CN114628222A - Sample injection device and method for direct mass spectrometry analysis of high-boiling-point components in liquid - Google Patents

Abstract

The invention provides a sample injection device and a method for direct mass spectrometry analysis of high-boiling point components in liquid. The sample introduction device for direct mass spectrometry comprises a sample bottle heating sleeve, a sample bottle, a vacuum extraction pipeline and a sample introduction pipeline, wherein the sample bottle heating sleeve is coated outside the sample bottle; two paths of gas outlets are formed in the top of the closed sample bottle, wherein one path of gas outlet is connected with the inlet end of a vacuum pipeline switch valve through a vacuum pumping pipeline, and the outlet end of the vacuum pipeline switch valve is connected with a vacuum pump; and the other path of gas outlet is connected with the inlet end of a purge gas pipeline switch valve through a purge gas pipeline, and the outlet end of the purge gas pipeline switch valve is connected with a sample inlet port of the mass spectrometer. According to the invention, a large amount of solvent components with low boiling points in the liquid sample are quickly removed by a stepped heating mode and a vacuum pumping device, and then the high-boiling-point components are efficiently gasified and subjected to mass spectrometry by quickly heating, so that the matrix effect can be effectively eliminated, and the detection sensitivity of the high-boiling-point components is improved.

Description

Sampling device and method for direct mass spectrometry analysis of high boiling point components in liquid

technical field

The invention relates to a mass spectrometry instrument and method, in particular to a mass spectrometry sampling device and method, in particular to a sampling device and method for direct mass spectrometry analysis of high-boiling point components in a liquid.

Background technique

Human activities continue to emit a large amount of organic pollutants into the environment, a large part of which are relatively stable high-boiling organic compounds, including semi-volatile organic compounds (SVOCs: boiling point is 170 ~ 350 ℃, vapor pressure is 1.3 × 10 ^-2 ～1.3×10 ^-8 kPa organic compounds) and less volatile organic compounds with higher boiling points, such as: polycyclic aromatic hydrocarbons, organic pesticides, polychlorinated biphenyls, polychlorinated dibenzodioxins, nitrobenzene Classes, phthalates, anilines and phenols, etc. High-boiling organic compounds have low saturated vapor pressure and poor biodegradability, and are ubiquitous in ambient atmosphere, water and soil, and most of them are biologically toxic, causing great harm to the environment and organisms, and some even have carcinogenic, teratogenic and Mutagenic effects. Reliable detection of these high-boiling organic compounds in the environment is a prerequisite for pollution prevention and remediation.

For the detection of environmental organic compounds, offline analysis is usually performed by means of chromatography or chromatography-mass spectrometry. Although this method is accurate, it requires a relatively complex preprocessing process, and the analysis is time-consuming and costly, and it is difficult to reflect the rapid temporal and spatial changes of organic pollutants. Direct mass spectrometry technology does not require or requires little sample pretreatment, and directly obtains the molecular weight information of the analyte. It has the advantages of high resolution and sensitivity, strong qualitative ability and fast analysis speed, and has been widely used in the online detection of complex mixtures. attention and recognition. In direct mass spectrometry, the sample components in the gas phase are usually introduced into the mass spectrometer ion source for ionization, and then mass analysis is performed. However, the saturated vapor pressure of high-boiling organic compounds is low, and the detection sensitivity of mass spectrometry for direct headspace injection of high-boiling organic compounds in liquids is low. Direct heating and gasification of liquid samples is a commonly used method for mass spectrometry analysis of high boiling point components (Patent No.: 201310684182.4), but its disadvantage is that, on the one hand, the presence of a large amount of solvent (such as water) will lead to ionization and detection in mass spectrometry. On the other hand, the low content of high boiling point components does not have the effect of concentration and enrichment, and the sensitivity of direct detection will be affected. In addition, using the principle of ultrasonic atomization, the liquid sample is atomized into an aerosol state, and the high-boiling organic compounds in the liquid can enter the mass spectrometer for rapid analysis and detection under the purging action of the carrier gas (Patent No. 201711203610.1), but this method There are also the matrix effects of the solvent, and the problem of low detection sensitivity of low-content high-boiling components.

