NEW ANALYSIS TECHNIQUE TO ENHANCE ELECTROPHORETIC LIGHT-SCATTERING SPECTRA

A technique that will simplify and enhance the process of obtaining electrophoretic light scattering (ELS) spectra has been developed. In ELS it is the narrow gap electrode configuration that has shown the greatest promise for increased resolution and ease of use. However, the alternating electric field that must be used to avoid electrode polarization effects, etc., introduces harmonic structuring into the Doppler shift spectrum. An analysis technique that uses the phase changes in the signal when the particles reverse direction, to significantly increase the signal-to-noise ratio, and produce the mobility spectrum without harmonics is described. Experimentally this phase-sensitive detection technique gave excellent results when only a few cycles of the electric field were used. This had the advantages of using pulsed electric fields with excellent discrimination against noise and losing little spectral resolution. © 1990.