The device has 56 separation channels with a length of 4cm, a width of 50-150µm, and a depth of 5-18µm. The channels are packed with vertical micro-cylinders. These pillars are 1-5µm thick, and are separated by gaps of 1-0.1µm. Within one channel, all pillars have an identical shape, size, and distance. The chromatograph was implemented on a 200mm Si wafer.
First, a Si oxide layer was deposited on the wafer, on which the submicron structures of the chromatograph were patterned and etched. Next, with the Si oxide layer as hard mask, the separation channels and the pillars were etched with deep reactive ion etching (DRIE). The separation channels were then connected via wider interconnecting supply channels. A 200mm glass wafer was bonded to the Si wafer, serving as a roof to close off the open separation channels. And last, access holes were etched through the back of the Si wafer.
A comparison with commercial chromatographs with macroscopic tubes shows that the micro-chromatograph is 5 to 10 times as fast, and has a better separation capacity. Also, unlike with macro-chromatographs, the separation does not degrade with higher velocities of molecule transport. The performance of the chromatograph was tested by injecting a fluid with tracer molecules in the chromatograph and following the velocity and width of the resulting tracer band.
Liquid phase chromatography is a powerful technique to separate and identify molecules. It is used, for example, in biochemistry labs to separate proteins. The molecules, suspended in a liquid, are separated by forcing them through macroscopic columns filled with micron-sized, randomly packed spherical particles. This sub-micro chromatograph validates fluid dynamic computations that predict that injecting molecules though a submicron maze of perfectly ordered structures will considerably increase the separation speed of liquid phase chromatography.
Katrien Marent | alfa
Significantly more productivity in USP lasers
06.12.2016 | Fraunhofer-Institut für Lasertechnik ILT
Shape matters when light meets atom
05.12.2016 | Centre for Quantum Technologies at the National University of Singapore
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
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Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
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