Online detection device and method for volatile organic compounds in leather

Abstract

The invention discloses an on-line detection device for volatile organic compounds in leather, which comprises a volatile organic compound trap, a microtube plasma generator and a mass spectrometer (9), the volatile organic compound trap comprises a container (1) with an opening and a sealing plug fixed at the opening, one end of a first gas pipeline (13) is connected with a helium source (2), and the other end of the first gas pipeline (13) is connected with a second gas pipeline (13). One end of a second gas pipeline (14) is connected with the microtube plasma generator, the other end of the second gas pipeline (14) penetrates through the sealing plug to be connected with the bottom space in the container (1), one end of the second gas pipeline (14) is connected with the microtube plasma generator, and the other end of the second gas pipeline (14) penetrates through the sealing plug to be connected with the upper space in the container (1). The invention also discloses an online detection method for volatile organic compounds in leather. According to the device disclosed by the invention, a tedious and complicated sample pretreatment step in a conventional detection method can be omitted, online detection of the volatile organic compounds in the leather sample at different environment temperatures is realized, the detection efficiency is greatly improved, and the solvent consumption is reduced.

Description

Technical Field

[0001] The present invention relates to the field of chemical substance detection, and in particular to an on-line detection device and method for volatile organic compounds in leather. Background Art

[0002] Traditional methods for extracting volatile organic compounds from leather often face challenges such as cumbersome pretreatment steps, high organic solvent consumption, and low extraction efficiency. Furthermore, due to the complexity of the leather matrix, target compounds are susceptible to interference, making identification difficult during subsequent chromatographic or mass spectrometric analysis. Furthermore, existing technologies mostly rely on offline laboratory testing, making it difficult to achieve real-time monitoring and rapid feedback during the production process. Summary of the Invention

[0003] The technical problem to be solved by the present invention is: mainly targeting the detection problem of volatile organic compounds in leather products, providing an online detection device for volatile organic compounds in leather with a simple structure, low cost and easy operation, as well as an efficient and accurate online detection method.

[0004] The device consists of four parts: a volatile organic compound (VOC) collector, a heating device, a temperature measuring device, and a microtube plasma generator. A leather sample is placed in the sealed collector. Under heating conditions, organic compounds volatilized from the leather enter the microtube plasma generator under the action of helium gas, where they are ionized into charged ions that are then detected by a mass spectrometer. The temperature of the leather's surroundings is measured in real time by the temperature measuring device, enabling online detection of VOCs in the leather at different temperatures.

[0005] An online detection device for volatile organic compounds in leather comprises a volatile organic compound collector, a microtube plasma generator, and a mass spectrometer. The volatile organic compound collector comprises a container having an opening and a sealing plug disposed at the opening. One end of a first gas pipeline is connected to a helium source, and the other end passes through the sealing plug and is connected to the bottom space inside the container. One end of a second gas pipeline is connected to the microtube plasma generator, and the other end passes through the sealing plug and is connected to the upper space inside the container.

[0006] The microtube plasma generator includes a T-shaped tee, which includes a horizontal pipeline and a vertical pipeline that are interconnected. One end of the horizontal pipeline is connected to the second gas pipeline, and a fused silica capillary is arranged inside the other end. One end of the fused silica capillary is arranged inside the horizontal pipeline, and the other end passes through the horizontal pipeline and is close to the mass spectrometer.

[0007] The online detection device for volatile organic compounds in leather described in the present invention further includes a tungsten wire, one end of which is arranged inside the fused silica capillary, and the other end of which passes through the vertical pipeline of the T-shaped tee and is connected to a high-frequency and high-voltage AC power supply.

[0008] The online detection device for volatile organic compounds in leather described in the present invention further includes a flexible sleeve, which is sleeved on the fused silica capillary; the flexible sleeve, the fused silica capillary, the horizontal pipeline of the T-shaped tee and the inlet of the mass spectrometer are coaxially arranged horizontally; and the three interfaces of the T-shaped tee are all sealed with threaded plugs.

