Standardless method for quantitative particle-size distribution studies bygravitational field-flow fractionation. Application to silica particles

Gravitational field-flow fractionation is a separative analytical technique which has already proved suitable for quantitative particle-size distribut ion analysis. One of the most attractive aspects of the technique is that i t can allow for direct conversion of fractograms into size distributions of the samples, although retention exhibits substantial dependence on flow ra te, compared to other field-flow fractionation methods. It is shown here that conversion of fractograms into quantitative, size-dis tribution profiles of micron-sized silica particles is possible through gra vitational field-flow fractionation in standardless mode. Standardless mean s that the conversion of fractograms is performed by single-run analysis be cause all the parameters necessary for the calculations can be obtained, fr om sample specifications and previous instrumental calibration, by means of semiempirical models.