Real-time monitoring pollutant degradation analysis system and application thereof in antibiotic pollutant analysis

Abstract

The invention belongs to the technical field of mass spectrometry, and particularly relates to a real-time monitoring pollutant degradation analysis system which comprises a photocatalysis device unit, a direct-current high-voltage device unit, a three-layer capillary tube and a mass spectrometry detection unit which are connected in sequence, the three layers of capillary tubes comprise an outer-layer capillary tube, a middle capillary tube and an inner-layer capillary tube; the photocatalysis device unit adopts a degradation pool for degrading antibiotic pollutants through photocatalysis under illumination, and is connected with the direct-current high-voltage device unit through a guide pipe; one end of the direct-current high-voltage device unit is connected with the photocatalysis device unit, the other end of the direct-current high-voltage device unit is connected with the three-layer capillary tube, and the direct-current high-voltage device unit is further connected with a high-voltage power supply, sheath gas and sheath liquid. According to the invention, high-sensitivity analysis of real-time on-line detection of the degradation process of environmental pollutants can be realized.

Description

Technical Field

[0001] The invention belongs to the technical field of mass spectrometry analysis, and in particular relates to a real-time monitoring pollutant degradation analysis system and an application thereof in antibiotic pollutant analysis. Background Art

[0002] Roxithromycin is a semisynthetic macrolide antibiotic with a chemical name of 9E-[O-[(2-methoxyethoxy)-methyloxime]erythromycin and a molecular formula of C 41 H 76 N2O 15 Roxithromycin is widely present in the aquatic environment. Roxithromycin and its metabolites can accumulate in aquatic animals, causing biochemical dysfunction in aquatic animals, posing risks to aquatic and terrestrial ecosystems, and further endangering human health.

[0003] Real-time online technology mainly combines a photocatalytic degradation device with a label-free high-resolution mass spectrometer to monitor the degradation process of antibiotic pollutants in real time, providing an analytical method for rapid and sensitive detection of the degradation process of roxithromycin. This technology can realize continuous online monitoring of pollutant degradation. This real-time monitoring overcomes the time lag problem of traditional manual sampling and analysis methods, and avoids phenomena such as data discontinuity and incompleteness during the monitoring process. Summary of the invention

[0004] The purpose of the present invention is to provide a real-time monitoring pollutant degradation analysis system and its application in antibiotic pollutant analysis, which can realize high-sensitivity analysis of real-time online detection of environmental pollutant degradation process. The degradation liquid in the degradation pool is introduced into the three-layer capillary through a peristaltic pump. The degradation liquid is transmitted in the capillary and forms charged droplets. The sheath gas and sheath liquid are assisted to enable the charged droplets to obtain better ionization efficiency. With the addition of a DC high-voltage power supply, the charged droplets enter the mass spectrometry detection unit for mass spectrometry detection and analysis.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A real-time monitoring and analysis system for pollutant degradation comprises a photocatalytic device unit, a direct current high voltage device unit, a three-layer capillary and a mass spectrometry detection unit connected in sequence; the three-layer capillary is divided into an outer capillary, a middle capillary and an inner capillary;

[0007] The photocatalytic device unit uses a degradation pool for photocatalytically degrading antibiotic pollutants under light, and is connected to the direct current high voltage device unit through a conduit;

[0008] One end of the DC high-voltage device unit is connected to the photocatalytic device unit, the other end of the DC high-voltage device unit is connected to the three-layer capillary, and the DC high-voltage device unit is also connected to a high-voltage power supply, sheath gas and sheath liquid;

[0009] One end of the three-layer capillary is connected to a direct current high voltage device unit, the other end of the three-layer capillary is a mass spectrometry electrospray needle, and one end of the mass spectrometry electrospray needle is connected to a mass spectrometry detection unit.

[0010] The light intensity of the photocatalytic device unit is 6.379 mW / cm 2 .

