37 results about "Micro gas chromatography" patented technology

A microelectromechanical heating apparatus and fluid preconcentrator device utilizing same wherein heating elements of the apparatus are sized and spaced to substantially uniformly heat a heating chamber within a heater of the apparatus. Tall, thermally-isolated heating elements are fabricated in Si using high aspect ratio etching technology. These tall heating elements have large surface area to provide large adsorbent capacity needed for high efficiency preconcentrators in a micro gas chromatography system (μGC). The tall heating elements are surrounded by air gaps to provide good thermal isolation, which is important for a low power preconcentrator in the μGC system.

This invention relates to the field of miniaturing gas chromatograph instruments using microfabrication technologies. In particular, the invention provides a gas chromatograph column, which column comprises at least two lid layers and a channel layer, wherein each of said layers comprises a compact material suitable for gas chromatograph, said channel layer comprises microfabricated channels on both sides, said microfabricated channels and a side of said lid layers form at least two capillaries, said at least two capillaries are connected to each other through a hole in said channel layer to form an integrated capillary, said integrated capillary is connected to outside atmosphere on both ends via holes on two outmost lid layers to serve as an inlet and an outlet.

The invention discloses an arrayed micro gas chromatographic column chip with a super-large contact area. The chip comprises a silicon substrate (5), channels (2) and arrayed vertical pillars (3) processed on the silicon substrate (5), the arrayed vertical pillars (3) are distributed in the channels (2), a layer of porous silicon (7) grows on the surface of each of the channels (2) and the arrayed vertical pillars (3) through an electrochemical corrosion method after the arrayed vertical pillars (3) and the channels (2) are processed, and the surface of the porous silicon (7) is fixed with a stationary phase. The chip comprises a sealing layer (6) sealing the channels (2) on the silicon substrate (5) in a bonding manner. The porous silicon of the chip has a loose and porous structure, so the surface area of the chip increases thousands of times; and the surface of the porous silicon is fixed with the stationary phase, so the bonding area of the stationary phase in the chromatographic column can be greatly increased, and is 5-10 times higher than that the bonding area of the stationary phase in a chromatographic column having an empty channel structure. The change of the speed and the pressure of a gas flow in channels having the above structure is much smaller than the change of the speed and the pressure of a gas flow in chromatographic columns having the empty channel structure, so the mixed gas separation capability is greatly improved.

The present invention provides a detector and method for detecting substances in complex mixtures. The detector includes a microfabricated preconcentrator, a separation column with an on-chip thermal conductivity detector, a controller for controlling flow and thermal management and a user interface. The thermal conductivity detector includes a first resistor located at an inlet of the separation column and a second resistor located at an outlet of the separation column.

The invention discloses a micro gas chromatographic column chip. The chip comprises a silicon substrate, wherein parallel channels which are sequentially communicated are formed in the silicon substrate, regularly arranged silicon substrate cylinders are arranged in the channels, the height of the cylinders is consistent with the depth of the channels, a gas inlet and a gas outlet are also formed in the silicon substrate, a sealing layer is arranged on the silicon substrate and sealed with the silicon substrate through a sealant, so that the gas inlet, the channels and the gas outlet form a closed gas flow path, and a double-layer stationary phase structure is arranged on the channels and cylinder surfaces in the gas flow path. According to the chip, the contact area of stationary phases can be increased by the aid of cylinder structures, meanwhile, the double-layer stationary phase structure is adopted, the separating capacity of the chromatographic column chip can be enhanced, and the separation variety of the chip for samples can be increased.

The invention discloses a micro gas chromatographic column with high depth-to-width ratio and a wet corrosion manufacturing method thereof. In the micro gas chromatographic column, a broken line chromatographic groove is formed on a (110) single crystal silicon substrate, the included angle of the long and short edges of the broken line is 70.53 degrees, and the long and short edges are along the (110) and (112) crystal directions of the substrate respectively. Vertical deep grooves with high depth-to-width ratio are formed by adopting an anisotropic wet corrosion method in the broken line chromatographic column and bonded by silicon glass bonds, so that the whole broken line groove has high depth-to-width ratio; and long enough column length is realized in a small area. On the characteristic dimensions of depth-to-width ratio, column length, area and the like, the broken line deep groove is equivalent to a vertical deep groove processed by deep reactive ion etching (DRIE); and the adopted wet corrosion processing method is simple and feasible, expensive DRIE etching equipment is not needed, and the processing cost is greatly reduced.

The invention discloses a micro gas-phase chromatographic column with an ultrahigh depth-to-width ratio and a micro-electromechanical system (MEMS) machining method thereof. The micro gas-phase chromatographic column comprises a bottom layer, a plurality of intermediate layers and a top layer which are formed by a plurality of silicon layers and a plurality of glass layers, wherein a hollow vertical channel with the same pattern is formed in each intermediate layer by dry etching technology; half-etched vertical channels are formed in the bottom layer and the top layer; the bottom layer, the intermediate layers and the top layer are combined by anodic bonding according to a silicon-glass alternative sequence; and the vertical channels in the layers of materials are strictly aligned. The chromatographic column and the method have the advantage that: the deep channels of the layers are laminated layer after layer along the vertical direction by bonding technology; and thus, the depth of the channel is not limited the depth-to-width ratio required by dry etching, and the vertical deep channel with the ultrahigh depth-to-width ratio of over 1mm can be realized so as to greatly improve the performance of a chromatogram.

