Mobility measurements by phase analysis

Area of Science:

• Colloid and Surface Science
• Analytical Chemistry
• Physical Chemistry

Background:

• Electrophoretic mobility measurements are crucial for characterizing dispersions.
• Conventional methods face limitations in nonpolar and highly conductive media.
• Phase Analysis Light Scattering (PALS) offers potential for enhanced measurements.

Purpose of the Study:

• To introduce a new instrument for measuring electrophoretic mobilities using PALS.
• To enable measurements in challenging media like nonpolar and highly conductive dispersions.
• To compare the performance of the new PALS instrument with conventional laser Doppler electrophoresis.

Main Methods:

• Development of a new instrument based on Phase Analysis Light Scattering (PALS).
• Implementation of digital signal processing and a reference beam optical configuration.
• Simultaneous measurement capability for both PALS and conventional laser Doppler electrophoresis.

Main Results:

• The new PALS instrument can measure electrophoretic mobilities three orders of magnitude lower than conventional Doppler mode.
• The device incorporates digital signal processing and a reference beam optical system.
• Experimental data show good agreement between PALS and laser Doppler electrophoresis on suitable samples.

Conclusions:

• The developed PALS instrument is effective for measuring electrophoretic mobilities, particularly in nonpolar and highly conductive media.
• The instrument offers significantly improved sensitivity compared to conventional techniques.
• The PALS technique is validated and shown to be in good agreement with established laser Doppler electrophoresis methods.