[0011] The photocatalytic device unit further comprises a peristaltic pump, and the flow rate of the peristaltic pump is 1-10 μL / min.

[0012] The distance between the mass spectrometer electrospray needle and the entrance of the mass spectrometer detection unit is 5-20 mm.

[0013] The inner diameter of the inner capillary of the three-layer capillary is 30-60 μm, the inner diameter of the middle capillary is 200-300 μm, and the inner diameter of the outer capillary is 500-600 μm.

[0014] The lengths of the three layers of capillaries are all 10-100 cm.

[0015] The high voltage power supply is a DC high voltage power supply with a voltage value of ±1-5kV.

[0016] The three-layer capillary is located at one end of the mass spectrometer electrospray needle, the outlet end of the middle capillary is 5 mm longer than the inner capillary, the sheath gas pipeline is between the outer capillary and the middle capillary, and the outer capillary is 1 mm shorter than the middle capillary for loading nitrogen.

[0017] Preferably, the sheath liquid is volatile solvent methanol, and the sheath gas is nitrogen.

[0018] The application of a real-time monitoring pollutant degradation analysis system in the real-time monitoring and analysis of the degradation process of roxithromycin antibiotic pollutants comprises the following steps:

[0019] At a light intensity of 6.379 mW / cm 2 Under irradiation, 1 mg / L roxithromycin antibiotic was photocatalytically degraded in a pure water medium in a photodegradation device unit for 40 minutes, and the pollutants in the degradation tank and their degradation liquid were introduced into the three-layer capillary through a catheter via a peristaltic pump. Sheath liquid (methanol) and sheath gas (nitrogen) were added to the three-layer capillary, and through a mass spectrometer electrospray needle and a DC high-voltage power supply, they entered the mass spectrometer detection unit for real-time monitoring of the degradation process and analysis.

[0020] Preferably, the antibiotic comprises one of tetracyclines, macrolides, penicillins and quinolones.

[0021] More preferably, the antibiotic contaminant includes at least one of roxithromycin, lincomycin, clarithromycin, norfloxacin and moxifloxacin. The antibiotic contaminant is preferably roxithromycin.

[0022] The technical effects achieved by the present invention are:

[0023] The present invention discloses a real-time monitoring pollutant degradation analysis system and its application in antibiotic pollutant analysis. The photocatalytic degradation device is combined with high-resolution atmospheric pressure mass spectrometry detection to monitor the degradation of antibiotic pollutants in real time, providing an analysis method for rapid and sensitive monitoring of the degradation process of roxithromycin. The method is simple to operate, does not require complicated sample pretreatment and chromatographic separation processes, has a fast analysis speed, high sensitivity, and can fully realize online analysis and real-time monitoring of the pollutant degradation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of a high-resolution atmospheric pressure mass spectrometer online detection device according to an embodiment of the present invention;

[0025] Figure 2 This is a structural diagram of a high-resolution atmospheric pressure mass spectrometry online detection device according to an embodiment of the present invention;

[0026] Figure 3 It is an ion current diagram extracted by online detection of roxithromycin degradation by a real-time monitoring pollutant degradation analysis system according to an embodiment of the present invention;

[0027] Figure 4 This is a positive ion mode diagram of online detection of the real-time monitoring pollutant degradation analysis system according to an embodiment of the present invention;

[0028] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0029] 1. Illumination device; 2. Degradation cell; 3. Pollutant degradation liquid channel; 4. Methanol; 5. DC high voltage device; 6. Sheath liquid channel; 7. Nitrogen; 8. Sheath gas channel; 9. High-resolution mass spectrometer. DETAILED DESCRIPTION

[0030] In order to make the purpose and advantages of the present invention more clearly understood, the present invention is specifically described below in conjunction with embodiments. It should be understood that the following text is only used to describe one or several specific embodiments of the present invention, and does not strictly limit the scope of protection of the specific claims of the present invention.