The invention discloses a preparation method of a micro gas chromatographic column chip with a high aspect ratio. The method comprises the steps of manufacturing a metal pattern plate, preprocessing a silicon wafer, performing a uniform adhesive photolithography technology, and performing developing; then, sputtering a metal aluminum layer to be adopted as a masking layer, performing ultrasonic stripping, enabling a channel to be etched to be exposed, performing deep dry etching, and adjusting perpendicular etching and sedimentation protection parameters; performing anodic bonding on two substrates with identical etching graphs, sputtering a thin film heater and a temperature measuring resistor on the two faces of the substrates obtained after bonding is completed; forming a PDMS thin film inside a micro chromatographic column by adopting a static coating method. According to the obtained micro gas chromatographic column, the side wall is steep, the aspect ratio is large, the aspect ratio of the micro gas chromatographic column is increased by one time on the basis of original etching, the preparation method is simple and reliable, and the obtained micro gas chromatographic column chip is high in sensitivity and resolution ratio.

The present invention provides a silicon-based micro-gas chromatography column with high separation efficiency, and a preparation method thereof. The preparation method comprises: 1) producing a micro-ditch channel and a micro-fluidic port on a silicon substrate; 2) producing a mask layer to protect the bonding surface on the silicon substrate; 3) constructing nanometer mesoporous silica in the micro-ditch channel; 4) bonding a packaging cover plate onto the bonding surface of the silicon substrate; and 5) forming a corresponding modification material on the surface of the nanometer mesoporoussilica based on the component to be separated. According to the present invention, due to large specific surface area, large pore volume, good thermal stability and good mechanical strength of the nanometer mesoporous silica, the nanometer mesoporous silica is constructed in the silicon-based micro-gas chromatography column so as to substantially improve the separation efficiency of the chromatography column; and the surface of the nanometer mesoporous silica has the high-density silanol (Si-OH), such that the single molecule layers having different separation functions can be further constructed on the surface according different separated objected so as to achieve the desired separation effect.

A wavy micro gas chromatography column includes a silicon substrate and a bonded glass cover. A micro channel having a rectangular cross section is etched on the silicon substrate and coated with a stationary phase film. A projection figure of the micro channel on the silicon substrate includes multiple regular wavy curves. Each wavy curve is formed through alternately connecting first upper arcs with first lower arcs. Because the groove has a curving structure, the carrier gas velocity is decreased as the increase of the arc angle, resulting in an improvement of the flow uniformity at the zones between two adjacent bends but also an enlarging nonsymmetric distribution at the bends. Thus, an optimal curving structure can make the overall flow more even, and in turn achieve a better separation performance compared to the straight channel columns. Meanwhile, a wavy channel realizes a longer column length on a given area.

The invention provides a minisized gas-chromatographic-column chip and a preparation method thereof. The chip comprises at least two mutually-independent chromatographic channels, which are filled with stationary phases in different phase states; at least one connecting channel, which is connected with and located between two adjacent chromatographic channels and used for realizing communication between two adjacent chromatographic channels; and at least one solenoid valve, which is arranged in one connecting channel and used for opening or closing the connecting channel to enable gas to flowthrough the two chromatographic channels communicating with each other via the connecting channel when the connecting channel is opened. According to a scheme of the invention, usage of a single chromatographic channel or combined usage of a plurality of chromatographic channels can be realized through opening or closing of the solenoid valves, so active selection can be performed according to ambient gas; i.e., the chromatographic channels can be filled with a plurality of stationary phases; and thus, the variety of separated gas is greatly increased, and combined usage of a plurality of chromatographic columns is not needed for mixed gas with complicated background, which enables the size of a system to be greatly reduced.

The invention provides a silicon-based micro gas chromatography column and a preparation method thereof. A layer of fine silicon nanowire forest is designed and prepared on the inner surface of a microchannel of the silicon micro chromatography column, and the nanowire diameter is generally distributed between several nanometers to tens of nanometers. The fine silicon nanowire forest greatly increases the surface area of the silicon micro chromatography column, and the column capacity, the resolution and the column efficiency of the silicon micro chromatography column are thus effectively improved.

