Shear-driven pumping and Fourier transform detection for on chip circular chromatography applications
Yang, Xin; Jenkins, Gareth; Franzke, Joachim; Manz, Andreas; Yang Xin; Imperial College London, Department of Chemistry; Jenkins Gareth; ISASâ Institute for Analytical Sciences; Franzke Joachim; ISASâ Institute for Analytical Sciences; Manz Andreas; ISASâ Institute for Analytical Sciences
Журнал:
Lab on a Chip
Дата:
2005
Аннотация:
A circular, shear-driven pumping system combined with Fourier Transform detection has been developed for the application of chip based cyclic chromatography. Using this system, it is possible to perform an injection of a sample plug into a circular micro-channel and then drive the sample through the channel, using shear flow induced by a rotation stage. High pumping rates at uniform speeds are attainable with this system with very little heat production. Typical pumping rates of up to 1.423 mm s<sup>â 1</sup> ± 2 µm s<sup>â 1</sup> were used in experiments although much higher rates >14 mm s<sup>â 1</sup> are also possible with this system. Fluorescence detection was used to detect a sample plug of Coumarin dyes, flowing around the channel. A coating of porous polymethacrylate was used to immobilise RP-HPLC beads onto the glass surface and was applied to the glass micro-channel by selective photopolymerisation. This coating acted as a stationary phase and differences in retention time were observed for an injection of Coumarin dyes for different methanolâ water, mobile phase ratios. Full sample retention occurred for 30 : 70 (v/v) methanolâ water whereas no retention occurred for 92 : 8 (v/v) methanolâ water which can be expected for such a reverse phase, open tubular system. Fourier transform detection applied to the fully retained and non-retained cases showed frequency domain data from a single detection point corresponding to that which may be expected from shear flow theory.
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