Based on this, the present invention uses a stepwise heating method and a vacuum pumping device to first rapidly volatilize and remove a large number of low-boiling solvent components in the liquid sample at a relatively low temperature, retain high-boiling components, and then rapidly increase the temperature. The high-boiling point components are efficiently vaporized and directly entered into the mass spectrometer for analysis.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a sample introduction device and method for direct mass spectrometry analysis of high boiling point components in liquid.

To achieve the above object, the technical scheme adopted in the present invention is:

A sample introduction device for direct mass spectrometry analysis of high-boiling point components in a liquid, comprising a sample bottle heating jacket, a sample bottle, a vacuum pumping pipeline and a sample introduction pipeline, and the sample bottle heating jacket is covered outside the sample bottle;

A sample introduction device for direct mass spectrometry analysis of high-boiling point components in a liquid, comprising a sample bottle heating jacket, a sample bottle, a vacuum pumping pipeline and a sample introduction pipeline, and the sample bottle heating jacket is covered outside the sample bottle;

There are two gas outlets on the top of the closed sample bottle, one of which is connected to the inlet end of a vacuum pipeline switch valve through a vacuum pumping pipeline, and a vacuum pump is connected to the outlet end of the vacuum pipeline switch valve; The purge gas pipeline is connected to the inlet end of a purge gas pipeline switch valve, and the outlet end of the purge gas pipeline switch valve is connected to the injection port of the mass spectrometer;

A sampling pipeline heating jacket is arranged outside the sampling pipeline and the opening and closing valve of the sampling pipeline;

A gas inlet is arranged on the side wall of the sample bottle, which is connected with the outlet end of a purge gas pipeline switch valve through a purge gas pipeline, and the inlet end of the purge gas pipeline switch valve is connected with the purge gas source.

The sample bottle is filled with a liquid sample; the gas inlet connected to the purge gas pipeline on the side wall of the sample bottle is arranged above the liquid surface of the liquid sample.

The sample bottle heating jacket is composed of an insulating material layer covering the outer wall of the sample bottle, and an electric heating element between the outer wall of the sample bottle and the insulating material layer;

The heating jacket of the injection pipeline is composed of a thermal insulation material layer covering the outer wall of the injection pipeline, and an electric heating element located between the outer wall of the injection pipeline and the thermal insulation material layer;

The insulating material is one or more of glass fiber, asbestos, rock wool, and aerogel felt;

The electric heating element is one or more of electric heating wire, electric heating belt and electric heating rod;

The heating temperature of the sample bottle heating jacket is from room temperature to 500°C, and the heating temperature of the purge gas pipeline (13) is from room temperature to 500°C.

The flow rate of the purging gas flowing out of the purging gas source is 0-1 L/min.

A sample introduction method for realizing direct mass spectrometry analysis of high-boiling point components in liquid by using the above-mentioned device, comprising the following steps:

Fill the sample bottle with the liquid sample to be tested;

Use the sample bottle heating jacket to heat the sample bottle and the liquid sample to room temperature to less than 150 °C, close the on-off valve of the injection line and the on-off valve of the purge gas line, and open the on-off valve of the vacuum line and the vacuum pump;

Maintain for 0.1 to 100 minutes to fully vaporize the low-boiling volatile components in the liquid sample and discharge them through a vacuum pump;

Quickly heat the sample bottle heating jacket to 150°C to 500°C, close the vacuum line switch valve and vacuum pump at the same time, and open the injection line switch valve and purge gas line switch valve;

After the high-boiling point components in the liquid sample are vaporized at high temperature, under the carrier band of the purge gas, they enter the mass spectrometer through the sampling pipeline and the opening and closing valve of the sampling pipeline for detection.

