Temperature control purging continuous sampling system combined with gas real-time mass spectrometry technology

Abstract

The invention belongs to the technical field of mass spectrometry, and particularly relates to a temperature-controlled purging continuous sampling system combined with a gas real-time mass spectrometry technology, which adopts temperature-controlled purging equipment to purge organic matters dissolved in liquid, and is combined with a gas real-time mass spectrometer to quickly detect the continuously purged organic matters in real time, and meanwhile, mass spectrometry signal accumulation is carried out, so that the mass spectrometry is realized. The sensitivity of real-time detection of the organic matters in the liquid can be greatly improved; the real-time high-sensitivity analysis of organic matters dissolved in a liquid sample by the gas real-time mass spectrometer is realized by synchronously carrying out continuous purging sampling, real-time mass spectrum detection and mass spectrum signal accumulation.

Description

Technical Field

[0001] The invention belongs to the technical field of mass spectrometry, and in particular relates to a temperature-controlled purge continuous sampling system used in conjunction with a gas real-time mass spectrometry technology. Background Art

[0002] Monitoring of dissolved organic matter in liquids has always been a focus of scientific research, environmental monitoring, and public health. Real-time and rapid detection of dissolved organic matter in liquid samples helps to dynamically assess water quality safety and timely monitor industrial emissions. Liquid chromatography (LC) or liquid chromatography-mass spectrometry (LC-MS) technology is currently the mainstream method for detecting dissolved organic matter in liquid samples. These methods use liquid chromatography columns to separate and detect different organic components in samples, but have the disadvantages of long chromatographic separation time and polarity discrimination of chromatographic columns against different components. If offline chromatography or chromatography-mass spectrometry technology is to detect multiple organic components with different polarities, it is necessary to replace chromatographic columns of different polarity types, so it is not suitable for comprehensive and rapid detection of organic matter in liquid samples.

[0003] The combination of a purge and trap instrument and a gas chromatograph is another mainstream method for detecting dissolved organic matter in liquid samples. This method uses flowing gas to "purge" the organic components in the liquid sample, and then uses a cold trap trap equipped with an adsorbent to adsorb the purged organic matter, and then sends the sample to the gas chromatograph for analysis through thermal desorption. The cold trap enricher in the purge and trap instrument has limitations such as molecular discrimination, memory effect and inability to perform real-time online detection. First, the adsorbent in the cold trap trap is selective for organic molecules with different structures, and the adsorbent needs to be replaced to meet the testing requirements of different target samples. In addition, the enrichment and decomposition temperatures of the cold trap trap are selective for organic molecules with different boiling points, so corresponding enrichment and decomposition temperatures need to be used to specifically analyze the target organic matter. At the same time, the memory effect of the inner wall of the cold trap trap and the adsorbent material limits the detection sensitivity of the instrument. In the traditional purge and trap gas chromatography analysis and testing process, the purge, trapping, analysis and detection steps are performed sequentially, making it impossible to achieve real-time and rapid sample detection; therefore, the above defects limit the application of traditional purge and trap gas chromatography in the rapid and high-sensitivity analysis of dissolved organic matter in liquid samples. Summary of the invention

[0004] The present invention provides a temperature-controlled purge continuous sampling system used in conjunction with gas real-time mass spectrometry technology, which is intended to solve the technical problems of molecular discrimination, memory effect and inability to implement online detection in cold trap enrichment in traditional purge-trap instruments.

[0005] A temperature-controlled purge continuous sampling system used in conjunction with a gas real-time mass spectrometry technique, comprising a temperature-controlled purge device and a gas real-time mass spectrometer; The gas outlet of the temperature-controlled purge device is connected to the gas inlet of the gas real-time mass spectrometer; Based on the continuous sampling of the temperature-controlled purge device, the organic matter dissolved in the liquid is purged and introduced into the gas real-time mass spectrometer, and the mass spectrometer signal is accumulated to perform real-time analysis on the organic matter dissolved in the liquid sample; The temperature-controlled purge equipment, gas real-time mass spectrometer and mass spectrometry signal accumulation are carried out simultaneously.

