Sample injection needle of automatic sample injector of liquid chromatograph

Abstract

The utility model discloses a sample injection needle of an automatic sample injector of a liquid chromatograph, and belongs to the technical field of chromatographic instruments. The sleeve is arranged outside the needle body of the sample injection needle, the needle outlet is formed in the bottom of the sleeve, in the sample injection process, the sleeve firstly makes contact with and penetrates through a shock insulator of a sample bottle, then the sample injection needle body enters the sample bottle, and the structural design can effectively solve the problem that the sample injection opening in the needle point is blocked due to shock insulator chippings. Besides, the cleaning opening is formed in the side wall of the sleeve, so that the outer wall of the needle body can be cleaned in all directions and dried efficiently, and the risk of cross contamination among samples caused by liquid residues on the outer wall is effectively avoided.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of chromatograph, concretely is a kind of sample injection needle of liquid chromatograph automatic sample injector. BACKGROUND

[0002] Sample injection needle is indispensable component of liquid chromatograph automatic sample injector, and traditional sample injection needle occupies quite long historical period in the field of liquid chromatographic analysis by virtue of its simple design pattern of straight in and straight out. This design is widely favored due to its intuitive and easy to manufacture features. However, the structure of the opening directly at the needle tip becomes its significant weakness, as the opening is easily blocked by septum debris when the needle tip penetrates the septum into the sample bottle. To overcome this problem, side outlet sample injection needle emerges as the times require, and its opening design is ingeniously moved above the needle tip, effectively avoiding the clogging problem of traditional sample injection needle, and significantly improving the stability and reliability of the analysis process. However, despite the significant progress made by side outlet sample injection needle in solving the clogging problem, it still has certain limitations in practical application. Specifically, due to the design of the side opening, the sample injection needle needs to ensure that the liquid in the bottle reaches a certain height when sucking liquid, which to some extent limits its application in cases where the sample amount is small, and thus may have some impact on the accuracy of the analysis results.

[0003] On the other hand, in the continuous sample injection analysis process, to avoid cross contamination affecting the accuracy of the analysis results, the sample injection needle must be cleaned after completing the delivery of a sample. The current automatic sample injector uses bypass sampling, and the automatic cleaning mechanism is not perfect, mainly relying on continuous liquid suction and discharge actions to clean the inner wall of the needle. However, as for the cleaning of the outer wall of the needle, manual operation or simple rinsing treatment during the inner wall cleaning process is usually required, and the effect of this cleaning method is not stable, which cannot ensure the thorough cleaning of the sample injection needle, and thus may interfere with the accuracy of the experimental results. SUMMARY

[0004] In view of the deficiencies of the prior art, the present utility model provides a sample injection needle for a liquid chromatograph automatic sample injector, which aims to solve the problem of easy clogging of the existing traditional sample injection needle by septum debris and the technical problem of easy contamination caused by liquid residue on the outer wall of the needle.

[0005] To achieve the above-mentioned purpose, the utility model provides a sample injection needle for a liquid chromatograph automatic sample injector, which comprises a needle body, a needle seat and a sleeve, the needle body is fixedly connected to the needle seat at the top by a nut, the main body of the needle body is arranged in the sleeve, the needle tip of the needle body is provided with a sample injection port, the inner diameter of the sleeve is greater than the outer diameter of the needle body, the bottom of the sleeve is provided with a needle outlet, and the outer wall of the nut is further connected to the sleeve in an up-and-down movable manner.

[0006] Preferably, the nut outer wall and the sleeve are threadedly connected.

[0007] Preferably, the bottom of the sleeve is provided with a pointed end capable of penetrating the septum of the sample bottle.

[0008] Preferably, the pointed end is conical.

[0009] Preferably, the sleeve is made of stainless steel.

[0010] Preferably, the side wall of the sleeve is provided with a cleaning opening.

[0011] Preferably, the sample inlet is located below the needle tip of the needle body.

[0012] Preferably, a plug assembly is arranged between the needle body and the sleeve.

[0013] Preferably, the plug assembly is made of PEEK.

