LISSAJOUS-LIKE PATTERNS IN SCATTER PLOTS OF CALIBRATION BEADS

Flow cytometric measurements of light scattering of polystyrene calibr ation beads revealed remarkable Lissajous-like loops in two-parameter scatter plots. The existence of such loops is shown to be in qualitati ve agreement with Lorenz-Mie scattering theory of homogeneous spheres. The occurrence of these patterns reflects the extreme particle size d ependency of perpendicular light scattering of homogeneous spheres. Th ese effects may give an explanation for the frequently observed phenom enon that polystyrene spheres reveal a relatively large CV in the perp endicular light scattering signals, whereas the CV of the forward ligh t scattering signal is small. We conclude that one should be careful t o optimize the perpendicular light scattering channel by minimizing th e CV, because there is no linear relationship between instrument align ment quality and the CV of the perpendicular light scattering signals of calibration beads. (C) 1994 Wiley-Liss, Inc.