Flowing liquid-sheet jet for cavity ring-down absorption measurements

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Physical Chemistry

Background:

• Cavity ring-down spectroscopy (CRDS) is a sensitive technique for measuring absorption.
• Traditional CRDS often requires stable sample environments.
• Developing new sample delivery methods is crucial for expanding CRDS applications.

Purpose of the Study:

• To introduce and validate a flowing liquid-sheet jet as a stable sample interface for CRDS.
• To assess the performance of this technique for absorption measurements.
• To explore its potential in analytical and spectroscopic studies.

Main Methods:

• A mechanical gear pump delivered solvent through a circular orifice, creating a liquid jet.
• The jet impacted a surface, forming a stable liquid sheet positioned at the Brewster angle.
• A pulsed laser was used within a linear ring-down cavity for absorption measurements.

Main Results:

• The path length of the ethylene glycol sheet-jet was measured at 23.2 ± 0.6 μm.
• Malachite Green dye demonstrated a linear dynamic range of 12.6 dB (73.9 nM to 1.34 μM).
• The limit of detection was determined to be 71 nM (αLOD = 0.0162 cm⁻¹).

Conclusions:

• The liquid-sheet jet is a stable and effective sample interface for CRDS.
• This technique shows significant promise for high-sensitivity analytical and spectroscopic measurements.
• Potential applications include studies of gas-liquid interfaces and other demanding analyses.