Analysis of single mass-regulated particles in precisely controlled trap using laser-induced breakdown spectroscopy

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Materials Science

Background:

• Laser-Induced Breakdown Spectroscopy (LIBS) is a powerful technique for elemental analysis.
• Analyzing single droplets and particles presents challenges in signal stability and detection limits.
• Understanding the influence of physical parameters is crucial for optimizing LIBS performance.

Purpose of the Study:

• To investigate the impact of water content, droplet displacement, and laser fluence on LIBS signals from single droplets.
• To establish a method for real-time monitoring of droplet evaporation and particle positioning.
• To determine optimal conditions for sensitive and reproducible single-particle elemental analysis.

Main Methods:

• Utilizing electrodynamic trapping to precisely control and position single, additive-free droplets.
• Monitoring droplet evaporation in real-time.
• Adjusting particle position within the laser focal spot with micrometer resolution.
• Analyzing LIBS signals under varying laser fluence and detection delay times.

Main Results:

• LIBS signal intensity increased during the complete evaporation of droplets into residual particles.
• Stable analyte line emission was observed when particles were within the laser focal spot.
• Moving particles 15 μm outside the laser beam path reduced the signal tenfold.
• Optimal detection of most metals was achieved using low laser pulse energy (approx. 6 mJ) and short delay times (approx. 1 μs).

Conclusions:

• Electrodynamic trapping and precise particle positioning significantly enhance LIBS signal stability and sensitivity for single particles.
• Optimized laser parameters (fluence and delay time) are critical for maximizing detection capabilities.
• This approach enables more sensitive and reproducible single-particle elemental analysis, applicable to real-time monitoring of environmental and industrial samples.