[Primary study on determination of the size distribution of nanoparticles by capillary zone electrophoresis]

The separation of polystyrene (PS) latex in sizes of 50 nm and 125 nm has been carried out using capillary zone electrophoresis (CZE). The effects of experimental parameters including pH, the concentration of buffer and the voltage, on the separation were investigated. The optimum electrophoretic conditions were as follows: 8.00 mmol/L NaH2PO4 (adjusted to pH 8.00 with ammonia) as buffer, applied voltage of 26 kV and detection wavelength of 214 nm. The relative standard deviation of the migration time and the peak area of PS50 were 0.3% and 4.7%, respectively. The separation was found to be size-dependent. Larger particles exhibited longer migration time. Stable dispersion condition of PS particles in aqueous solution was obtained by adding PS particles into the buffer.