The present invention is aimed at the direct mass spectrometry analysis of high-boiling point components in the liquid, and adopts a stepwise heating method. First, the liquid sample is heated to a relatively low temperature (below 150° C.), and a vacuum suction device is added to extract the headspace gas, and the volatilized gas is extracted. The outgoing gas components are quickly discharged, and a large amount of low-boiling point solvent components in the liquid sample are quickly and efficiently removed, while the high-boiling point components are retained. Then, rapidly heat up to a higher temperature (150°C ~ 500°C) to efficiently vaporize the remaining high boiling point compounds, close the vacuum pumping device, and use the carrier gas to carry the vaporized high boiling point compounds into the mass spectrometer directly. analyze. The device and method of the present invention have outstanding advantages and effects:

1) When the low-boiling point solvent in the liquid volatilizes at a relatively low temperature, combined with vacuum headspace evacuation, the volatilization speed of the low-boiling point solvent can be greatly increased, and the entire treatment time can be shortened.

2) The low-boiling-point solvent components, which account for most of the liquid, are removed first, which can effectively eliminate the matrix effect. At the same time, it can concentrate and enrich the high-boiling-point components, thereby improving the detection sensitivity of the high-boiling-point components.

3) The device and the method are simple, the operation is convenient and flexible, and the scope of application is wide.

Description of drawings

Fig. 1 is the structural representation of the device of the present invention; in the figure: 1 is a sample bottle heating jacket, 2 is a sample bottle, 3 is an ultraviolet light source, 4 is a liquid sample, 5 is a vacuum pipeline switch valve, 6 is a vacuum pump, and 7 is a purge Gas pipeline, 8 is the purge gas pipeline switch valve, 9 is the sample injection pipeline heating jacket, 10 is the mass spectrometer, 11 is the purge gas source, 12 is the purge gas pipeline switch valve, and 13 is the purge gas pipeline.

FIG. 2 is a schematic diagram of a sample injection method for realizing direct mass spectrometry analysis of high-boiling point components in a liquid by using the above device according to the present invention.

Detailed ways

Please refer to FIG. 1, which is a schematic structural diagram of a sample introduction device for direct mass spectrometry analysis of high-boiling point components in a liquid of the present invention, including a sample vial heating jacket 1, a sample vial 2, a vacuum pumping line 4 and a sample injection line 7, and the sample vial The heating jacket 1 is wrapped on the outside of the sample bottle 2;

There are two gas outlets on the top of the sealed sample bottle, wherein one gas outlet is connected with the inlet end of a vacuum pipeline switch valve 5 through the vacuum pumping pipeline 4, and the outlet end of the vacuum pipeline switch valve 5 is connected with a vacuum pump 6; The gas outlet is connected with the inlet end of a purge gas pipeline switch valve 8 through the purge gas pipeline 7, and the outlet end of the purge gas pipeline switch valve 8 is connected with the injection port of the mass spectrometer 10;

A sampling pipeline heating jacket 9 is arranged outside the sampling pipeline 7 and the sampling pipeline on-off valve 8;

A gas inlet is provided on the side wall of the sample bottle 2, which is connected to the outlet end of a purge gas pipeline switch valve 12 through a purge gas pipeline 13, and the inlet end of the purge gas pipeline switch valve 12 is connected to the purge gas source 11. connected.

The sample bottle 2 is filled with a liquid sample 3 ; the gas inlet connected to the purge gas pipeline 13 on the side wall of the sample bottle 2 is arranged above the liquid level of the liquid sample 3 .

The heating temperature of the sample bottle heating jacket 1 is from room temperature to 500°C, and the heating temperature of the purge gas pipeline (13) is from room temperature to 500°C.

The flow rate of the purging gas flowing out of the purging gas source 11 is 0-1 L/min.

A method for implementing direct mass spectrometry analysis of high-boiling point components in a liquid using the above-mentioned device comprises the following steps:

Load the liquid sample 3 to be tested into the sample bottle 2;

Use the sample bottle heating jacket 1 to heat the sample bottle 2 and the liquid sample 3 to room temperature to less than 150°C, close the on-off valve 8 of the injection pipeline and the on-off valve 12 of the purge gas pipeline, and open the on-off valve 5 of the vacuum pipeline and the vacuum pump 6;

Maintain for 0.1 ~ 100min, so that the low-boiling volatile components in the liquid sample 3 are fully vaporized and discharged through the vacuum pump;

Quickly heat the sample bottle heating jacket 1 to 150°C to 500°C, close the vacuum line switch valve 5 and vacuum pump 6 at the same time, and open the sample injection line switch valve 8 and the purge gas line switch valve 12;

After the high-boiling point components in the liquid sample 3 are vaporized at high temperature, they enter the mass spectrometer 10 for detection through the sampling pipeline 7 and the sampling pipeline switching valve 8 under the carrier band of the purge gas.

