Gas chromatography kinetic-based spectral bandwidth compression method, compression device, method of operation and applications thereof

Abstract

The application provides a spectrum band width compression method based on gas chromatography kinetics, a compression device, an operation method and application thereof. The core principle of the application is to realize spectrum band width compression by using the difference between the movement speed of the gas spectrum band in high and low temperature zones and the spectrum band width expansion speed, and to keep the separation degree basically unchanged by using the mechanical movement of the capillary chromatographic column from the high temperature zone to the low temperature zone, space for time. The device comprises a spectrum band compression assembly, a transmission line, a first storage box and a third storage box, the spectrum band compression assembly comprises a second storage box, a first transmission device, a second transmission device and a temperature control system. The application can compress the peak width of the target component by 10-20 times, the detection sensitivity is improved by 10-20 times, and the separation degree of the target component is basically unchanged.

Description

Technical Field

[0001] This invention relates to the field of gas chromatography analysis technology, and more particularly to a band width compression method based on gas chromatography kinetics, a compression device and its operation method, and its application in improving gas chromatography sensitivity. Background Technology

[0002] Improving sensitivity is a constant goal pursued by analysts. There are various ways to improve sensitivity, the most common of which are to increase the sensitivity of the detector itself and to increase the concentration and enrichment factor of the sample.

[0003] Improving detector sensitivity requires instrument upgrades, which are costly and have sensitivity limitations. The concentration factor is also limited by the sample quantity and matrix (at high concentrations, the sample precipitates from the solution). This invention provides a new technique for improving sensitivity. This method is fully compatible with other methods, and regardless of advancements in existing technology, this invention can further improve sensitivity by 10-20 times. Summary of the Invention

[0004] This invention provides a band width compression method based on gas chromatography kinetics, a compression device, its operation method, and its application. This invention proposes a new method suitable for capillary gas chromatography analysis, in addition to existing conventional methods for improving sensitivity: a band width compression method based on chromatographic kinetics, and constructs a corresponding device. According to the chromatographic theory formula (1), the plate height, which is positively correlated with the band width, is affected by the following factors: A is the eddy diffusion term, B is the longitudinal diffusion term, and C is the mass transfer resistance term. For capillary gas chromatography, B is the dominant influencing factor. The broadening of the gas chromatographic band mainly occurs in the longitudinal diffusion near the effluent temperature. Introducing the target band that has been separated into a low-temperature region (a temperature difference of more than 100°C from the effluent temperature) allows for band width compression due to the simultaneous rapid decrease in band movement speed and longitudinal diffusion. During the compression process, the compression column is continuously and uniformly transported from the high-temperature region to the low-temperature region at a speed of 10-20 cm / min, trading space for time, which ensures that the resolution of adjacent chromatographic peaks remains essentially unchanged. Compression of the band width of mass detectors (FID, ECD) results in a proportional increase in mass concentration (mass / time), thus the sensitivity will be improved by 10-20 times after band compression.

[0005] The technical means employed in this invention are as follows:

[0006] A band width compression method based on gas chromatography kinetics is proposed. This method utilizes the difference in the speed of gas chromatography band movement and the speed of band broadening in high and low temperature regions to achieve band width compression. It also utilizes the mechanical movement of the capillary column from the high temperature region to the low temperature region to exchange space for time and maintain the resolution essentially unchanged.

[0007] Furthermore, the capillary column is moved from the high-temperature zone of the gas chromatograph oven to the low-temperature zone of the compression assembly via a mechanical transmission device. Taking advantage of the significant difference in retention and band movement speed between the components at the normal separation column temperature zone and the low-temperature zone of the compression assembly, the band width is compressed by rapidly reducing the band movement speed and longitudinal diffusion simultaneously.

[0008] This invention also provides a universal band width compression device based on gas chromatography kinetics, constructed using the aforementioned band width compression method based on chromatographic kinetics. It includes: a band compression component, a transmission line, and a first and a third storage box disposed in the column oven of a gas chromatograph. The transmission line connects the band compression component to the gas chromatograph. The band compression component includes a second storage box, a first transmission device, a second transmission device, and a temperature control system. The first, second, and third storage boxes are used to store the compressed column, and the third storage box is connected to a detector in the column oven.

[0009] The compression column is used to compress the target component's spectral width. It is initially stored in the first storage box. The starting end of the compression column is connected to the analytical column in the column oven. The analytical column is used for gas chromatography separation of the target component. The carrier gas is delivered to the compression column through the analytical column.