[0006] In the present invention, continuous purge injection, real-time mass spectrometry detection and mass spectrometry signal accumulation are carried out simultaneously, so that the gas real-time mass spectrometer can perform real-time and high-sensitivity analysis of organic matter dissolved in liquid samples, and effectively solves the technical problems of analytical discrimination, memory effect and inability to detect in real time in cold trap enrichment in traditional purge and trap instruments.

[0007] Furthermore, the temperature-controlled purge device includes a liquid storage chamber, a waste liquid outlet, a liquid sample inlet, a purge gas inlet, a temperature control module, and the gas outlet; The liquid storage chamber is used to store the input liquid sample; The waste liquid discharge port is used to discharge the waste liquid after detection in the liquid storage chamber; The liquid sample introduction port is used to input the liquid sample into the liquid storage chamber; The purge gas inlet is used to introduce liquid sample purge gas and act on the liquid sample stored in the liquid storage cavity; The temperature control module is used to adjust the temperature inside the temperature control purge equipment.

[0008] Furthermore, the purge gas flow rate of the temperature-controlled purge equipment is 5 to 1000 sccm.

[0009] Furthermore, the temperature of the temperature-controlled purging equipment is from room temperature to 500°C.

[0010] Furthermore, the cumulative number of mass spectra of the gas real-time mass spectrometer is 1.00E3 to 1.00E7 times.

[0011] Furthermore, the mass spectrum detection time of the gas mass spectrometer is 30 to 500 μs.

[0012] The beneficial effects of the present invention include: In the present invention, continuous purge injection, real-time mass spectrometry detection and mass spectrometry signal accumulation are carried out simultaneously, so that the gas real-time mass spectrometer can perform real-time and high-sensitivity analysis of organic matter dissolved in liquid samples, and effectively solves the technical problems of analytical discrimination, memory effect and inability to detect in real time in cold trap enrichment in traditional purge and trap instruments. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 A diagram showing the working principle of the system provided in an embodiment of the present invention.

[0014] Figure 2 A schematic diagram of a temperature-controlled purge device provided in an embodiment of the present invention.

[0015] Figure 3 A comparison chart of the change of signal intensity with purge time in the cold trap capture and mass spectrometry signal accumulation experiment provided in the embodiment of the present invention, wherein Figure 3 Part A in the middle is a graph showing the signal intensity variation of 2-methylisoborneol with the detection time; Figure 3 Part B in the middle is a graph showing the change in signal intensity of geosmin over detection time.

[0016] Explanation of reference numerals: 1. Gas outlet; 2. Gas inlet; 3. Liquid storage chamber; 4. Liquid sample inlet; 5. Temperature control module; 6. Waste liquid outlet; 7. Purge gas inlet. DETAILED DESCRIPTION

[0017] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application usually described and shown in the drawings here can be arranged and designed in various configurations. 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 application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0018] like Figure 1 As shown, a temperature-controlled purge continuous sampling system used in conjunction with a gas real-time mass spectrometry technique comprises a temperature-controlled purge device and a gas real-time mass spectrometer; The gas outlet 1 of the temperature-controlled purge device is connected to the gas inlet 2 of the gas real-time mass spectrometer; Based on the continuous sampling of the temperature-controlled purge device, the organic matter dissolved in the liquid is purged and introduced into the gas real-time mass spectrometer, and the mass spectrometer signal is accumulated to perform real-time analysis on the organic matter dissolved in the liquid sample; The temperature-controlled purge equipment, gas real-time mass spectrometer and mass spectrometry signal accumulation are carried out simultaneously.

[0019] See also Figure 2 As shown, the temperature-controlled purge device includes a liquid storage chamber 3, a waste liquid outlet 6, a liquid sample inlet 4, a purge gas inlet 7, a temperature control module 5 and the gas outlet 1; The liquid storage chamber 3 is used to store the input liquid sample; The waste liquid discharge port 6 is used to discharge the waste liquid after detection in the liquid storage chamber 3; The liquid sample introduction port 4 is used to input the liquid sample into the liquid storage chamber 3; The purge gas inlet 7 is used to introduce liquid sample purge gas and act on the liquid sample stored in the liquid storage chamber 3; The temperature control module 5 is used to adjust the temperature inside the temperature control purge device.

