TY - JOUR

T1 - Separation and behavior of nonspherical particles in sedimentation/steric field-flow fractionation

AU - Beckett, Ronald

AU - Jiang, Yong

AU - Liu, Guangyue

AU - Moon, Myeong Hee

AU - Giddings, J. Calvin

PY - 1994

Y1 - 1994

N2 - Sedimentation/steric field-flow fractionation (Sd/StFFF) is an elution separation technique capable of measuring the size distribution of 0.3–100µm spherical and near-spherical particles with advantages including high resolution, fast analysis, and the ready collection of narrow size fractions. In this study we investigate the applicability of Sd/StFFF to various nonspherical particles including the doublets of spheres, rod-shaped glass fibers, compressed latex discs, and quartz particles (BCR 67 and 70) with complex mixed shapes. Some fractionation, retention, and selectivity features of these particles are defined and measured in relationship to those of spheres (latex beads), which are better understood. While the relative behavior of these two particle types depends on many factors, especially the distance of the particle from the Sd/StFFF channel wall, in most cases the nonspherical particles are eluted before spheres of equal volume and they often display higher selectivity than spherical particles. However, when retention of nonspherical particles is compared with that for spheres whose diameter is equal to the particle length, elongated particles (doublets and rods) eluted after the sphere while flattened particles (discs) eluted earlier than spheres, an observation that might assist in shape discrimination by Sd/StFFF. Thus, when latex microspheres are used for calibration to obtain size distribution curves, the diameter obtained for any given subpopulation will be less than the length of rods but greater than the diameter of discs. For complex particles such as the quartz particles, the diameter of a particle provided by classical sedimentation using spherical calibration is less than the equivalent spherical diameter of the particle in question whereas Sd/StFFF yields a diameter somewhat greater than the particle length. Thus, these two techniques will yield size distribution curves displaced from one another along the diameter axis. The difference in diameters can be eliminated by using a diameter correction factor of 2.7, which brings the distribution curves for quartz obtained by these two techniques into concurrence.

AB - Sedimentation/steric field-flow fractionation (Sd/StFFF) is an elution separation technique capable of measuring the size distribution of 0.3–100µm spherical and near-spherical particles with advantages including high resolution, fast analysis, and the ready collection of narrow size fractions. In this study we investigate the applicability of Sd/StFFF to various nonspherical particles including the doublets of spheres, rod-shaped glass fibers, compressed latex discs, and quartz particles (BCR 67 and 70) with complex mixed shapes. Some fractionation, retention, and selectivity features of these particles are defined and measured in relationship to those of spheres (latex beads), which are better understood. While the relative behavior of these two particle types depends on many factors, especially the distance of the particle from the Sd/StFFF channel wall, in most cases the nonspherical particles are eluted before spheres of equal volume and they often display higher selectivity than spherical particles. However, when retention of nonspherical particles is compared with that for spheres whose diameter is equal to the particle length, elongated particles (doublets and rods) eluted after the sphere while flattened particles (discs) eluted earlier than spheres, an observation that might assist in shape discrimination by Sd/StFFF. Thus, when latex microspheres are used for calibration to obtain size distribution curves, the diameter obtained for any given subpopulation will be less than the length of rods but greater than the diameter of discs. For complex particles such as the quartz particles, the diameter of a particle provided by classical sedimentation using spherical calibration is less than the equivalent spherical diameter of the particle in question whereas Sd/StFFF yields a diameter somewhat greater than the particle length. Thus, these two techniques will yield size distribution curves displaced from one another along the diameter axis. The difference in diameters can be eliminated by using a diameter correction factor of 2.7, which brings the distribution curves for quartz obtained by these two techniques into concurrence.

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U2 - 10.1080/02726359408906643

DO - 10.1080/02726359408906643

M3 - Article

AN - SCOPUS:0002013721

VL - 12

SP - 89

EP - 113

JO - Particulate Science and Technology

JF - Particulate Science and Technology

SN - 0272-6351

IS - 1

ER -