[0010] The first transmission device is used to transmit the compressed column in the first storage box through the transmission line to the second storage box, and the second transmission device is used to transmit the compressed column in the second storage box through the transmission line to the third storage box. The compressed column transmitted to the third storage box is connected to the detector.

[0011] Furthermore, the first, second, and third storage boxes are all flat metal boxes, and the capillary chromatographic column is introduced into and drawn out of the flat metal box using a graphite tube.

[0012] When the transmission device delivers the capillary column into the storage box, the capillary column spontaneously forms a multi-layered figure-eight shaped structure within the storage box.

[0013] Furthermore, the first, second, and third storage boxes have small holes on their bodies to facilitate heat transfer; each storage box can store a 3-5 meter capillary chromatography column.

[0014] Furthermore, the first and second transmission devices have the same structure, including a stepper motor, a speed change mechanism, and two rollers connected in sequence. The stepper motor and the speed change mechanism drive the two rollers to rotate, thereby driving the capillary column to be fed into and out of the storage box.

[0015] Furthermore, the temperature control system controls the temperature between room temperature and -20°C; the transmission line is heated to 280-300°C to ensure that the components do not remain inside the transmission line.

[0016] The present invention also provides an operating method for a universal band width compression device based on gas chromatography kinetics, comprising the following steps:

[0017] At the beginning of the chromatographic analysis, most of the compressed column is stored in the first storage box. When the target component moves to the end of the high-temperature zone of the compressed column, the first transmission device is activated to transport the compressed column at a speed of 10-20 cm / min to the second storage box located in the low-temperature zone of the band compression assembly. After all the target components have been compressed, the second transmission device is activated to return the compressed column in the second storage box to the third storage box, which is directly connected to the detector and located in the high-temperature zone.

[0018] Furthermore, the peak width of the target component is compressed by 10-20 times, the detection sensitivity is improved by 10-20 times, and the separation of the target component is basically the same as that of using the analytical column alone.

[0019] The present invention also provides an application of a band width compression method based on gas chromatography kinetics, or a universal band width compression device based on gas chromatography kinetics, or an operation method of a universal band width compression device based on gas chromatography kinetics in improving gas chromatography sensitivity.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] 1. This invention provides a novel method for improving the sensitivity of gas chromatography: band width compression. It can improve sensitivity by more than 10 times without requiring instrument upgrades or adjustments to sample processing methods. This has significant application implications for improving gas chromatography analysis methods.

[0022] 2. This invention is easy to operate and highly automated.

[0023] 3. This invention has a simple structure and low price, and is suitable for improving the sensitivity of various capillary gas chromatography methods.

[0024] 4. This invention cleverly utilizes the difference in band movement speed and band broadening speed in the high and low temperature regions of gas chromatography to achieve band width compression. Furthermore, it leverages the mechanical movement of the capillary column from the high-temperature region to the low-temperature region to maintain essentially constant resolution by trading space for time. Ultimately, it can achieve a 10-20 fold increase in sensitivity while maintaining the same separation effect. Based on this method, this invention constructs a compact and universal gas chromatography band width compression device with a wide range of applications. This device can improve sensitivity by more than 10 times compared to various existing gas chromatographs and methods, and has broad application prospects.

[0025] In summary, this invention provides a new technical solution that is independent of and compatible with other sensitivity enhancement methods. This invention can be applied alone or in combination with other methods. Regardless of the advancements in other methods, this invention can further improve sensitivity by 10-20 times. This is of great significance to the development of gas chromatography analysis technology. Based on the above reasons, this invention can be widely promoted in fields such as gas chromatography analysis. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the bandwidth compression device of the present invention.

[0028] Figure 2 This is the chromatogram of the bands before compression in Example 1 of the present invention.

[0029] Figure 3 This is the chromatogram after band compression in Example 1 of the present invention.

[0030] Figure 4 This is a schematic diagram showing the storage of capillary columns in the storage box of the present invention.

