CN118348176A - Sampling method and sampling system of automatic sampler - Google Patents

Abstract

The invention discloses a sample injection method and a sample injection system of an automatic sample injector, wherein the sample injection system comprises a six-way valve, a metering pump, a sample injection needle seat and a mobile phase, wherein the six-way valve is provided with a first interface, a second interface, a third interface, a fourth interface, a fifth interface and a sixth interface which are distributed clockwise, the metering pump is connected with the second interface, the mobile phase is connected with the third interface, and the sample injection needle seat is connected with the fifth interface. According to the sample injection method, the pump is driven to drive the mobile phase to move, and the metering pump has the drawing action in the opposite direction, so that the speed of the mixed liquid of the mobile phase and the sample solvent entering the chromatographic column can be slowed down, the stability of the peak-out spectrum of the liquid phase system is ensured, and the stability of the detection result is ensured.

Description

Sampling method and sampling system of automatic sampler

Technical Field

The invention relates to an automatic injection technique for liquid chromatography, in particular to an injection method and an injection system for an automatic injector.

Background technique

In liquid phase reactions, solvent effects are often encountered. The so-called solvent effect refers to the effect of the physical and chemical properties of the solvent on the reaction equilibrium and reaction rate in liquid phase reactions. The essence of solvation is mainly electrostatic. For neutral solute molecules, the heterolytic cleavage of covalent bonds will cause the separation of charges. Therefore, increasing the polarity of the solvent has a greater impact on the solute, which can reduce the energy of the transition state, resulting in a reduction in the activation energy of the reaction and a significant increase in the reaction rate.

At present, some manufacturers use the "sandwich injection" method, in which a small amount of mobile phase is inhaled before and after the sample is sucked, allowing the mobile phase to contact the sample solvent in the low-pressure area in advance. When the sample is cut from low pressure to high pressure, the mobile phase and the sample solvent are quickly mixed to achieve the effect of optimizing the peak shape spectrum. However, this method will inhale the protective solution twice, and the injection action is too cumbersome. The volume of the inhaled protective solution will occasionally affect the results.

Summary of the invention

In order to solve the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide an injection method and injection system for an automatic sampler, which can reduce the solvent effect and ensure the stability of the liquid phase system detection results without increasing excessive injection actions.

The technical solution adopted by the present invention to solve the technical problem is: a sampling method of an automatic sampler comprises the following steps:

The injection needle and the metering pump are switched to the low pressure zone through the six-way valve, and the injection needle is connected to the sample bottle;

Extract a quantitative sample through a metering pump;

The injection needle and the metering pump are switched to the high pressure zone through the six-way valve, the metering pump is connected to the driving pump of the liquid chromatography, and the injection needle is connected to the injection needle seat;

The mobile phase is driven by a driving pump to move, so that the mobile phase mixes with the sample and moves toward the chromatographic column;

Wherein, while the driving pump drives the mobile phase to move, the driving end of the metering pump moves in the opposite direction to the movement of the mobile phase.

Optionally, when the metering pump is in the low-pressure zone, one end of the metering pump connected to the six-way valve is in a blocked state, and one end of the injection needle seat connected to the six-way valve is in a blocked state.

Based on the above-mentioned injection method, the present invention also provides an injection system of an automatic sampler, including a six-way valve, a metering pump, an injection needle, an injection needle seat and a mobile phase, wherein the six-way valve has a first interface, a second interface, a third interface, a fourth interface, a fifth interface and a sixth interface distributed in a clockwise direction, wherein the metering pump is connected to the second interface, the mobile phase is connected to the third interface, and the injection needle seat is connected to the fifth interface.

By adopting the above technical scheme, the injection method of the present invention, while the driving pump drives the mobile phase to move, the metering pump has a pulling action in the opposite direction, which can slow down the speed at which the mixed liquid of the mobile phase and the sample solvent enters the chromatographic column, thereby ensuring the stability of the peak spectrum of the liquid phase system and the stability of the detection results.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a state diagram of the present invention during sampling;

FIG. 2 is a state diagram of the present invention during sample injection.

Detailed ways

The present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant inventions, rather than to limit the inventions. It should also be noted that, for ease of description, only the parts related to the invention are shown in the accompanying drawings.

