Pump- and Valve-Free Flow Injection Capillary Liquid Electrode Discharge Optical Emission Spectrometry Coupled to a...

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Plasma Physics

Background:

• Traditional methods for metallic species determination often require large sample volumes.
• Microplasma optical emission spectrometry offers a sensitive analytical technique.
• Miniaturization and low power consumption are key goals for developing portable analytical instruments.

Purpose of the Study:

• To develop a miniature, low-power capillary liquid electrode microplasma optical emission spectrometer.
• To enable rapid, automated determination of metallic species in aqueous solutions with minimal sample volume.
• To assess the performance and applicability of the developed system for trace metal analysis.

Main Methods:

• A miniature (2.5 cm × 2.0 cm × 1.0 cm) capillary liquid electrode microplasma optical emission spectrometer with <10 W power consumption was designed.
• Automated sample introduction was achieved using capillary attraction and microplasma-induced vaporization, eliminating the need for pumps.
• A droplet array sampling platform facilitated flow injection analysis without valves, achieving a throughput of 90 samples/hour.
• Sample volume was controlled to the nanoliter level via sampling time.

Main Results:

• Detection limits of 30 μg L⁻¹ for Cd and 75 μg L⁻¹ for Hg were achieved with a 10-second sampling time (600 nL).
• Sample consumption was reduced over 100-fold compared to conventional methods.
• The system demonstrated suitability for analyzing elements like Cd, Hg, Li, Na, and K, especially when sample volumes are limited.
• Successful determination of Cd and Hg in blood, water samples, and certified reference materials was achieved.

Conclusions:

• The developed miniature microplasma optical emission spectrometer provides a rapid and sensitive method for metallic species analysis.
• The system's low power consumption, automated sample introduction, and minimal sample volume requirements make it highly suitable for field applications and precious sample analysis.
• This technique offers a significant advancement for trace element analysis in diverse matrices, including biological and environmental samples.