Claims (5)

1. A sample introduction device for direct mass spectrometry analysis of high-boiling point components in a liquid, comprising a sample vial heating jacket (1), a sample vial (2), a vacuum pumping pipeline (4) and a sample injection pipeline (7), and a sample vial The heating jacket (1) is wrapped on the outside of the sample bottle (2), and is characterized in that: Two gas outlets are provided on the top of the sealed sample bottle, wherein one gas outlet is connected to the inlet end of a vacuum pipeline switch valve (5) through a vacuum pumping pipeline (4), and the outlet end of the vacuum pipeline switch valve (5) is connected There is a vacuum pump (6); the other gas outlet is connected to the inlet end of a purge gas pipeline switch valve (8) through a purge gas pipeline (7), and the outlet end of the purge gas pipeline switch valve (8) is connected to the mass spectrometer ( 10) The injection port is connected; A sampling pipeline heating jacket (9) is arranged outside the sampling pipeline (7) and the opening and closing valve (8) of the sampling pipeline; A gas inlet is provided on the side wall of the sample bottle (2), and is connected with the outlet end of a purge gas pipeline switch valve (12) through a purge gas pipeline (13), and the purge gas pipeline switch valve (12) has a gas inlet. The inlet end is connected to a purge gas source (11). 2. a kind of sampling device for direct mass spectrometry analysis of high boiling point components in a liquid according to claim 1, is characterized in that: A liquid sample (3) is filled in the sample bottle (2); the gas inlet connected to the purge gas pipeline (13) on the side wall of the sample bottle (2) is arranged above the liquid level of the liquid sample (3). 3. a kind of sampling device for direct mass spectrometry analysis of high boiling point components in a liquid according to claim 1, is characterized in that: The sample bottle heating jacket (1) is composed of a heat insulating material layer coated on the outer wall surface of the sample bottle (2), and an electric heating element located between the outer wall of the sample bottle and the heat insulating material layer; The sample injection pipeline heating jacket (9) is composed of a thermal insulation material layer covering the outer wall of the sample injection pipeline, and an electric heating element located between the outer wall of the sample injection pipeline and the thermal insulation material layer; The insulating material is one or more of glass fiber, asbestos, rock wool, and aerogel felt; The electric heating element is one or more of electric heating wire, electric heating belt and electric heating rod; The heating temperature of the sample bottle heating jacket (1) is room temperature to 500°C, and the heating temperature of the purge gas pipeline (13) is room temperature to 500°C. 4. a kind of sampling device for direct mass spectrometry analysis of high boiling point components in a liquid according to claim 1, is characterized in that: The flow rate of the purging gas flowing out from the purging gas source (11) is 0-1 L/min. 5. a kind of sampling method that adopts the arbitrary described device of claim 1-4 to realize the direct mass spectrometry analysis of high boiling point components in liquid, comprises the following steps: A. Load the liquid sample (3) to be tested into the sample bottle (2); B. Use the sample bottle heating jacket (1) to heat the sample bottle (2) and the liquid sample (3) to room temperature to less than 150°C, and close the on-off valve (8) of the injection line and the on-off valve of the purge gas line (12). ), open the vacuum line switch valve (5) and vacuum pump (6); C. Maintain for 0.1 to 100 minutes, so that the low-boiling volatile components in the liquid sample (3) are fully vaporized and discharged through a vacuum pump; D. Rapidly raise the temperature of the sample bottle heating jacket (1) to 150℃～500℃, close the vacuum line switch valve (5) and vacuum pump (6) at the same time, and open the sampling line switch valve (8) and the purge gas line switch valve (12); E. After the high boiling point components in the liquid sample (3) are vaporized at high temperature, they enter the mass spectrometer ( 10) in the detection.

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