[0031] Embodiment 1:

[0032] like Figure 1-Figure 2As shown, a real-time monitoring pollutant degradation analysis system comprises a photocatalytic device unit 1, 2, a DC high voltage device unit 5, a three-layer capillary 3, 7, 8 and a mass spectrometry detection unit 9 connected in sequence; the three-layer capillary is divided into an outer capillary, an intermediate capillary and an inner capillary, which correspond to a pollutant degradation liquid channel 3, a sheath liquid channel 6 and a sheath gas channel 8 respectively;

[0033] The photocatalytic device unit is under the illumination device 1, and uses the degradation tank 2 for photocatalytic degradation of antibiotic pollutants, and is connected to the direct current high voltage device unit 5 through the conduit of the pollutant degradation liquid channel 3;

[0034] One end of the DC high voltage device unit 5 is connected to the photocatalytic device unit 2, and the other end of the DC high voltage device unit 5 is connected to a three-layer capillary, which is composed of a pollutant degradation liquid channel 3, a sheath liquid channel 6 and a sheath gas channel 8. The DC high voltage device unit 5 is also connected to a sheath liquid 6 and a sheath gas 8, wherein the sheath liquid is methanol 4 and the sheath gas is nitrogen 7;

[0035] One end of the three-layer capillary is connected to the direct current high voltage device unit 5 , and the other end of the three-layer capillary is a mass spectrometer electrospray needle, and one end of the mass spectrometer electrospray needle is connected to the high-resolution mass spectrometer unit 9 .

[0036] like Figure 2 As shown, in the illumination device 1, the pollutants are degraded in the photodegradation pool 2, and the pollutant degradation liquid channel 3 is introduced by a precision peristaltic pump. The DC high-voltage device unit 5 is a conductive metal component. The DC high-voltage device unit 5 is connected to the three-layer capillary as the pollutant degradation liquid input pipeline. The distribution and analysis speed of the degradation in the pipeline are controlled by the flow rate. The high-voltage power supply applies a DC high-voltage electric field by connecting the DC high-voltage device unit to charge the droplets flowing through. The sheath liquid 6 is connected to the DC high-voltage device unit 5 and enters the middle capillary through the DC high-voltage device unit 5. The degradation liquid can be focused and separated by the surrounding sheath liquid 6 and flow to the outlet along the axis. Under the action of the high-voltage electric field 5, these substances form charged droplets. The sheath gas 8 pipeline is connected to the DC high-voltage device unit 5 and enters the outer capillary through the DC high-voltage device unit 5, which is used to load nitrogen 7 to assist the solvent evaporation of the charged droplets to obtain better power efficiency. The other end of the three-layer capillary is used as a mass spectrometer electrospray needle. The degradation liquid enters the inner capillary for transmission and forms charged droplets, which enter the mass spectrometry detection unit 9 for detection and analysis.

[0037] The light intensity of the photocatalytic device unit is 6.379mW / cm 2 .

[0038] The photocatalytic device unit also includes a peristaltic pump, and the flow rate of the peristaltic pump is 1-10 μL / min.

[0039] The distance between the mass spectrometer electrospray needle and the entrance of the mass spectrometer detection unit is 5-20 mm.

[0040] The inner diameter of the inner capillary of the three-layer capillary is 30-60 μm, the inner diameter of the middle capillary is 200-300 μm, and the inner diameter of the outer capillary is 500-600 μm.

[0041] The lengths of the three layers of capillaries are all 10-100 cm.

[0042] The high voltage power supply is a DC high voltage power supply with a voltage value of ±1-5kV.

[0043] In this embodiment, the analysis system is composed of a photocatalytic device unit, a DC high voltage device unit, a three-layer capillary and a mass spectrometry detection unit. Figure 1 As shown; the flow rate of the peristaltic pump is 3μL / min, the inlet distance between the mass spectrometer electrospray needle and the mass spectrometer detection unit is 10mm, the inner diameter of the inner capillary of the three-layer capillary is 50μm, the outer diameter is 220μm, the inner diameter of the middle capillary is 250μm, the outer diameter is 363μm, and the inner diameter of the outer capillary is 530μm, the outer diameter is 680μm, the sheath liquid flow rate is 15μL / min, the sheath gas is 0.5MPa, the high voltage power supply is a DC high voltage power supply, and the voltage value is +3kV.