It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

As shown in Figures 1 and 2, the present invention discloses an injection system of an automatic sampler, including a six-way valve 100, a metering pump 200, an injection needle 300, an injection needle seat 400 and a mobile phase. The six-way valve 100 has a first interface, a second interface, a third interface, a fourth interface, a fifth interface and a sixth interface distributed in a clockwise direction, wherein the metering pump 200 is connected to the second interface, the mobile phase is connected to the third interface, and the injection needle seat 400 is connected to the fifth interface. The metering pump 200 is connected by this connection method, so that two connection ports are spaced between the metering pump 200 and the injection needle seat 400, and the metering pump 200 is adjacent to the mobile phase. Therefore, when the injection needle 300 is switched to the high-pressure zone, the metering pump 200 can be switched to the high-pressure zone synchronously, so as to facilitate the control of the metering pump 200 in the high-pressure zone, that is, when the mobile phase is moving, the driving end of the metering pump 200 can be controlled to move in the opposite direction, thereby slowing down the flow rate of the mobile phase and the sample solvent entering the chromatographic column. This connection method not only avoids the complicated injection steps, but also reduces the solvent effect.

The six-way valve of the present invention is based on the above-mentioned connection mode, and the liquid phase system has a sampling state and an injection state. When in the sampling state, the metering pump 200 and the injection needle 300 are in a low-pressure area, and at this time, the end of the metering pump 200 connected to the six-way valve 100 is in a blocked state, and the end of the injection needle seat 400 connected to the six-way valve 100 is in a blocked state, and when in the injection state, the metering pump 200 and the injection needle 300 are in a high-pressure area. Therefore, using the above-mentioned connection mode, when the liquid phase system is injected, it is divided into two steps, namely, sampling and injection.

When sampling, the sampling steps are:

S1, switch the injection needle 300 and the metering pump 200 to the low pressure area through the six-way valve 100, and connect the injection needle 300 to the sample bottle;

S2. A quantitative sample is extracted through the metering pump 200.

When performing injection, the injection steps are:

S1, switching the injection needle 300 and the metering pump 200 to the high pressure zone through the six-way valve 100, connecting the metering pump 200 to the driving pump of the liquid chromatography, and connecting the injection needle 300 to the injection needle seat 400;

S2. The mobile phase is driven by a driving pump so that the mobile phase mixes with the sample and moves toward the chromatographic column.

S2a. While the driving pump drives the mobile phase to move, the driving end of the metering pump 200 moves in the opposite direction to the movement of the mobile phase.

The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with the technical features with similar functions disclosed in this application (but not limited to) by each other.

Except for the technical features described in the specification, the remaining technical features are known technologies to those skilled in the art. In order to highlight the innovative features of the present invention, the remaining technical features will not be described here in detail.

Claims (3)

1. The sample injection method of the automatic sample injector is characterized by comprising the following steps,

Switching the sample injection needle and the metering pump to a low-pressure area through a six-way valve, and connecting the sample injection needle with a sample bottle;

extracting a quantitative sample by a metering pump;

Switching the sample injection needle and the metering pump to a high-pressure area through a six-way valve, so that the metering pump is connected with a driving pump of liquid chromatograph, and the sample injection needle is connected with a sample injection needle seat;

driving the mobile phase to move by driving the pump, so that the mobile phase mixes the sample and moves to the chromatographic column;

Wherein, the driving end of the metering pump moves towards the direction opposite to the moving direction of the mobile phase when the pump is driven to drive the mobile phase to move.

2. The method of claim 1, wherein when the metering pump is in the low pressure region, the end of the metering pump connected to the six-way valve is in a blocked state, and the end of the sample injection needle holder connected to the six-way valve is in a blocked state.

3. The sampling system of the automatic sampler is characterized by comprising a six-way valve, a metering pump, a sampling needle seat and a mobile phase, wherein the six-way valve is provided with a first interface, a second interface, a third interface, a fourth interface, a fifth interface and a sixth interface which are distributed clockwise, the metering pump is connected with the second interface, the mobile phase is connected with the third interface, and the sampling needle seat is connected with the fifth interface.