[0009] In the on-line detection device for volatile organic compounds in leather of the present invention, the leather sample is arranged at the bottom of the container.

[0010] The online detection device for volatile organic compounds in leather described in the present invention further includes a temperature measuring device consisting of a thermocouple and a temperature display. The thermocouple is arranged inside the container near the leather sample, one end of the wire is connected to the thermocouple, and the other end passes through the sealing plug and is connected to the temperature display outside the container.

[0011] The online detection device for volatile organic compounds in leather of the present invention further comprises a desktop infrared heating lamp with adjustable power and angle for irradiating and heating the container during testing.

[0012] The online detection device for volatile organic compounds in leather described in the present invention comprises: the container is a glass conical flask, the helium source is a high-purity helium cylinder, a gas flow controller is provided on the first gas pipeline, and the sealing plug is a perforated rubber plug; the first gas pipeline and the second gas pipeline are polytetrafluoroethylene hoses with an outer diameter of 1 / 16 inch; the T-type tee is made of polyetheretherketone, and the threaded interface size is 1 / 16 inch; the flexible sleeve is made of fluorinated ethylene propylene copolymer, with an outer diameter of 1 / 16 inch, an inner diameter of 350 microns, and a length of 2 cm; the fused silica capillary has an outer diameter of 320 microns, an inner diameter of 200 microns, and a length of 2.5 cm; the tungsten filament has an outer diameter of 100 microns, and the distance between one end of the tungsten filament in the fused silica capillary and the end of the fused silica capillary close to the mass spectrometer is 0.5 cm; the distance between the fused silica capillary and the inlet of the mass spectrometer is 1-3 cm.

[0013] The detection method of volatile organic compounds in leather using the online detection device of the present invention comprises the following steps:

[0014] (A) assembling and building an online detection device for volatile organic compounds in leather;

[0015] (B) Cutting leather samples and adding them into a glass conical flask;

[0016] (C) Adjust the helium flow rate, set the voltage and frequency of the high-frequency, high-voltage AC power supply, turn on the desktop infrared heating lamp to irradiate and heat the glass conical flask; turn on the temperature display to display the ambient temperature of the leather sample in the glass conical flask in real time; adjust the mass spectrometer to the "operation" state to collect mass spectrometry data in real time.

[0017] The detection method described in the present invention comprises the following steps: cutting the leather sample into a size of 5 cm×5 cm, adjusting the helium flow rate to 60 mL / min; setting the voltage of the high-frequency, high-voltage AC power supply to 3.0 kV and the frequency to 10 kHz; setting the power of the desktop infrared heating lamp to 20 W, and heating the ambient temperature around the leather sample to 20 to 100° C.

[0018] The detection method of the present invention, wherein the mass spectrometer is set to full scan mode, the mass-to-charge ratio range is 100-1000, the maximum ion injection time is 100ms, and the ion capacity is 1e 6 .

[0019] The online detection device for volatile organic compounds in leather of the present invention is different from the prior art in that:

[0020] The present invention's online detection device for volatile organic compounds in leather has the advantages of simple structure, low cost, and easy operation. It eliminates the tedious and complex sample pretreatment steps in conventional detection methods, enabling online detection of volatile organic compounds in leather samples at different ambient temperatures, significantly improving detection efficiency and reducing solvent consumption. Furthermore, the present device, designed and developed based on the principles of microtube plasma, consumes only 50 mL / min of helium, compared to 3000 mL / min of conventional plasma ionization devices, resulting in energy savings.

[0021] The method of the present invention enables efficient and accurate online detection. By simulating the release mechanism of volatile organic compounds (VOCs) in leather under variable temperature conditions and combining it with a highly sensitive online mass spectrometry detection method, the method significantly improves the extraction efficiency and detection accuracy of VOCs, supports online detection, and provides reliable technical support for environmental compliance, quality control, and process optimization in the leather industry.