[0031] In the diagram: 1. Band compression assembly; 2. Column oven; 3. Analytical column; 4. Compression column; 5. First storage box; 6. Second storage box; 7. Third storage box; 8. First transmission device; 9. Second transmission device; 10. Temperature control system; 11. Transmission line; 12. Detector. Detailed Implementation

[0032] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0035] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0036] To improve the sensitivity of capillary gas chromatography, this invention provides a band width compression method based on gas chromatography kinetics, a compression device, its operation method, and its application. Specifically, it presents a band width compression method based on gas chromatography kinetics, a universal band width compression device, its operation method, and its application in improving gas chromatography sensitivity. A universal capillary column band width compression method based on chromatographic kinetics is proposed, and a corresponding device is constructed. Applying this device to capillary gas chromatography analysis can improve sensitivity by 10-20 times without significantly affecting resolution. More specifically, this invention provides a universal gas chromatography band width compression method, a universal capillary column chromatography band width compression device, its operation method, and its application.

[0037] This invention proposes a novel method for capillary gas chromatography analysis, based on chromatographic kinetics: a band width compression method, and constructs a corresponding device. According to the chromatographic theory formula (1), the plate height, which is positively correlated with band width, is affected by the following factors: A is the eddy diffusion term, B is the longitudinal diffusion term, and C is the mass transfer resistance term. For capillary gas chromatography, B is the dominant influencing factor. The broadening of the gas chromatographic band mainly occurs in the longitudinal diffusion near the effluent temperature. Introducing the target band that has been separated into a low-temperature region (with a temperature difference of more than 100°C from the effluent temperature) allows for band width compression due to the simultaneous rapid decrease in band movement speed and longitudinal diffusion. During the compression process, the compression column is continuously and uniformly transported from the high-temperature region to the low-temperature region at a speed of 10-20 cm / min, trading space for time, which ensures that the resolution of adjacent chromatographic peaks remains essentially unchanged.

[0038]

[0039] Compression of the band width of mass detectors (FID, ECD) results in a proportional increase in mass concentration (mass / time), thus the sensitivity will be improved by 10-20 times after band compression.

[0040] This invention provides a novel band width compression device based on gas chromatography kinetics. Connecting this device to a capillary gas chromatograph allows for a 10-20 fold reduction in peak width without significantly affecting target analyte resolution. According to the principle of mass conservation, the reduction in band width will proportionally increase the component's mass concentration (mass / time). Ultimately, gas chromatography using mass-based detectors (FID, ECD, etc.) can achieve a 10-20 fold increase in detection sensitivity with the aid of this band width compression device.

[0041] The principle of the universal capillary gas chromatography band width compression device of the present invention is as follows: a suitable mechanical transmission device is used to move the capillary column from the chromatograph oven into the low temperature zone of the compression component, and the band width is compressed by utilizing the huge difference in the retention and band movement speed of the components at the normal separation column temperature zone and the low temperature zone of the compression component.

[0042] The device of this invention includes a capillary column mechanical transmission mechanism, a capillary column storage box, a temperature controller, and a transmission line for connecting the device to a gas chromatograph (the transmission line connects the compression assembly box to a conventional gas chromatograph). When the target band reaches the end of the high-temperature zone of the compression column (i.e., column 2, the capillary column), the transmission mechanism 1 (i.e., the first transmission mechanism) is activated to transport the column at an appropriate speed to the low-temperature zone of the compression assembly box (i.e., the band compression assembly 1). After all target components have been compressed, the transmission mechanism 2 (i.e., the second transmission mechanism) is activated to return the low-temperature compressed column to the high-temperature zone directly connected to the detector. Through this process, the peak width of the target components is compressed by 10-20 times, the detection sensitivity is improved by 10-20 times, and the resolution of the target components is essentially the same as when using column 1 alone. The compression assembly box has a built-in temperature controller that can be set to room temperature - -20°C.

