Method for measuring gas-liquid and gas-liquid-solid partition coefficients of atmospheric organic amines, and use thereof

Abstract

A method for measuring gas-liquid and gas-liquid-solid partition coefficients of atmospheric organic amines, and the use thereof. The method comprises: atomizing an organic amine solution by means of an aerosol generator to generate an aerosol; and, after drying treatment, using a proton transfer reaction time-of-flight mass spectrometer to measure online the concentrations of organic amines in a gas phase and a particle phase, and using a scanning mobility particle sizer to measure the particle size distribution and total mass concentration of organic amine particles, so as to calculate partition coefficients. The technique achieves simple operation and rapid measurement, and is of great significance for understanding the migration and transformation of organic amines in the atmosphere. Further provided is a system for implementing the measurement method, the system comprising an aerosol generator, a Nafion dryer, a PFA particle filter, a real-time analysis sample inlet system, a proton transfer reaction time-of-flight mass spectrometer and a scanning mobility particle sizer. The present invention can be widely applied to environmental chemical analysis, providing technical support for the study of pollution characteristics of atmospheric organic amines.

Description

A method for measuring the gas-liquid and gas-liquid-solid partition coefficients of atmospheric organic amines and its application. Technical Field

[0001] This invention belongs to the field of atmospheric chemical composition analysis technology. More specifically, this invention relates to a method for measuring the gas-liquid and gas-liquid-solid partition coefficients of atmospheric organic amines and their applications. Background Technology

[0002] Organic amines are a class of nitrogen-containing organic compounds in the atmosphere with properties such as alkalinity and viscosity. Recently, the role of amines in particle nucleation and growth has reignited interest in the gas-to-particle distribution of organic amines in the atmosphere. Previous studies on the distribution coefficients of organic amines have mostly relied on theoretical calculations or field monitoring. Theoretical values ​​can only assess the distribution process under ideal conditions; however, organic amine aerosols in the actual atmosphere are complex mixed systems, making it impossible to determine the distribution patterns of organic amines in a single gas-liquid two-phase or gas-liquid-solid three-phase system. Because the mass fraction of organic amine aerosol particles is extremely low compared to the gas phase, the assessment of organic amines is limited. The detection of amines in the particulate phase is mostly done offline, characterized by complex pretreatment processes, numerous steps, and long processing times. Gas-phase amines are mostly detected by online mass spectrometry, but there is still no online detection method that simultaneously collects both gas-phase and particulate-phase organic amines. Therefore, a method for simultaneous online detection of the gas-phase and particulate-phase concentrations of organic amines in aerosols is lacking.

[0003] Existing technologies disclose an analytical method for simultaneously collecting and detecting organic amines in the gaseous and particulate phases of the atmosphere. After collecting the gaseous and particulate phases, organic amine derivatization solutions are prepared and detected using an automated gas chromatograph and mass spectrometer. However, this method is complex, difficult to implement rapidly, and does not explore the partition coefficients and patterns of organic amines. Existing technologies also disclose a method for measuring the deposition rate of volatile organic compounds (VOCs) in atmospheric particulate matter in the human respiratory tract. This method uses a real-time aerosol chemical composition analysis injection system combined with a proton transfer reaction time-of-flight mass spectrometer to detect the composition of various VOCs with a proton affinity greater than water on particulate matter in exhaled breath. However, the instrument control used is insufficient for the determination of organic amines.

[0004] Therefore, developing a method for measuring the gas-liquid and gas-liquid-solid partition coefficients of atmospheric organic amines and its application, so as to realize the rapid and simple measurement of organic amines in the gas phase and particulate phase and the analysis of the partition law of organic amines, has important research significance and application value. Summary of the Invention

[0005] The present invention aims to overcome the shortcomings of the prior art and provide a method for measuring the gas-liquid and gas-liquid-solid partition coefficients of atmospheric organic amines and its application, so as to realize the rapid and simple measurement and analysis of the partition law of organic amines in the gas phase and particulate phase.

