An optimized calibration procedure for determining elemental ratios using laser-induced breakdown spectroscopy

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Geochemistry

Background:

• Laser-Induced Breakdown Spectroscopy (LIBS) is a powerful technique for elemental analysis.
• Traditional LIBS methods like calibration curves are sensitive to matrix effects, while calibration-free methods have theoretical limitations.
• A need exists for LIBS procedures that are accurate, robust against matrix effects, and require minimal sample preparation.

Purpose of the Study:

• To present a novel hybrid LIBS procedure named Optimized Calibration LIBS (OC-LIBS).
• To reduce matrix effects and improve accuracy in elemental ratio determination.
• To enable fast, in situ elemental analysis with minimal sample preparation.

Main Methods:

• Developed OC-LIBS, a hybrid approach combining empirical and theoretical LIBS frameworks.
• Calibrated the OC-LIBS procedure using 22 certified powdered reference samples with diverse rock types and elemental compositions.
• Calculated compositional ratios between Mg and Al, Ca, Fe, K, Na, Si, and Ti.

Main Results:

• Achieved a correlation coefficient (R²) of ≥ 0.91 between reference and calculated values.
• Obtained a median relative prediction error between 9.5% and 33% across diverse samples.
• Demonstrated total data processing times below 1 second, enabling real-time analysis.

Conclusions:

• OC-LIBS offers a robust and accurate method for determining elemental ratios using LIBS.
• The procedure effectively minimizes matrix effects and requires minimal sample preparation.
• OC-LIBS facilitates rapid, in situ elemental analysis, leveraging the full potential of LIBS technology.