[0022] The on-line detection device and method for volatile organic compounds in leather of the present invention will be further described below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1Schematic diagram of the structure of the online detection device for volatile organic compounds in leather of the present invention;

[0024] Figure 2 This is a graph showing the online detection results of volatile organic compounds in leather at 80 degrees Celsius in an embodiment of the present invention; wherein the substances are: Butanone-butanone; DMF-dimethyl sulfoxide; NMP-N-methylpyrrolidone; DMB-dimethylbutane; DEGBE-diethylene glycol monobutyl ether; DEGDEE-diethylene glycol diethyl ether; TEGEE-triethylene glycol monoethyl ether; TEGBE-triethylene glycol monobutyl ether; DEGDBE-triethylene glycol dibutyl ether. DETAILED DESCRIPTION

[0025] like Figure 1 As shown, the online detection device for volatile organic compounds in leather of the present invention includes a volatile organic compound collector, a microtube plasma generator and a mass spectrometer 9. The volatile organic compound collector includes a container 1 with an opening and a sealing plug arranged at the opening thereof, and the two form a closed space. One end of the first gas pipeline 13 is connected to the helium source 2, and the other end passes through the sealing plug and is connected to the bottom space inside the container 1. One end of the second gas pipeline 14 is connected to the microtube plasma generator, and the other end passes through the sealing plug and is connected to the upper space inside the container 1; the microtube plasma generator includes a T-shaped tee 4, and the T-shaped tee 4 includes a horizontal pipeline and a vertical pipeline that are interconnected. One end of the horizontal pipeline is connected to the second gas pipeline 14, and a fused silica capillary 6 is arranged inside the other end. One end of the fused silica capillary 6 is arranged inside the horizontal pipeline, and the other end passes through the horizontal pipeline and is close to the mass spectrometer 9.

[0026] Preferably, the device further includes a tungsten filament 7, one end of which is disposed within a fused silica capillary 6 and the other end of which extends through the vertical pipeline of the T-junction 4 and is connected to a high-frequency, high-voltage AC power source 8. The device further includes a flexible sleeve 5, which is sleeved over the fused silica capillary 6. The flexible sleeve 5, the fused silica capillary 6, the horizontal pipeline of the T-junction 4, and the inlet of the mass spectrometer 9 are coaxially arranged horizontally. The three interfaces of the T-junction 4 are sealed with threaded plugs. The flexible sleeve 5 and the T-junction 4, the second gas pipeline 14 and the T-junction 4, the tungsten filament 7 and the T-junction 4, and the flexible sleeve 5 and the fused silica capillary 6 must all be sealed.

[0027] The leather sample is placed at the bottom of container 1. The device also includes a temperature measurement device consisting of a thermocouple 11 and a temperature display 12. The thermocouple 11 is placed inside container 1 near the leather sample to accurately measure the ambient temperature surrounding the sample. One end of a wire is connected to the thermocouple 11, while the other end passes through the sealing plug and connects to the temperature display 12 outside the container 1. The first gas line 13, the second gas line 14, the thermocouple 11, and the sealing plug must remain sealed.

[0028] The device also includes a desktop infrared heating lamp 10, the power and angle of which can be adjusted, for irradiating and heating the container 1 during testing.

[0029] The container 1 is a glass conical flask (500 mL), the helium source 2 is a high-purity helium cylinder, a gas flow controller 3 is provided on the first gas line 13, and the sealing plug is a perforated rubber plug; the first gas line 13 and the second gas line 14 are polytetrafluoroethylene hoses with an outer diameter of 1 / 16 inch; the T-type tee 4 is made of polyetheretherketone, and the threaded interface size is 1 / 16 inch; the flexible sleeve 5 is made of fluorinated ethylene propylene copolymer, with an outer diameter of 1 / 16 inch, an inner diameter of 350 microns, and a length of 2 cm; the fused silica capillary 6 has an outer diameter of 320 microns, an inner diameter of 200 microns, and a length of 2.5 cm; the tungsten filament 7 has an outer diameter of 100 microns, and the distance between one end of the tungsten filament 7 in the fused silica capillary 6 and the end of the fused silica capillary 6 close to the mass spectrometer 9 is 0.5 cm; the distance between the fused silica capillary 6 and the inlet of the mass spectrometer 9 is 1-3 cm, preferably 1 cm.