[0044] The three-layer capillary is located at one end of the mass spectrometer electrospray needle. The outlet end of the middle capillary is 5 mm longer than that of the inner capillary. The degradation liquid can be focused and separated by the surrounding sheath liquid and flow to the outlet along the axis. Under the action of the high-voltage electric field, these substances form charged droplets. There is a sheath gas pipeline between the outer capillary and the middle capillary, and the outer capillary is 1 mm shorter than the middle capillary. It is used to load nitrogen to assist the solvent evaporation of the charged droplets to obtain better power efficiency.

[0045] Embodiment 2:

[0046] The application of a real-time monitoring pollutant degradation analysis system in the real-time monitoring and analysis of the degradation process of roxithromycin antibiotic pollutants comprises the following steps:

[0047] Solution preparation:

[0048] Accurately weigh 10 mg of roxithromycin standard on an analytical balance and place the weighed roxithromycin in a 10 mL light-proof volumetric flask; dissolve the roxithromycin in an appropriate amount of methanol, first add a small amount of solvent, shake thoroughly to completely dissolve the roxithromycin, and make up to 10 mL to obtain 1 mg / mL roxithromycin.

[0049] Use a pipette to accurately draw 50 μL of 1 mg / mL roxithromycin solution, transfer the drawn solution to a 50 mL volumetric flask, make up to 50 mL with ultrapure water, and mix thoroughly to obtain 50 mL of 1 mg / L roxithromycin aqueous solution.

[0050] 50mL of 1mg / L roxithromycin was added into the photocatalytic degradation cell. 2 Under irradiation, 1 mg / L roxithromycin (m / z 837.53) antibiotic was photocatalytically degraded in a pure water medium in a photodegradation device unit for 40 min, and the pollutants in the degradation tank and their degradation liquid were introduced into the three-layer capillary through a catheter via a peristaltic pump. Sheath liquid (methanol) and sheath gas (nitrogen) were added to the three-layer capillary, and through a mass spectrometer electrospray needle and a DC high-voltage power supply, the detection mode was positive ion mode, so that it entered the mass spectrometer detection unit for real-time monitoring of the degradation process and analysis.

[0051] In order to study the dynamic changes of the degradation process of the above antibiotic Roxithromycin, a technique of real-time online monitoring of the degradation process by open mass spectrometry at normal pressure was adopted. In this embodiment, the degradation changes of Roxithromycin were monitored so as to observe and analyze the degradation rate of Roxithromycin in real time.

[0052] Embodiment 3:

[0053] Based on Example 2, the parameter conditions of the degradation device are optimized:

[0054] (1) Optimize gas flow rate

[0055] This study uses nitrogen as the sheath gas, which can promote the ionization of charged spray, and compares the effects of different sheath gas sizes on pollutant degradation analysis. The results show that when the nitrogen content is too small, the charged droplets are not completely ionized, resulting in a weak target signal intensity. As the intensity of the carrier gas increases, the total ion intensity and the target ion intensity also increase. When the nitrogen size is 0.5MPa, the signal intensity of the mass spectrometer monitoring the degradation liquid is the strongest. When the carrier gas intensity is greater than 0.5MPa, the target ion intensity will weaken because too high a carrier gas will blow away the charged droplets, making it difficult for the charged ions to enter the mass spectrometer detection. Therefore, 0.5MPa was selected as the optimal sheath gas intensity for subsequent experiments.

