Optical chromatography: Size determination by eluting particles

A new method for the determination of particle size was developed using optical chromatography. After separating polystyrene particles, the laser power was gradually reduced, permitting the elution of small to large particles. Particle size was calculated from the laser power when the particle was eluted with a medium flow. This approach is more accurate than the technique previously reported because there is no need to determine the position of the beam waist. Advantages of the new approach are discussed theoretically and experimentally. The precision in size determination was improved by a factor of 3.3, i.e. the standard deviation in the measurement was reduced from 10 to 3% for 1 μm beads by replacing optical chromatography with the present method.