[0020] The purge gas flow rate of the temperature-controlled purge device is 5 to 1000 sccm.

[0021] The temperature of the temperature-controlled purging equipment is from room temperature to 500°C.

[0022] In this embodiment, the settings of the purge gas flow rate and temperature of the temperature-controlled purge device are optimized according to the type of the test sample, wherein the optimization can be performed through experiments or based on the physical properties of the test sample.

[0023] The mass spectrum of the gas real-time mass spectrometer is accumulated 1.00E3 to 1.00E7 times; since in this embodiment, mass spectrum data is output once every 30 to 500 μs, all data points collected in 30 to 500 μs are accumulated and averaged to output a mass spectrum signal graph; The mass spectrum detection time of the gas real-time mass spectrometer is 30 to 500 μs; In this embodiment, the time for producing a mass spectrum is 30 to 500 μs. In a time-of-flight mass spectrometer, the time it takes for different ions to arrive at the detector is determined by the time it takes for ions with small mass numbers to arrive at the detector. Ions with large mass numbers take the shortest time to arrive at the detector, while ions with large mass numbers take a long time to arrive at the detector. Therefore, if larger mass ions need to be detected, the time for producing the spectrum needs to be extended accordingly.

[0024] In this embodiment, the real-time continuous detection of dissolved organic matter in the liquid can be achieved by combining the temperature-controlled purge device and the gas real-time mass spectrometer, and the combination of the temperature-controlled purge device and the gas real-time mass spectrometer described in this embodiment can be applied to on-site installation to achieve real-time online detection. The description of real-time online detection is as follows: The liquid sample introduction port 4 of the temperature-controlled purge device is placed in a liquid (e.g., a flow basin), and the liquid sample can be pumped into the liquid storage chamber 3 for temperature-controlled purge by pumping. Through the gas introduction port 1 and the gas introduction port 2 of the gas real-time mass spectrometer, the gas enters the gas real-time mass spectrometer for real-time detection, thereby achieving real-time online detection. It should be noted that, in this embodiment, the equipment used includes the temperature-controlled purge device and the gas real-time mass spectrometer, while in the prior art, in addition to the purge trap and the gas chromatograph, an adsorbent cooler is also required. The trap collector adsorbs the purged organic matter, and then sends the sample to the gas chromatograph for analysis after pyrolysis; it can be seen that the prior art procedures are cumbersome and cannot achieve real-time online detection. The reason is that the adsorbent in the cold trap collector is selective for organic molecules with different structures, and the adsorbent needs to be replaced to meet the testing requirements of different target samples; therefore, based on the prior art and the technical solution of the present application, it can be seen that the structure and process of the present application are less than those of the prior art, and the beneficial effects obtained are also unattainable by the prior art, namely, real-time and continuous online detection.

[0025] Moreover, the technical solution adopted in this embodiment is significantly higher than the existing technology in terms of the signal strength detected by the existing technology. Figure 3 And the following tests: At present, there are two types of mass spectrometers dedicated to online rapid detection of gases: ultraviolet photoionization-time of flight mass spectrometry and proton transfer reaction-time of flight mass spectrometry. This experiment uses a proton transfer reaction-time of flight mass spectrometer for the experiment, as follows: The experimental test sample was a 1 μg / L standard mixed solution of 2-methylisoborneol and geosmin; in the cold trap capture experiment, the temperature-controlled purge bottle was connected to the cold trap concentrator, and the purge and capture were performed for 60, 120, 180, 240, 300, 360, 420, 480, 540, and 600 s in sequence, and then the samples were analyzed and released into the gas real-time mass spectrometer for detection. In the mass spectrometry signal accumulation experiment, the temperature-controlled purge bottle was directly connected to the gas real-time mass spectrometer, and the gradient was purged and detected online for 60, 120, 180, 240, 300, 360, 420, 480, 540, and 600 s in sequence, and the mass spectra were collected in real time and accumulated synchronously; in the cold trap capture and mass spectrometry signal accumulation experiments, the signal intensity was compared with the purge time, as shown in the figure. Figure 3 As shown; the change of the signal intensity gain multiple of the mass spectrum cumulative signal relative to the cold trap capture with the purge time is shown in Table 1; Table 1 Changes in the signal intensity gain of the mass spectrometer cumulative signal relative to the cold trap capture signal as a function of the purge time

