A chip-based supersonic microfluidic nebulizer for efficient sample introduction into inductively coupled plasma -...

Area of Science:

• Analytical Chemistry
• Microfluidics
• Mass Spectrometry

Background:

• Increasing use of microfluidic chips for biological sample handling necessitates advanced analytical techniques.
• Conventional pneumatic micro-flow nebulizers for coupling microfluidics to ICP-MS suffer from dead volume and liquid suction issues.
• There is a need for improved nebulization methods for chip-based ICP-MS to enhance metal determination capabilities.

Purpose of the Study:

• To demonstrate the potential of a chip-based supersonic microfluidic nebulizer (chip-μf-Neb) for advancing metal determination in chip-based ICP-MS.
• To showcase the convenient coupling of the chip-μf-Neb to ICP-MS using a spray chamber with laminar flow makeup gas.
• To evaluate the system's performance at low liquid flow rates for sensitive metal quantitation.

Main Methods:

• Development and integration of a chip-based supersonic microfluidic nebulizer (chip-μf-Neb) with ICP-MS.
• Optimization of nebulization and makeup gas flow rates for maximum sensitivity and minimal oxide formation.
• Evaluation of the system's performance using indium (In) for sensitivity, silver (Ag) nanoparticles for transport efficiency, and single-cell analysis for selenium (Se) and arsenic (As).

Main Results:

• Achieved a maximum indium sensitivity of 40000 cps/(μg L⁻¹) at a flow rate of 10 μL min⁻¹.
• Demonstrated a transport efficiency of 46% for silver nanoparticles.
• Successfully detected selenium and arsenic in individual Chlamydomonas reinhardtii cells.

Conclusions:

• The chip-based supersonic microfluidic nebulizer (chip-μf-Neb) offers efficient operation at low liquid flow rates.
• The absence of self-aspiration makes this nebulizer a promising tool for chip-based ICP-MS.
• This technology advances metal quantitation by effectively combining microfluidics with ICP-MS.