Effect of asymmetrical flow field-flow fractionation channel geometry on separation efficiency.
The separation efficiencies of three different asymmetrical flow field-flow fractionation (AF4) channel designs were evaluated using polystyrene latex standards. Channel breadth was held constant for one channel (rectangular profile), and was reduced either linearly (trapezoidal profile) or exponentially (exponential profile) along the length for the other two. The effective void volumes of the three channel types were designed to be equivalent. Theoretically, under certain flow conditions, the mean channel flow velocity of the exponential channel could be arranged to remain constant along the channel length, thereby improving separation in AF4. Particle separation obtained with the exponential channel was compared with particle separation obtained with the trapezoidal and rectangular channels. We demonstrated that at a certain flow rate condition (outflow/inflow rate=0.2), the exponential channel design indeed provided better performance with respect to the separation of polystyrene nanoparticles in terms of reducing band broadening. While the trapezoidal channel exhibited a little poorer performance than the exponential, the strongly decreasing mean flow velocity in the rectangular channel resulted in serious band broadening, a delay in retention time, and even failure of larger particles to elute.
Ahn
Ji Yeon
JY
Department of Chemistry, Yonsei University, 262 Seongsanro, Seodaemun-gu, Seoul 120-749, South Korea.
Kim
Ki Hun
KH
Lee
Ju Yong
JY
Williams
P Stephen
PS
Moon
Myeong Hee
MH
D000465:Algorithms; D031521:Fractionation, Field Flow / Q000295:instrumentation / Q000379:methods; D016015:Logistic Models; D008956:Models, Chemical; D011137:Polystyrenes / Q000737:chemistry
D011137:Polystyrenes; C024075:styrofoam