The invention discloses a miniature gas chromatograph for atmospheric pollution detection and relates to the technical field of meteorological chromatographs. The miniature gas chromatograph comprises a protective shell, wherein a roller is movably connected to the bottom of one side of the protective shell, a telescopic rod is movably connected to one side of the interior of the protective shell, and a rotating fluted disc is rotatably connected to the center of the top of the protective shell; guide rods are fixedly connected to two sides of an inner wall of the top of the protective shell, one end of each guide rod is sleeved with a rack, the other end of each guide rod is sleeved with a first compression spring, the racks are movably connected with the protective shell through the first compression springs, and one end of each rack is fixedly connected with a pull rod; and a second compression spring is fixedly connected into one end of the rack. According to the device, the door plate structure is arranged on one side of the protective shell, when the device is not used, the door plate can be closed, safety of the device is improved, the service life is prolonged, and when the device is used, the door plate can be opened to work normally.

The invention discloses a miniature gas chromatographic column capable of using air as carrier gas and a manufacturing method thereof. The manufacturing method comprises the following steps of photoetching and stripping on a silicon wafer to form an aluminum mask layer, forming a chromatographic column micro-channel with a micro-upright column array through etching, soaking the silicon wafer in an acid solution, removing the mask and bonding the silicon wafer with borosilicate glass, sputtering titanium and platinum on the back surface of the silicon wafer as a temperature measuring resistor, a heating wire and an electrode, sputtering gold as an electrode pin, enabling the capillary tube to be connected with two ports of the micro gas chromatographic column, and constructing mesoporous silica microspheres in a chromatographic column micro-channel, and coating an ionic liquid stationary phase in a static coating mode. The mesoporous structure in the chromatographic column greatly increases the coating area of a stationary phase, improves the separation capacity within the limited chromatographic column length, has good tolerance to oxygen, ensures high reliability, high stability and high column efficiency of the micro-chromatographic column in a high-temperature aerobic environment, can directly use air as carrier gas, and an excellent micro-chromatographic column is provided for a VOCs detection system.

The invention discloses a miniature gas chromatographic column box which comprises a miniature chromatographic column box body, a heating unit, a heat dissipation unit and a processing control unit; the miniature chromatographic column box body comprises a first metal plate with a spiral groove cavity and a second metal plate; the first metal plate and the second metal plate can be fastened, matched and sealed through fixing holes formed in the four corners of the first metal plate and the second metal plate respectively. According to the miniature gas chromatographic column box disclosed by the invention, the chromatographic column box is more miniaturized, the temperature of the chromatographic column adopts a contact type heat conduction mode, the temperature control of the chromatographic column is more direct, the temperature control precision is high, and the reproducibility is better; the miniature gas chromatographic column box can promote the miniaturization development of a chromatographic instrument, so that the portability of the gas chromatographic instrument is promoted, and the application prospect of the gas chromatographic instrument can be greatly expanded.

The invention provides a cancer detection method and a cancer detection system based on micro gas chromatography, which can realize non-interference and high-sensitivity detection of all gas molecules in breathing gas aiming at the demand of diagnosing major diseases by the breathing gas, and high detection precision. A micro gas chromatography and a high-sensitivity broad-spectrum sensor are integrated, the diagnostic instrument is a high-integration portable diagnostic instrument for detecting diseases through breathing gas, only breathing gas of a patient is needed, and non-invasive detection is achieved; according to the method, the sample injection valve is combined with the two chromatographic columns, the capacity of treating complex samples can be improved (the separable components are more in variety and wider in range), the micro chromatographic column method is adopted for developing cancer detection, and the method can accurately detect the accurate content of each component of the respiratory gas, the technical bottleneck of weak anti-interference capability of the sensor is solved, the portability of the detector can be improved, and the field detection requirement is met.

The invention provides a multi-channel miniature gas chromatographic column chip and a preparation method. The multi-channel miniature gas chromatographic column chip comprises at least two mutually independent and parallel chromatographic channels andgas branching channels, wherein the chromatographic channels are filled with different stationary phases; and the gas branching channels are arranged between two adjacent chromatographic channels, are communicated with the other sides of the chromatographic channels, and are used for dividing the gas to be separated into multiple paths and respectively introducing the multiple paths into each chromatographic channel. The miniature gas chromatographic column chip which is small in size, low in power consumption and multi-channel and designed according to the scheme of the invention can realize rapid and efficient separation of environmental pollution gas.

The invention provides a chromatographic material and a preparation method thereof, a micro chromatographic column and a coating method thereof, and a micro gas chromatograph. The preparation method of the chromatographic material comprises the following steps: adding a layer of stationary phase of a metal organic framework material on the surface of the magnetic particles to realize surface modification, and then cleaning and separating to take out the magnetic particles; and repeating the steps for N times, wherein N is a positive integer. According to the technical scheme of the invention, firstly, the surface of the chromatographic material is coated with a plurality of layers of metal organic framework materials as a stationary phase, so that the chromatographic material has a deeper internal structure and a larger specific surface area, and the chromatographic separation performance can be obviously improved; and secondly, as the carrier of the chromatographic material adopts the magnetic particles, the external magnetic force can be utilized to assist the separation operation and be fixed in the chromatographic column, and the method has the advantages of simplicity, convenience and feasibility.