University of Michigan

Omniscent Inc.

Yutao Qin

Yogesh B Gianchandani

Seungdo An

Declan Winship

Weilin Liao

Hsueh-Tsung Lu

An improved gas chromatography system is presented. The system comprises: an enclosure having an inlet and an outlet, such that the ventilation flow is from the inlet to the outlet; a chamber disposed in the enclosure; a monolithic gas analyzer disposed in the chamber and a temperature control unit disposed in physical contact with the chamber. The monolithic gas analyzer operates to separate and detect molecules from a gas; whereas, the temperature control unit is configured to control temperature inside the chamber.

Monolithic microfabricated gas analyzer and enclosure

A progressive cellular architectures has been presented for vapor-phase chemical analyzers. The progressive cellular architecture consists of a series of heterogeneous micro-gas chromatography cells. Each individual cell targets vapor species within a specific volatility range by using a unique combination of a preconcentrator and a separation column. The cells are connected progressively in series to cover a broad range of volatile analyte chemical vapors. Valves may inadvertently absorb or adsorb and subsequently release target chemical analyte molecules, thereby interfering with quantitative analysis. Therefore, the inlet to the cells is configured without a valve.

Progressive cellular architecture for microfabricated gas chromatograph

In order to achieve a system capable of analyzing a wide range of compounds while saving time and energy consumption, a progressive cellular architecture is presented for vapor collection and gas chromatographic separation. Each cell includes a preconcentrator and separation column that are adapted for collecting and separating compounds only within a specific volatility range. A wide volatility range can therefore be covered by the use of multiple cells that are cascaded in the appropriate order. The separation columns within each cell are short enough to reduce the heating and pumping requirements. The gas flow for vapor collection and separation is provided by low-power gas micropumps that use ambient air. The system is also configurable to incorporate capabilities of detecting and reducing vapor overload. The progressive cellular architecture directly address the compromise between low power and broad chemical analyses.

A microfabricated gas flow structure includes an array of vertical gas flow channels in a side-by-side parallel flow arrangement. Adjacent gas flow channels are separated by a thin wall having a thickness which can be an order of magnitude or more less than the channel width, offering exceptionally high area efficiency for the array. Channel walls can be formed from a dielectric material to provide the walls with sufficient integrity at nanoscale thicknesses and to provide thermal insulative properties in the lateral direction, thereby controlling power losses when the gas flow structure is employed as a Knudsen pump. The gas flow structure can be microfabricated as a monolithic structure from an SOI wafer, with the gas flow channels formed in the device layer and the heat sink formed from the handle layer.

Microfabricated gas flow structure

A method is presented for fabricating a fluidic system for a gas chromatograph. The method includes: microfabricating a portion of a fluidic system of a gas chromatograph on a substrate using a first mask; microfabricating a portion of the fluidic system of the gas chromatograph using a second mask; and microfabricating a portion of the fluidic system of the gas chromatograph using a third mask, such that the first mask, the second mask and the third mask are different from each other and the microfabricating of the fluidic system of the gas chromatograph is completed using only the first, second and third masks. A gas chromatograph wherein a microfabricated Knudsen pump is arranged to operate in a first direction to draw carrier gas into a preconcentrator and in a second direction to draw gas out of the preconcentrator.

Growing community of inventors

Ann Arbor, MI, United States of America

Yutao Qin