[Comparative Study on Laser Induced Breakdown Spectroscopy Based on Single Pulse and Re-Heating Orthogonal Dual...

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Laser-Induced Breakdown Spectroscopy (LIBS)

Background:

• Improving the detection sensitivity and spectral characteristics of Laser-Induced Breakdown Spectroscopy (LIBS) is crucial for accurate elemental analysis.
• Traditional single-pulse LIBS often faces limitations in sensitivity and signal quality, especially for trace elements.

Purpose of the Study:

• To investigate the effectiveness of a re-heating orthogonal dual-pulse configuration in enhancing LIBS performance.
• To analyze the impact of dual-pulse parameters, specifically the time interval, on spectral intensity and signal-to-background ratio (SBR).
• To evaluate the improvement in detection limits for heavy metals, such as chromium, using this advanced LIBS technique.

Main Methods:

• Utilized a re-heating orthogonal dual-pulse LIBS setup to analyze samples containing iron (Fe), lead (Pb), calcium (Ca), and magnesium (Mg).
• Investigated the relationship between spectral intensity, SBR, and the time interval between the two laser pulses.
• Compared spectral intensity, plasma temperature, electron density, and detection limits under single-pulse and dual-pulse conditions.

Main Results:

• The optimal time interval for the dual laser pulses was determined to be 1.0 μs.
• Dual-pulse configuration resulted in enhancement factors of 2.23-2.42 for characteristic spectral lines and improved SBR.
• Plasma temperature increased by up to 730 K and electron density by 1.8×10^16 cm⁻³, while the detection limit for chromium was reduced by approximately two times (from 38 to 20 μg·g⁻¹).

Conclusions:

• The re-heating orthogonal dual-pulse LIBS technique significantly enhances spectral intensity and signal-to-background ratios.
• This method effectively prolongs spectral intensity decay time and improves overall detection sensitivity.
• The dual-pulse approach offers a valuable method for reducing elemental detection limits, particularly for heavy metals in environmental samples.