[0056] (2) Optimization of sheath fluid flow rate

[0057] The sheath liquid flow rate is one of the important factors affecting the signal of the degradation solution. By changing the flow rate of the peristaltic pump and the sheath liquid, the ions entering the detection system are more balanced for detection; if the sheath liquid flow rate is too large, the sample will be over-diluted, which will reduce the signal of the degradation solution; if the sheath liquid flow rate is too small, the degradation solution cannot be completely ionized during real-time online monitoring, and a stable signal cannot be generated. When the sheath liquid flow rate is set to 15μL / min, the device can generate a stable signal and detect a strong target ion signal. When the sheath liquid flow rate increases, the target pollutant signal detected per unit time decreases, and the target substance will be over-diluted, resulting in a decrease in signal intensity. When the sheath liquid flow rate is 10-15μL / min, as the sheath liquid flow rate decreases, the mass spectrometry signal also decreases. Therefore, after optimization, 15μL / min was selected as the optimal sheath liquid flow rate for subsequent experiments.

[0058] (3) DC voltage optimization

[0059] The magnitude of the applied high voltage determines the ionization efficiency of the target substance to be analyzed. The lower the applied voltage, the lower the ionization efficiency of the sample to be detected, or even no ionization occurs, which will seriously affect the response intensity and sensitivity of the target. On the contrary, the higher the applied voltage, the higher the ionization efficiency will be. However, if the voltage exceeds a certain range, it is easy to cause discharge at the capillary tip. Excessive voltage will have a certain impact on the signal-to-noise ratio, which is not conducive to the analysis and determination of the degradation solution. The study compared the effects of different high-voltage electric fields (including 0, 0.5, 1, 1.5, 2.0, 2.5, 3.0, 3.5, and 4.0 kV) on the intensity of the target ions. The results showed that when the voltage was low, the mass spectrometry signal intensity was weak and unstable, and a hanging drop phenomenon would also appear at the capillary outlet. With the increase of the high-voltage electric field, the intensity of the mass spectrometry signal gradually increased with the increase of the voltage. When the applied voltage was +3 kV, the mass spectrometry signal intensity was the highest. When the applied high-voltage electric field was greater than 3 kV, the mass spectrometry signal weakened. Therefore, 3 kV was selected as the optimal applied voltage for subsequent experiments.

[0060] Embodiment 4:

[0061] Based on Examples 1-3, this example discloses the degradation performance of roxithromycin under different illumination times:

[0062] In order to further explore the degradation efficiency of roxithromycin at different times, four main degradation times were selected for recording. Through mass spectrometry analysis, it can be found that with the passage of time, the degradation liquid has undergone obvious changes. The degradation rates of pollutants were taken at illumination times of 0min, 10min, 25min and 40min respectively.

[0063] The following experimental parameters were used for the experiment: the flow rate of the peristaltic pump was 3 μL / min; the sheath liquid flow rate was 15 μL / min, the sheath gas was 0.5 MPa, the DC high voltage value was 3 kV, the detection mode was positive ion mode; the photocatalytic device was set at a light intensity of 6.379 mW / cm 2 Irradiation sample photodegradation cell, irradiation time 0min, degradation rate of roxithromycin is 0%

[0064] The following experimental parameters were used for the experiment: the flow rate of the peristaltic pump was 3 μL / min; the sheath liquid flow rate was 15 μL / min, the sheath gas was 0.5 MPa, the DC high voltage value was 3 kV, the detection mode was positive ion mode; the photocatalytic device was set at a light intensity of 6.379 mW / cm 2 The sample was irradiated in the photodegradation cell for 10 min, and the degradation rate of roxithromycin was 83.41%.

[0065] The following experimental parameters were used for the experiment: the flow rate of the peristaltic pump was 3 μL / min; the sheath liquid flow rate was 15 μL / min, the sheath gas was 0.5 MPa, the DC high voltage value was 3 kV, the detection mode was positive ion mode; the photocatalytic device was set at a light intensity of 6.379 mW / cm 2 The sample was irradiated in a photodegradation cell for 25 min, and the degradation rate of roxithromycin was 95.98%.