[0006] Therefore, the primary objective of this invention is to provide a method for measuring the gas-liquid and gas-liquid-solid partition coefficients of atmospheric organic amines.

[0007] Another object of the present invention is to provide a system for measuring the gas-liquid and gas-liquid-solid partition coefficients of atmospheric organic amines.

[0008] Another object of the present invention is to provide an application of the above-described measurement method.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] This invention protects a method for measuring the gas-liquid and gas-liquid-solid partition coefficients of atmospheric organic amines, comprising the following steps:

[0011] S1. Prepare an organic amine solution;

[0012] S2. Atomize the organic amine solution into organic amine aerosol using an integrated aerosol generator, and then dry it;

[0013] S3. The particle size distribution and total mass concentration of organic amine particles were determined using a scanning electromobility particle size analyzer;

[0014] S4. A real-time aerosol chemical composition analysis sample introduction system coupled with a proton transfer reaction time-of-flight mass spectrometer was used to detect the concentration of organic amine particles and the concentration of organic amine gas phase by switching software.

[0015] S5. The distribution coefficient of the organic amine is obtained by dividing the particulate phase concentration of the organic amine by the product of the gas phase concentration and the total particulate matter mass concentration.

[0016] In step S1, the concentration of the organic amine solution is 3~10M;

[0017] The parameters of the aerosol chemical composition real-time analysis injection system in step S4 are set as follows: thermal desorption temperature is 60~180℃.

[0018] This invention generates organic amine aerosols using an integrated aerosol generator. The total mass concentration of the nano-aerosol particles is detected by scanning electromobility particle size analyzer (SEM). Then, the concentrations of organic amines in both the gas and particulate phases are simultaneously detected by a real-time aerosol chemical composition analysis sample introduction system coupled with a proton transfer reaction time-of-flight mass spectrometer (PTF-MS / MS), and the partition coefficient is calculated. This invention innovatively proposes a method for directly introducing an organic amine solution into an integrated aerosol generator to obtain aerosols. This invention sets a concentration range for the organic amine solution entering the integrated aerosol generator, requiring a concentration above 3 M. Simultaneously, the detection instrument also has requirements for the lower limit of detection (lower limit of concentration) of organic amines. Too low a concentration may result in a weak detection signal, failing to reach the detector's detection limit. Concentrations cannot exceed 10 M, as excessively high concentrations will exceed the instrument's detection range.

[0019] When setting parameters for a real-time aerosol chemical composition analysis sample introduction system coupled with a proton transfer reaction time-of-flight mass spectrometer, the thermal desorption temperature plays a crucial role. The principle behind setting the thermal desorption temperature range for organic amines involves the volatility, thermal stability, and instrument detection efficiency of the organic amines. Excessively high temperatures can destroy organic amines, leading to a decrease in the measured concentration. Controlling the temperature range ensures that all organic amines in the particulate matter volatilize, guaranteeing measurement accuracy while preventing high-temperature destruction. Below 60°C, the thermal motion of organic amine molecules slows down, reducing the probability of their transfer from the particulate phase to the gas phase. This reduces the amount of organic amine volatilized, weakening the detection signal and affecting the sensitivity and accuracy of the detection.

[0020] The organic amine solution mentioned in step S1 can be any type of organic amine in the prior art.

[0021] Preferably, the organic amine solution in step S1 is either dimethylamine or cyclohexylamine.

[0022] Preferably, the volume of the organic amine solution in step S2 is 10~50 mL, which is the volume of the organic amine solution entering the aerosol generator.

[0023] Preferably, the flow rate of the integrated aerosol generator in step S2 is 1.5~2.5L / min.

[0024] Preferably, the time for the organic amine solution to generate organic amine aerosol in step S2 is 1 to 10 minutes.

[0025] Specifically, the drying step in step S2 includes: first, generating a two-hour aerosol sample through a Teflon tube and collecting it in a waste gas bag, the purpose of which is to ensure that the Teflon tube has reached the particulate matter absorption-release balance on the tube wall before sampling.