[0043] This invention discloses a universal capillary gas chromatography band width compression device, specifically comprising: capillary column storage boxes 1, 2, and 3 (i.e., first storage box 5, second storage box 6, and third storage box 7); capillary transmission devices 1 and 2 (i.e., first transmission device 8 and second transmission device 9); a temperature control system (used to achieve the required temperature in the device's operating area, capable of controlling the temperature down to -20°C); and two transmission lines 11 (heated to 280-300°C to ensure that components do not remain within the transmission lines). The second storage box 6, the temperature control system 10, and the two transmission devices are disposed in the band compression assembly 1 (the second storage box 6 is located in the low-temperature zone of the band compression assembly box), while the first storage box 5 and the third storage box 7 are disposed in the high-temperature zone of the gas chromatograph column oven 2 (i.e., the gas chromatography furnace oven). The column oven 2 also contains a column 1 (a common analytical column 3, used for gas chromatographic separation of target components) and a detector 12, the detector 12 being connected to the third storage box 7. Two transmission lines 11 connect the band compression assembly 1 and the gas chromatograph. During the transport of the compression column 4, it passes through both transmission lines 11. Three storage boxes store the compression column at different stages of the operation. The compression column 4 is used to compress the target component's band width. Initially, it is stored in the first storage box 5. The starting end of the compression column 4 is connected to the analytical column 3, which is used for gas chromatographic separation of the target component. The carrier gas is transported to the compression column 4 through the analytical column 3. A first transmission device 8 transports the compression column 4 from the first storage box 5 through the transmission line 11 to the second storage box 6. A second transmission device 9 transports the compression column 4 from the second storage box 6 through the transmission line 11 to the third storage box 7. The compression column 4 in the third storage box 7 is connected to the detector 12. The first transmission device 8 and the second transmission device 9 have the same structure, including a stepper motor, a speed change mechanism and two rollers connected in sequence. The stepper motor and the speed change mechanism drive the two rollers to rotate, which in turn drives the capillary column to be fed into and out of the storage box. The capillary column moves between the two rollers.

[0044] Preferably, a graphite tube of suitable inner diameter is used to guide the capillary column into and out of a flat metal box (with small holes in the box to facilitate heat transfer). When the transport device delivers the capillary column into the storage box, the capillary column, due to its own elasticity, will spontaneously form a multi-layered figure-eight structure. This allows a 3-5 meter chromatographic column to be stored in a reasonably sized storage box within a gas chromatography oven without affecting its normal use. Figure 4 The image shows the capillary column storage situation, photographed using a cardboard box of the same shape (with a transparent top surface).

[0045] The present invention relates to an operating method for a universal band width compression device based on gas chromatography kinetics. The steps are as follows: At the beginning of the chromatographic analysis, most of the column 2 is stored in the box 1. When the target component reaches the end of the column 2 in the high-temperature zone, the transfer device 1 is activated to transfer the column 2 to the low-temperature zone box 2 of the compression assembly box at a suitable speed (10-20 cm / min). After all the target components have been compressed, the transmission device 2 is activated to return the compressed column in the box 2 to the box 3, which is directly connected to the detector and located in the high-temperature zone. Through this process, the peak width of the target component is compressed by 10-20 times, the detection sensitivity is improved by 10-20 times, and the resolution of the target component is basically the same as when using the column 1 alone.

[0046] The present invention also provides an application of a band width compression method based on gas chromatography kinetics, or a universal band width compression device based on gas chromatography kinetics, or an operation method of a universal band width compression device based on gas chromatography kinetics in improving gas chromatography sensitivity.

[0047] The advantages of the device of the present invention are: 1. Low cost, compact structure and light weight; 2. Simple to use and highly automated; 3. Wide range of applications, capillary gas chromatography using mass detectors can improve sensitivity by 10-20 times with the help of this device.

[0048] Example 1

[0049] according to Figure 1 The device structure shown connects the various components to obtain the universal capillary gas chromatography band width compression device of the present invention. The gas chromatograph is an HP5890, equipped with an FID detector, and the signal acquisition frequency is 20Hz. The analytical column (column 1) is DB5 (30m*0.25mm); the compression column (column 2) is DB5 (1.2m*0.25mm); the injection port temperature is 280℃, the detector temperature is 280℃, and the split ratio is 100:1; the temperature control of the compression device maintains room temperature.