[0026] It can be seen from the experiment that the temperature-controlled purge continuous sampling system is used in conjunction with the gas real-time mass spectrometry technology. Through the simultaneous continuous purge sampling, real-time mass spectrometry detection and mass spectrometry signal accumulation, the mass spectrometry cumulative signal obtained is significantly stronger than the signal after cold trap enrichment. In addition, the shorter the purge time, the higher the gain multiple of the mass spectrometry cumulative signal compared to the cold trap capture signal, which further proves the real-time monitoring capability of this patented technology for dissolved organic matter in liquids.

[0027] In summary, the patent of the present invention can be applied to the real-time, rapid and highly sensitive detection of organic matter in liquid samples such as drinking water, surface water, biological fluids and liquid materials. It has good application prospects and can realize online real-time rapid detection, eliminating the technical problems of molecular discrimination, memory effect and inability to detect in real time online in cold trap enrichment in traditional purge and trap instruments.

[0028] The above embodiments only express the specific implementation methods of the present application, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the present application. For ordinary technicians in this field, several modifications and improvements made without departing from the concept of the present application all belong to the protection scope of the present application.

Claims

1. A temperature-controlled purge continuous sampling system used in conjunction with gas real-time mass spectrometry, characterized in that: Includes temperature-controlled purge equipment and gas real-time mass spectrometer; The gas outlet of the temperature-controlled purge device is connected to the gas inlet of the gas real-time mass spectrometer; Based on the continuous sampling of the temperature-controlled purge device, the organic matter dissolved in the liquid is purged and introduced into the gas real-time mass spectrometer, and the mass spectrometer signal is accumulated to perform real-time analysis on the organic matter dissolved in the liquid sample; The temperature-controlled purge equipment, gas real-time mass spectrometer and mass spectrometry signal accumulation are carried out simultaneously.

2. The temperature-controlled purge continuous sampling system used in conjunction with gas real-time mass spectrometry according to claim 1, characterized in that: The temperature-controlled purge device comprises a liquid storage chamber, a waste liquid discharge port, a liquid sample introduction port, a purge gas introduction port, a temperature control module and the gas introduction port; The liquid storage chamber is used to store the input liquid sample; The waste liquid discharge port is used to discharge the waste liquid after detection in the liquid storage chamber; The liquid sample introduction port is used to input the liquid sample into the liquid storage chamber; The purge gas inlet is used to introduce liquid sample purge gas and act on the liquid sample stored in the liquid storage cavity; The temperature control module is used to adjust the temperature inside the temperature control purge equipment.

3. The temperature-controlled purge continuous sampling system used in conjunction with gas real-time mass spectrometry according to claim 1, characterized in that: The purge gas flow rate of the temperature-controlled purge device is 5 to 1000 sccm.

4. The temperature-controlled purge continuous sampling system used in conjunction with gas real-time mass spectrometry according to claim 1, characterized in that: The temperature of the temperature-controlled purging equipment is from room temperature to 500°C.

5. The temperature-controlled purge continuous sampling system used in conjunction with gas real-time mass spectrometry according to claim 1, characterized in that: The cumulative number of mass spectra of the gas real-time mass spectrometer is 1.00E3 to 1.00E7 times.

6. The temperature-controlled purge continuous sampling system used in conjunction with gas real-time mass spectrometry according to claim 1, characterized in that: The mass spectrum detection time of the gas real-time mass spectrometer is 30 to 500 μs.

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