Investigation of the self-absorption effect using time-resolved laser-induced breakdown spectroscopy

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Materials Science

Background:

• Self-absorption significantly impacts the accuracy and stability of quantitative analysis in laser-induced breakdown spectroscopy (LIBS).
• Understanding the temporal dynamics of self-absorption is crucial for improving LIBS performance.
• Traditional time windows for LIBS analysis may not be optimal for minimizing self-absorption effects.

Purpose of the Study:

• To investigate the temporal evolution of self-absorption in LIBS.
• To establish a method for reducing the impact of self-absorption on quantitative analysis.
• To determine an optimal time window for minimizing self-absorption and enhancing analytical performance.

Main Methods:

• Established exponential calibration curves to analyze the temporal evolution of self-absorption.
• Investigated the underlying mechanism of self-absorption during plasma expansion.
• Analyzed the determination of manganese (Mn) in steel as a case study.
• Compared analytical performance at early (0.2-0.4 μs) and traditional (2-3 μs) time windows.

Main Results:

• Self-absorption effects were found to be minimal during the early stages of plasma expansion.
• The upper bound of linearity (C_int) for Mn in steel was significantly higher at 0.2-0.4 μs (2.000 wt. %) compared to 2-3 μs (0.363 wt. %).
• Quantitative analysis demonstrated superior accuracy and stability at the earlier time window (0.2-0.4 μs).

Conclusions:

• Early plasma expansion (0.2-0.4 μs) presents a simple and effective strategy to mitigate self-absorption in LIBS.
• Optimizing the time window for LIBS analysis can substantially improve quantitative accuracy and stability.
• This approach offers a practical method for enhancing the performance of LIBS for elemental analysis.