[0050] Figure 2This is a normal gas chromatogram without band compression. The target components are four chromatographic peaks (1, 2, 3, 4) with retention times between 11 and 12 min. The actual compression process using the device of this invention is as follows: At the beginning of the chromatographic analysis, the 0.9M column 2 is stored in box 1 (first storage box). When the injection timer starts, at 10.20 min, the transfer device 1 (first transmission device) is activated to transfer column 2 to box 2 (second storage device) in the compression assembly box at a speed of 15 cm / min. After 12.5 min, the compression is completed, and the transmission device 2 (second transmission device) is activated to return the compressed column in box 2 to box 3 (third storage box) which is directly connected to the detector. Figure 3 This is the effect after using the band compression device. As can be seen from the figure, the band width was reduced by more than 10 times, and the sensitivity was also increased by approximately 10 times accordingly. At the same time, the resolution of the four chromatographic peaks remained basically unchanged after band compression (the resolution of peaks 2 and 3 decreased slightly, but had no effect on the quantitative integral). In summary, the band compression device achieved good results in this embodiment, increasing the sensitivity by 10 times without significantly affecting the resolution.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A universal band width compression device based on gas chromatography kinetics, characterized in that, By utilizing the difference in the speed of movement and the speed of band broadening in the high and low temperature regions of gas chromatography, the band width is compressed. At the same time, the mechanical movement of the capillary column from the high temperature region to the low temperature region is used to trade space for time and maintain the resolution basically unchanged. The capillary column is moved from the high-temperature zone of the gas chromatograph oven to the low-temperature zone of the compression assembly by a mechanical transmission device. By utilizing the difference in retention and band movement speed of the components at the normal separation column temperature zone and the low-temperature zone of the compression assembly, the band width is compressed by the simultaneous and rapid decrease in band movement speed and longitudinal diffusion. The general band width compression device based on gas chromatography kinetics includes: a band compression assembly (1), a transmission line (11), and a first storage box (5) and a third storage box (7) disposed in the column oven (2) of the gas chromatograph. The transmission line (11) is used to connect the band compression assembly (1) and the gas chromatograph. The band compression assembly (1) includes a second storage box (6), a first transmission device (8), a second transmission device (9), and a temperature control system (10). The first storage box (5), the second storage box (6), and the third storage box (7) are used to store the compression column (4). The third storage box (7) is connected to the detector (12) in the column oven (2). The compression column (4) is used to compress the target component band width. The initial stage is stored in the first storage box (5). The starting end of the compression column (4) is connected to the analysis column (3) in the column oven (2). The analysis column (3) is used for gas chromatography separation of the target component. The carrier gas is transported to the compression column (4) through the analysis column (3). The first transmission device (8) is used to transmit the compression column (4) in the first storage box (5) located in the high temperature zone through the transmission line (11) to the second storage box (6) located in the low temperature zone. The second transmission device (9) is used to transmit the compression column (4) in the second storage box (6) through the transmission line (11) to the third storage box (7) located in the high temperature zone. The compression column (4) transmitted to the third storage box (7) is connected to the detector (12).

2. The universal band width compression device based on gas chromatography kinetics according to claim 1, characterized in that, The first storage box (5), the second storage box (6) and the third storage box (7) are all flat metal boxes. The capillary chromatographic column is introduced into the flat metal box and led out from the flat metal box using a graphite tube. When the transmission device delivers the capillary column into the storage box, the capillary column spontaneously forms a multi-layered figure-eight shaped structure within the storage box.

3. The universal band width compression device based on gas chromatography kinetics according to claim 1 or 2, characterized in that, The first storage box (5), the second storage box (6) and the third storage box (7) have small holes on their bodies; each storage box can store a 3-5 meter capillary chromatography column.

4. The universal band width compression device based on gas chromatography kinetics according to claim 1, characterized in that, The first transmission device (8) and the second transmission device (9) have the same structure, including a stepper motor, a speed change mechanism and two rollers connected in sequence. The stepper motor and the speed change mechanism drive the two rollers to rotate, thereby driving the capillary column to be fed into and out of the storage box.

5. The universal band width compression device based on gas chromatography kinetics according to claim 1, characterized in that, The temperature control system (10) controls the temperature between room temperature and -20°C; the transmission line (11) is heated to 280-300°C to ensure that the components do not remain in the transmission line (11).

6. A method for operating the universal band width compression device based on gas chromatography kinetics as described in any one of claims 1-5, characterized in that, Includes the following steps: At the beginning of the chromatographic analysis, most of the compressed column (4) is stored in the first storage box (5). When the target component moves to the end of the high temperature zone of the compressed column (4), the first transmission device (8) is activated to transport the compressed column (4) at a speed of 10-20 cm / min to the second storage box (6) located in the low temperature zone of the band compression assembly (1). After all the target components have been compressed, the second transmission device (9) is activated to return the compressed column (4) in the second storage box (6) to the third storage box (7) which is directly connected to the detector (12) and located in the high temperature zone.

7. The operating method of the universal band width compression device based on gas chromatography kinetics according to claim 6, characterized in that, The peak width of the target component is compressed by 10-20 times, the detection sensitivity is improved by 10-20 times, and the separation of the target component is basically the same as that of the analytical column (3) alone.

8. The application of a universal band width compression device based on gas chromatography kinetics as described in any one of claims 1-5, or the operating method of a universal band width compression device based on gas chromatography kinetics as described in any one of claims 6-7, in improving gas chromatography sensitivity.

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