A highly efficient capillary electrophoresis-based method for determination of watersoluble CdTe, CdTe/ZnS, and multilayer CdTeSe/CdS/CdZnS/ZnS quantum dots

Various applications and synthesis methods of quantum dots require reliable analytical methods to determine composition, colloidal stability, monodispersity, as well as to identify quantum dots. Therefore, their analysis is of great interest. As a rule, water-dispersible nanoparticles have a surface charge, which makes electrophoretic methods of analysis promising for characterising quantum dots (QDs). Hydrophilic CdTe, CdTe/ZnS, and multilayer CdTeSe/CdS/CdZnS/ZnS QDs were studied using capillary zone electrophoresis (CZE). A method for analyzing and characterizing colloidal QDs by CZE was developed, the influence of factors of the electrophoretic process on the parameters of QDs migration was studied and the conditions for QDs analysis were selected. Optimal conditions have been established for determining quantum dots with a minimum analysis duration and using a borate buffer containing surfactant as a background electrolyte. Since the synthesis of multilayer quantum dots is multi-stage, the developed analysis method can be used for express analysis and characterization of hydrophilic QDs obtained at each synthesis step. In this study, it was shown that by the type of electropherogram and the width of the peak corresponding to QDs, conclusions can be made about the heterogeneity of the synthesized samples in size, the efficiency of each stage of QDs synthesis and purification, and the processes of their degradation during storage.