• Title/Summary/Keyword: Flow field-flow fractionation

Search Result 57, Processing Time 0.023 seconds

Characterization of Asian dust using steric mode of sedimentation field-flow fractionation (Sd/StFFF) (Steric 모드의 침강장-흐름 분획법을 이용한 황사의 특성분석)

  • Eum, Chul Hun;Kim, Bon Kyung;Kang, Dong Young;Lee, Seungho
    • Analytical Science and Technology
    • /
    • v.25 no.6
    • /
    • pp.476-482
    • /
    • 2012

  • Asian dust particles are known to have sizes ranging from a few nanometers up to about a few micrometers. The environmental and health effects depend on the size of the dust particles. The smaller, the farther they are transported, and the deeper they penetrate into the human respiratory system. Sedimentation field-flow fractionation (SdFFF) provides separation of nano to microparticles using a combination of centrifugal force and parabolic laminar flow in a channel. In this study, the steric mode of SdFFF (Sd/StFFF) was tested for size-based separation and characterization of Asian dust particles. Various SdFFF experimental parameters including flow rate, stop-flow time and field strength of the centrifugal field were optimized for the size analysis of Asian dust. The Sd/StFFF calibration curve showed a good linearity with $R^2$ value of 0.9983, and results showed an excellent capability of Sd/StFFF for a size-based separation of micron-sized particles.The optical microscopy (OM) was also used to study the size and the shape of the dust particles. The size distributions of the samples collected during a thick dust period were shifted towards larger sizes than those of the samples collected during thin dust periods. It was also observed that size distribution of the sample collected during dry period shifts further towards larger sizes than that of the samples collected during raining period, suggesting the sizes of the dust particle decrease during raining periods as the components adsorbed on the surface of the dust particles were removed by the rain water. Results show Sd/StFFFis a useful tool for size characterization of environmental particles such as the Asian dust.

  • https://doi.org/10.5806/AST.2012.25.6.476 인용 PDF KSCI

Retention Characteristics of Various Proteins in Flow Field-Flow Fractionation : Effects of pH, Ionic Strength, and Denaturation

  • 송종희;김원숙;박영훈;유의경;이대운
    • Bulletin of the Korean Chemical Society
    • /
    • v.20 no.10
    • /
    • pp.1159-1164
    • /
    • 1999

  • The study investigated the effect of carrier composition (ionic strength and pH) on the retention of various proteins in flow field-flow fractionation (Flow FFF) as well as the conformational change of Bovine Serum Albumin (BSA) with urea concentration, storage time and temperature. The study found that the retention of protein in Flow FFF increased with the ionic strength of the carrier liquid. Most proteins were well solubilized at pH = 7-8. The hydrodynamic diameters obtained from Flow FFF retention data agree well with theoretical values. The retention increased and the peak shape became distorted at extreme pH conditions of the carrier solution. The selected carrier composition for comparison between the literature value of proteins was 0.05 M tris buffer solution with a pH of 8. Storing BSA at 4 ±2℃ over a period of three months resulted in slow dimerization. Also, in case of the storage of BSA at 37 ±5℃ for one week, the retention of both BSA monomer and dimer increased with the urea concentration. Finally, the structural composition of specific enzymes: malonyl-CoA decarboxylase (MCDC) and malonyl-CoA synthesis (MCS) was determined by using Flow FFF at specific carrier solutions. The molecular weight of the natural MCDC was determined to be 208 kDa, which means it is a homotetramer, while that of the MCS was determined to be 47 kDa, which means it is a monomer.

  • https://doi.org/10.5012/bkcs.1999.20.10.1159 인용 PDF

Effect of Carrier Solutions on Particle Retention in Flow Field-Flow Fractionation

  • 문명희
    • Bulletin of the Korean Chemical Society
    • /
    • v.16 no.7
    • /
    • pp.613-619
    • /
    • 1995

  • The influence of carrier solutions on particle retention was studied by varying surfactants and ionic strength in flow field-flow fractionation. Experiments were made with five different submicron polystyrene latex standards at three different types of surfactants and seven different ionic strengths. Departures in particle retention from the general theory were observed. At low ionic strength, it is shown that migrating sample zone is clearly lifted away from the ideal equilibrium height and that the repulsive interaction dominates between the particle and the channel wall. As ionic strength increases up to a certain level, particle retention becomes closer to the general theory. Further increase in ionic strength is shown to prolong the retention. An optimum regime of ionic strength is also suggested with the proper choice of surfactants.

  • https://doi.org/10.5012/bkcs.1995.16.7.613 인용 PDF