Effect of temperature on particle separation in hollow fiber flow field-flow fractionation

Abstract

Hollow fiber flow field-flow fractionation HF-FlFFF has been tested Ž . by varying the temperature 21᎐73ЊC to increase separation speed with reduced lift forces. It has been experimentally shown that the separation time of 0.050᎐0.426-m polystyrene latex standards can be reduced approximately by half, at 59ЊC, compared to the separation at room temperature. In addition, the resolution for the separation of large diameter particles, which are often influenced by the lift forces, is greatly improved. It also has been found that the steric Ž inversion diameter can be possibly shifted to a larger diameter up to about 0.800 . m at 73ЊC. The steric retention of particles is observed to increase with temperature due to the decrease in hydrodynamic lift forces that is known to decrease with the viscosity of the carrier liquid.

High performance, disposable hollow fiber flow field-flow fractionation for bacteria and cells. First application to deactivatedVibrio cholerae

“…However, with respect to asymmetrical FlFFF with rectangular channel design and transparent depletion wall in which a dye is used to find the focusing position [3], in HF FlFFF we have found no means to visualize focalization. The best focalization point was thus found by first pre-setting, via the relevant metering valves, the flow ratio inside the channel, from the inlet to the outlet and from the outlet to the inlet, at about 1:9, as reported in literature [14,15]. Subsequently, the correct focusing position was tested by the evaluation of the highest retention and resolution between two PS standards (see Section 2: Materials and Methods).…”

“…The HF channel was built up as previously described [14,15], except that the 1/899 tee union inserted for the radial flow rate outlet was here in nylon. The hollow fiber used was made of polysulfone, having a molecular weight cutoff of 30,000 Da, supplied by SK Chemicals (Seoul, Korea).…”

“…These improvements have been achieved through optimization of the HF FlFFF channel design and relevant instrumental system. With these HF FlFFF systems an increase in separation speed and resolution of nano-sized particles has been accomplished and, by increasing the working temperature, with extension to a size range as high as 1 lm [15]. Even though HF FlFFF can be considered as still being in its early development stage, its potential for effecting particle separation at low cost and low sample loads has already been demonstrated.…”

“…For this work the HF FlFFF system configuration already reported in early work [14,15] was modified as shown in Figure 1) and by adjusting valve 2. After sample injection, the focusing/relaxation process was carried out at the same V pump value, by further splitting the V in flow into two parts (delivered to both inlet and outlet of the HF channel) via a 3-way, tee valve (Hamilton) (valve 5, Figure 1) and a 2-way, "L" valve (Upchurch, Oak Harbor, WA) (valve 9, Figure 1).…”

“…The focusing/relaxation of the injected sample components is usually accomplished inside the channel at position 0.1 L from the inlet (where L is the geometrical length of the fiber) [14,15]. However, with respect to asymmetrical FlFFF with rectangular channel design and transparent depletion wall in which a dye is used to find the focusing position [3], in HF FlFFF we have found no means to visualize focalization.…”