[0014] Compared with the prior art, the beneficial technical effects realized by the utility model are:

[0015] 1. In the sampling process, the sleeve of the sampling needle first contacts and penetrates the septum of the sample bottle, and then the needle body enters the sample bottle to take samples. This design effectively avoids the problem that the needle tip of the sampling needle directly penetrates the septum, causing the sampling inlet to be easily blocked by septum debris. At the same time, because the sampling inlet of the sampling needle is arranged below the needle tip, it ensures that liquid can be completely absorbed and sampled even in the case of small liquid volume, solving the problem of the limitation of sample volume when using the traditional side outlet sampling needle, and ensuring the accuracy of the analysis result when the sample volume is small.

[0016] 2. The side wall of the sleeve is provided with a cleaning opening, and a cleaning liquid can be injected to clean the outer wall of the needle body. The cleaning waste liquid is discharged through the needle outlet at the bottom of the sleeve. Then, a gas is injected at the cleaning opening to dry the outer wall of the needle body, realizing the all-round cleaning and efficient drying of the outer wall of the sampling needle. This measure significantly reduces the risk of cross contamination between samples caused by liquid residues on the outer wall. BRIEF DESCRIPTION OF DRAWINGS

[0017] Fig. 1 is a sectional view of the needle body and the sleeve of the sampling needle of an embodiment of the utility model;

[0018] Fig. 2 is a schematic structural view of the sampling needle structure of an embodiment of the utility model, in which the needle body does not extend out of the sleeve;

[0019] Fig. 3 is a schematic structural view of the sampling needle structure of an embodiment of the utility model, in which the needle body extends out of the sleeve;

[0020] Fig. 4 is a schematic structural view of the overall structure of the needle body and the sleeve of the sampling needle of an embodiment of the utility model;

[0021] Reference numeral: 1, needle body; 2, sleeve; 3, cleaning port; 4, sample inlet; 5, plug assembly; 6, nut, 7, needle seat; 8, needle outlet. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme of the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are some embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts fall within the scope of protection of the present application.

[0023] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts fall within the scope of protection of the present application.

[0024] It should be noted that: similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0025] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting", "fixing" and the like should be understood broadly, for example, can be fixed connection, can also be detachable connection, or integral; can be directly connected, or indirectly connected through an intermediate medium; can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0026] In order to better understand the purpose, structure and function of the present application, the sample injection needle of the automatic sample injector of the liquid chromatograph of the present application will be described in further detail below in conjunction with the drawings.

[0027] Example 1

[0028] As Figs. 1-4As shown, the utility model provides a kind of sample injection needle of liquid chromatograph automatic sample injector, including needle body 1, needle seat 7, sleeve 2, needle body top is fixedly connected with needle seat 7 by nut 6, the main part of needle body 1 is arranged in sleeve 2, needle tip of needle body 1 is equipped with sample injection port 4, the inside diameter of sleeve 2 is greater than the outside diameter of needle body 1, so that certain gap is left between sleeve 2 and needle body 1, sleeve 2 bottom is equipped with needle outlet 8, the outer wall of nut 6 is also connected with sleeve 2 up and down lifting movable connection.

[0029] Further, the inner thread cavity fixedly connected of needle body 1 top end and the lower end of nut 6, the upper end of nut 6 is threadedly connected with needle seat 7;Nut 6 outer wall is equipped with external thread, sleeve 2 inner wall is equipped with internal thread, nut 6 is threadedly connected with sleeve 2 by the external thread of outer wall.

[0030] Further, the bottom of sleeve 2 is provided with a sharp end that can penetrate the sample bottle septum, for example, the sharp end of sleeve 2 can be conical.

[0031] Further, sleeve 2 is made of high hardness and corrosion-resistant material, for example, sleeve 2 can be made of stainless steel material.

[0032] Further, plug assembly 5 is provided between needle body 1 and sleeve 2 to ensure the sealing between needle body 1 and sleeve 2.

[0033] Further, the material of plug assembly 5 can be PEEK material.

[0034] Further, the sample injection port 4 is located below the needle tip of the needle body 1. It ensures that the liquid can be completely sampled even if the amount of liquid is small, and solves the problem of sample quantity limitation in practical use of traditional side outlet sample injection needle. The accuracy of the analysis result can be ensured even when the sample quantity is small.

[0035] The sample injection needle of the utility model is fixed by the sample injector device to realize the up-down movement of the whole sample injection needle, and the sleeve is controlled by the external mechanical arm to rotate clockwise or counterclockwise. The sleeve 2 can move up and down on the nut 6 to realize the up-down movement of the sleeve relative to the needle body.

