A practical comparison of photon correlation and cross-correlation spectroscopy in nanoparticle and microparticle size evaluation

Monodisperse standard polystyrene particles were used to determine the differences between two methods for analyzing particle size based on dynamic light scattering—namely photon correlation spectroscopy (PCS) and photon cross-correlation spectroscopy (PCCS). We demonstrate that the cross-correlation technique achieves results more in line with real particle properties not only with respect to monodisperse systems, but also with respect to polydisperse standard polystyrene particle systems. In addition, suspensions of superparamagnetic iron oxide nanoparticles or PLGA (Poly(Lactide-co-Glycolide)) particles were studied by both PCS and PCCS in order to compare the measurements of non-standardized particles. Both methods were suitable for particle size distribution analysis with respect to the studied particle systems, but photon cross-correlation spectroscopy yielded more precise results and was able to distinguish particles with a diameter ratio of 4, whereas PCS showed a monomodal particle size distribution when measuring particles with a diameter ratio of 5. Measurements of non-standard samples confirmed previous findings that PCCS is more suitable for measurements of multi disperse systems.