Characterization of Nanoparticle Diameter by Asymmetrical Flow Field-Flow Fractionation

This study introduced the general method of asymmetrical flow field-flow fractionation for the particle size measurement of polystyrene latexes. The separation took place under the influence of flow field generated by a cross flow where 0. 1% SDS and 0. 02% NaN3 aqueous solution as carrier phase. Several experimental parameters were optimized including focusing time, cross flow rate, injection mass and channel flow rate, which was important for quantification. It was found that AF4 was particularly useful and simple for the determination of particle size, because the elution profile could be converted to the particle size on the basis of the equation directly. Each sample was injected ten times and the relative standard deviation was less than 1%, which showed that AF4 had high stability. The comparison results of mean diameter determined by AF4 and scanning electron microscope (SEM) showed that the mean diameter of SEM was lower than those obtained from AF4 or provided by manufacturers, therefore AF4 was more accuracy and precise than SEM, which could be developed as an accurate method for size characterization.