[0036] The specific sampling process of the sample injection needle is as follows: in the sampling stage, the sample injection needle presents the initial state as shown in Fig. 2 The whole sample injection needle is controlled to descend by the sample injection device to penetrate the sample bottle cap septum and stop at a certain height from the liquid surface;Then the sleeve is rotated by the mechanical arm to ascend to the needle body from the sleeve and the sleeve does not penetrate the sample bottle, at this time, the sample injection needle presents Fig. 3The sample injection device controls the whole injection needle to continue to drop to a predetermined depth to suck the sample, and the sample injection system extracts the sample according to a preset program; after the sample extraction is completed, the whole injection needle is first lifted above the liquid surface by the sample injection device control, then the sleeve is controlled to rotate by the mechanical arm to make it drop into the needle body, finally the whole injection needle is controlled to leave the sample bottle by the sample injection device, and after the sampling is completed, the cleaning of the needle and the sleeve is completed. The design that the hard needle sleeve first penetrates the septum and then the needle body enters the sampling effectively protects the injection needle, avoids the risk that the needle tip sampling port is blocked by the septum of the sample bottle, and thus ensures the stability and reliability of the whole analysis process.

[0037] Embodiment 2

[0038] As Figs. 1-4 shown, the utility model provides a kind of injection needle of automatic sample injector of liquid chromatograph, and it is different from embodiment 1, and it is equipped with cleaning port 3 on sleeve 2 side wall, can introduce washing liquid and drying gas to clean and dry needle body outer wall.

[0039] Specific implementation process is as follows: after the injection needle completes single sampling, needle body inner wall and needle tip are cleaned first, and this part of cleaning sampling can be cleaned by the existing injection needle cleaning method. Then according to preset program, connect pipeline at cleaning port 3, inject cleaning liquid in the pipeline, cleaning liquid enters the gap between needle body 1 outside and sleeve 2 inner wall, fully rinses the outer wall of needle body 2, then cleaning liquid can be discharged from needle outlet 8 at the bottom of sleeve 2. After the outer wall of needle body 2 is cleaned, dry gas is connected to replace the pipeline to quickly dry the outer wall of needle body 2, so that the outer wall cleaning and drying of injection needle needle body are realized, the risk of cross contamination between samples caused by liquid residue on the outer wall is reduced, and the accuracy of experimental results is ensured.

[0040] The above only for the preferred embodiment of the utility model, and not for limiting the utility model, for the person skilled in the art, the utility model can have various changes and changes. Any modification, equivalent replacement, improvement etc. made within the spirit and principle of the utility model should be included in the protection scope of the utility model.

Claims

1. A sample introduction needle for an autosampler of a liquid chromatograph, characterized by, The utility model provides a needle body, needle seat, sleeve, the needle body top is fixedly connected with the needle seat through the nut, the needle body main part is arranged in the sleeve, the needle tip of needle body is equipped with the sample inlet, the inner diameter of sleeve is greater than the outer diameter of needle body, the bottom of sleeve is equipped with the needle outlet, the outer wall of nut is still connected with the sleeve up and down lift movable joint.

2. The sample injection needle of a liquid chromatograph automatic sampler according to claim 1, wherein, The outer wall of the nut is threadedly connected with the sleeve.

3. The sample injection needle of a liquid chromatograph automatic sampler according to claim 1, wherein, The bottom of the sleeve is provided with a sharp end capable of penetrating the septum of a sample bottle.

4. The sample introduction needle of claim 3, wherein, The sharp end is conical.

5. The sample injection needle of a liquid chromatograph automatic sampler according to claim 1, wherein, The sleeve is made of stainless steel.

6. The sample injection needle of a liquid chromatograph automatic sampler according to claim 1, wherein, The side wall of the sleeve is provided with a cleaning port.

7. The sample injection needle of a liquid chromatograph automatic sampler according to claim 1, wherein, The sample inlet is located below the needle tip of the needle body.

8. The sample introduction needle of claim 1, wherein, A plug assembly is provided between the needle body and the sleeve.

9. The sample introduction needle of claim 8, wherein, The plug assembly is made of PEEK.

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