[0030] The detection method of volatile organic compounds in leather using the online detection device of the present invention comprises the following steps:

[0031] (A) Assembling and building an online detection device for volatile organic compounds in leather;

[0032] (B) Cut the leather sample into 5 cm × 5 cm pieces and place them in a glass conical flask;

[0033] (C) Adjust the helium flow rate to 60mL / min, set the voltage of the high-frequency high-voltage AC power supply 8 to 3.0kV and the frequency to 10kHz; turn on the desktop infrared heating lamp 10, set the power to 20W, in this embodiment, the irradiation angle is 60 degrees to the vertical direction, and the glass conical flask is irradiated and heated; heat the ambient temperature around the leather sample to 20-100°C, 80°C is used in this embodiment. Turn on the temperature display 12 to display the ambient temperature of the leather sample in the glass conical flask in real time; adjust the mass spectrometer 9 to the "operation" state to collect mass spectrum data in real time. The mass spectrometer 9 is set to full scan mode, the mass-to-charge ratio range is 100-1000, the maximum ion injection time is 100ms, and the ion capacity is 1e 6.

[0034] Test results such as Figure 2 As shown in the figure, the test results at 80℃ show that as the temperature rises, the types of volatile organic compounds in the leather detected by the device of the present invention gradually increase. Figure 2 The device demonstrated mass spectrometry results at 80°C. Through accurate mass matching, nine volatile organic compounds (VOCs) were identified: butanone, dimethyl sulfoxide, N-methylpyrrolidone, dimethylbutane, diethylene glycol monobutyl ether, diethylene glycol diethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, and triethylene glycol dibutyl ether. These compounds are primarily organic solvents used in the leather production process and are released at high temperatures. This result demonstrates that the device can achieve online detection of VOCs in leather at different temperatures, providing technical support for safe leather production processes.

[0035] The working principle of the device of the present invention is as follows:

[0036] The leather sample is placed in a sealed glass conical flask. Helium gas carries the volatile organic compounds in the leather through a catheter into a microtube plasma generator. Under the action of high-frequency, high-voltage alternating current, the helium gas is broken down to produce plasma. The plasma reacts with the volatile organic compounds to form molecular ions, thereby ionizing the organic matter and entering the mass spectrometer for online detection. Under the irradiation of the infrared heating lamp, the ambient temperature of the leather continues to rise, and the volatile organic compounds it releases also change continuously and are monitored in real time by the mass spectrometer. The device of the present invention can realize the online detection of volatile organic compounds in leather, providing reliable technical support for environmental compliance, quality control and process optimization in the leather industry.

[0037] The embodiments described above are merely descriptions of preferred implementations of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should fall within the scope of protection determined by the claims of the present invention.

Claims

1. An online detection device for volatile organic compounds in leather, characterized by: The invention comprises a volatile organic compound trap, a microtube plasma generator and a mass spectrometer (9), wherein the volatile organic compound trap comprises a container (1) with an opening and a sealing plug arranged at the opening, one end of a first gas pipeline (13) is connected to a helium source (2), and the other end passes through the sealing plug and is connected to the bottom space inside the container (1); one end of a second gas pipeline (14) is connected to the microtube plasma generator, and the other end passes through the sealing plug and is connected to the upper space inside the container (1); The microtube plasma generator comprises a T-shaped tee (4), wherein the T-shaped tee (4) comprises a horizontal pipeline and a vertical pipeline that are interconnected, wherein one end of the horizontal pipeline is connected to the second gas pipeline (14), and a fused silica capillary (6) is arranged inside the other end, wherein one end of the fused silica capillary (6) is arranged inside the horizontal pipeline, and the other end passes through the horizontal pipeline and is close to the mass spectrometer (9).