[0066] The following experimental parameters were used for the experiment: the flow rate of the peristaltic pump was 3 μL / min; the sheath liquid flow rate was 15 μL / min, the sheath gas was 0.5 MPa, the DC high voltage value was 3 kV, the detection mode was positive ion mode; the photocatalytic device was set at a light intensity of 6.379 mW / cm 2 The sample was irradiated in a photodegradation cell for 40 minutes, and the degradation rate of roxithromycin was 98.36%.

[0067] Experimental Results

[0068] Depend on Figure 3 It is known that the signal of roxithromycin was measured at m / z 837.5315 in the positive ion mode, with a response value of 10 6 Under the condition of illumination time of 0-15min, the degradation trend of roxithromycin was obvious, and after 15min, its degradation tended to be slow.

[0069] Depend on Figure 4 It is known that roxithromycin was detected at m / z 837.5328 in positive ion mode.

[0070] The above is only a preferred embodiment of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principles of the present invention, and these improvements and modifications should also be considered as the protection scope of the present invention. The structures, devices and operating methods not specifically described and explained in the present invention shall be implemented according to the conventional means in the art unless otherwise specified and limited.

Claims

1. A real-time monitoring and analysis system for pollutant degradation, characterized in that: It comprises a photocatalytic device unit, a direct current high voltage device unit, a three-layer capillary and a mass spectrometry detection unit which are connected in sequence; the three-layer capillary is divided into an outer capillary, a middle capillary and an inner capillary; The photocatalytic device unit uses a degradation pool for photocatalytically degrading antibiotic pollutants under light, and is connected to the direct current high voltage device unit through a conduit; One end of the DC high-voltage device unit is connected to the photocatalytic device unit, the other end of the DC high-voltage device unit is connected to the three-layer capillary, and the DC high-voltage device unit is also connected to a high-voltage power supply, sheath gas and sheath liquid; One end of the three-layer capillary is connected to a direct current high voltage device unit, the other end of the three-layer capillary is a mass spectrometry electrospray needle, and one end of the mass spectrometry electrospray needle is connected to a mass spectrometry detection unit.

2. A real-time monitoring and analysis system for pollutant degradation according to claim 1, characterized in that: The light intensity of the photocatalytic device unit is 6.379 mW / cm 2 .

3. A real-time monitoring and analysis system for pollutant degradation according to claim 1, characterized in that: The photocatalytic device unit further comprises a peristaltic pump, and the flow rate of the peristaltic pump is 1-10 μL / min.

4. A real-time monitoring and analysis system for pollutant degradation according to claim 1, characterized in that: The distance between the mass spectrometer electrospray needle and the entrance of the mass spectrometer detection unit is 5-20 mm.

5. A real-time monitoring and analysis system for pollutant degradation according to claim 1, characterized in that: The inner diameter of the inner capillary of the three-layer capillary is 30-60 μm, the inner diameter of the middle capillary is 200-300 μm, and the inner diameter of the outer capillary is 500-600 μm.

6. A real-time monitoring and analysis system for pollutant degradation according to claim 1, characterized in that: The lengths of the three layers of capillaries are all 10-100 cm.

7. A real-time monitoring and analysis system for pollutant degradation according to claim 1, characterized in that: The high voltage power supply is a DC high voltage power supply with a voltage value of ±1-5kV.

8. A real-time monitoring and analysis system for pollutant degradation according to claim 1, characterized in that: The three-layer capillary is located at one end of the mass spectrometer electrospray needle, the outlet end of the middle capillary is 5 mm longer than the inner capillary, the sheath gas pipeline is between the outer capillary and the middle capillary, and the outer capillary is 1 mm shorter than the middle capillary for loading nitrogen.

9. Application of a real-time monitoring pollutant degradation analysis system according to any one of claims 1 to 8 in real-time monitoring and analysis of the degradation process of roxithromycin antibiotic pollutants.

Images