line properties (1). To validate the approach, the researchers conducted experiments using sodium chloride samples containing carbon and calcium (1). Remarkably, the LOD values obtained using the proposed definition were comparable to those acquired through LOD determination for calibration curves, highlighting the efficacy of the statistical approach (1).

This breakthrough study not only offers an enhanced LOD estimation method for CF-LIBS but also presents a comprehensive and reliable LOD definition for LIBS quantitative analyses (1). By incorporating statistical considerations and accounting for various parameters, researchers can now achieve more accurate and precise elemental analysis results, enabling advancements in fields such as environmental monitoring, geological exploration, and material science (1).

The findings of this study hold tremendous potential for the future of LIBS, empowering scientists and researchers to delve deeper into trace element analysis, uncover new insights, and make informed decisions based on robust and quantifiable data (1). With the statistical LOD definition for CF-LIBS, the limitations of high LOD values are being overcome, ushering in a new era of enhanced accuracy and sensitivity in laser-induced breakdown spectroscopy (1).

Reference

(1) Villas-Boas, P. R.; Borduchi, L. C. L. A statistical definition of limit of detection for calibration-free laser-induced breakdown spectroscopy. Spectrochim. Acta Part B At. Spectrosc. 2023, 205, 106690. DOI: https://doi.org/10.1016/j.sab.2023.106690