2. The on-line detection device for volatile organic compounds in leather according to claim 1, characterized in that: The device also includes a tungsten wire (7), one end of which is arranged inside the fused silica capillary (6), and the other end of which passes through the vertical pipeline of the T-shaped tee (4) and is connected to a high-frequency high-voltage AC power supply (8).

3. The online detection device for volatile organic compounds in leather according to claim 2, characterized in that: The device further comprises a flexible sleeve (5) which is sleeved on the fused silica capillary (6); the flexible sleeve (5), the fused silica capillary (6), the horizontal pipeline of the T-shaped tee (4) and the inlet of the mass spectrometer (9) are coaxially arranged horizontally; and the three interfaces of the T-shaped tee (4) are all sealed with threaded plugs.

4. The on-line detection device for volatile organic compounds in leather according to claim 3, characterized in that: The leather sample is arranged at the bottom of the interior of the container (1).

5. The on-line detection device for volatile organic compounds in leather according to claim 4, characterized in that: The device also includes a temperature measuring device, which consists of a thermocouple (11) and a temperature display (12). The thermocouple (11) is arranged inside the container (1) near the leather sample. One end of the wire is connected to the thermocouple (11), and the other end passes through the sealing plug and is connected to the temperature display (12) outside the container (1).

6. The on-line detection device for volatile organic compounds in leather according to claim 5, characterized in that: The device also includes a desktop infrared heating lamp (10) with adjustable power and angle, which irradiates and heats the container (1) during testing.

7. The on-line detection device for volatile organic compounds in leather according to claim 6, characterized in that: The container (1) is a glass conical flask, the helium source (2) is a high-purity helium cylinder, a gas flow controller (3) is provided on the first gas pipeline (13), and the sealing plug is a perforated rubber plug; the first gas pipeline (13) and the second gas pipeline (14) are polytetrafluoroethylene hoses with an outer diameter of 1 / 16 inch; the T-type tee (4) is made of polyetheretherketone, and the thread interface size is 1 / 16 inch; the flexible sleeve (5) is made of fluorinated ethylene propylene copolymer, and the outer diameter is 1 / 1 6 inches, an inner diameter of 350 microns, and a length of 2 cm; the outer diameter of the fused silica capillary (6) is 320 microns, the inner diameter is 200 microns, and the length is 2.5 cm; the outer diameter of the tungsten filament (7) is 100 microns, and the distance between one end of the tungsten filament (7) in the fused silica capillary (6) and the end of the fused silica capillary (6) close to the mass spectrometer (9) is 0.5 cm; the distance between the fused silica capillary (6) and the inlet of the mass spectrometer (9) is 1-3 cm.

8. The detection method using the online detection device for volatile organic compounds in leather according to claim 7, characterized in that: The steps include: (A) assembling and building an online detection device for volatile organic compounds in leather; (B) Cutting leather samples and adding them into a glass conical flask; (C) Adjust the helium flow rate, set the voltage and frequency of the high-frequency high-voltage AC power supply (8), turn on the desktop infrared heating lamp (10), and irradiate and heat the glass conical flask; turn on the temperature display (12) to display the ambient temperature of the leather sample in the glass conical flask in real time; adjust the mass spectrometer (9) to the "operation" state to collect mass spectrum data in real time.

9. The detection method according to claim 8, wherein: The leather sample is cut into a size of 5 cm×5 cm, and the helium flow rate is adjusted to 60 mL / min; the voltage of the high-frequency high-voltage AC power supply (8) is set to 3.0 kV, and the frequency is set to 10 kHz; the power of the desktop infrared heating lamp (10) is set to 20 W, and the ambient temperature around the leather sample is heated to 20-100° C.

10. The detection method according to claim 9, characterized in that: The mass spectrometer (9) was set to full scan mode, with a mass-to-charge ratio range of 100-1000, a maximum ion injection time of 100 ms, and an ion capacity of 1e 6 .

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