A method has been developed to increase the sensitivity of phase Doppler interferometry-based particle sizing systems to small particles in the presence of a spray containing large and small droplets; an important consideration when using seed particles to track the gas-phase velocity in multi-phase flows. The method, applicable to PDPA systems configured to operate in first and higher order refraction mode, involves doping the sprayed liquid with a dye that is strongly absorbing at the incident laser wavelengths. This results in greatly diminished scattered intensity from larger droplets, thus allowing the photomultiplier gain to be set to a level sufficient to easily detect small particles without saturation. Tests conducted indicate that, at a collection angle of 30 degrees and droplet absorptivity of gamma = 0.014/mu m, the PDPA can accurately size absorbing droplets up to approximately 200 mu m. This upper limit can be extended by changing cellection angle. Tests performed with an actual spray demonstrated that the method allowed detection of 1 mu m to 235 mu m droplets; more than four times the instrument＇s usual range of 50 : 1. A data correction scheme to determine the effective probe volume radius for each particle size class has been developed for absorbing particles, as standard correction schemes derived for non-absorbing droplets excessively weigh distributions toward smaller particles.