[0026] Preferably, the parameters of the integrated aerosol generator in step S2 are: at room temperature (25±2℃), the relative humidity of the dried aerosol sample is maintained at 35±5%, measured using an RH / temperature probe.

[0027] Preferably, the parameters of the scanning mobility particle size spectrometer in step S3 are set as follows: sheath flow rate of 3 L / min, sampling flow rate of 0.3 L / min, and scanning time of 392~1000 s.

[0028] Specifically, the scanning electromobility particle size analyzer includes an electrostatic classifier, a differential electromobility analyzer, and a condensed nucleus particle counter. The electrostatic classifier includes a single-stage inertial impactor and a radioactive neutralizer.

[0029] Specifically, the method for detecting the particle size distribution and total mass concentration of organic amine particles in step S3 is as follows: the dried organic amine aerosol in step S2 enters a single-stage inertial impactor to remove large particles outside the instrument's measurement range, then enters an electrostatic classifier and a differential electromobility analyzer to distinguish particles of different size ranges, and then enters a condensation nucleus particle counter for counting.

[0030] Specifically, the aerosol chemical composition real-time online analysis sample introduction system in step S4 includes a gas phase stripper, an aerodynamic lens, and a thermal desorption device.

[0031] Preferably, the parameters of the aerosol chemical composition real-time analysis injection system in step S4 are set as follows: the energy level E / N value of the drift tube is 60~150TD.

[0032] Specifically, the parameters of the aerosol chemical composition real-time analysis injection system in step S4 are set as follows: desorption temperature of 60~180℃, drift tube pressure of 2.3 bar, temperature of 120℃, and energy level E / N value of 60~150TD, where E is the electric field strength, and its unit is 1TD=10 -17 v cm², where N is the number density of a neutral gas.

[0033] Specifically, the proton transfer reaction time-of-flight mass spectrometry described in step S4 includes an ion source, a drift tube, a mass separator, and an ion detector.

[0034] Preferably, the parameters of the gas quantum transfer time-of-flight mass spectrometer in step S4 are set as follows: drift tube pressure is 2.9 bar, temperature is 120°C, and energy level E / N value is 60~150 TD, where E is the electric field strength, and its unit is 1 TD = 10⁻⁶. -17 v cm², where N is the number density of a neutral gas.

[0035] Preferably, the proton transfer time-of-flight mass spectrometer is calibrated using a dimethylamine permeation tube system in step S4.

[0036] The present invention also protects a system for measuring the gas-liquid and gas-liquid-solid partition coefficients of atmospheric organic amines, the system comprising an integrated aerosol generator, a Nafion dryer, a PFA particle filter, a real-time aerosol chemical composition analysis and injection system, a proton transfer reaction time-of-flight mass spectrometer, and a scanning electromobility particle size spectrometer.

[0037] Specifically, the system for measuring the gas-liquid and gas-liquid-solid partition coefficients of atmospheric organic amines includes the following embodiments:

[0038] An aerosol generator produces organic amine aerosol samples at a certain flow rate. The nozzle is connected to a Nafion dryer for drying. The samples first pass through a scanning electromobility particle size analyzer to detect the particle size distribution and total mass concentration of the organic amine particles. Then, they enter the aerosol chemical composition real-time analysis sample introduction system, where a gas phase stripper efficiently adsorbs organic gases and transfers particulate matter. Subsequently, an aerodynamic lens enriches the particles, and a thermal desorber volatilizes the organic components from the particles into the gas phase. Finally, proton transfer reaction time-of-flight mass spectrometry (PTF-MS) detects these organic compounds. Excess gas is discharged into a waste gas bag through a connected three-way valve. Before entering the instrument for detection, the gas phase organic amines require a PFA particulate filter to remove particulate matter. The aerosol chemical composition real-time analysis sample introduction system coupled with the PTF-MS detects the concentrations of organic amines in both the gas and particulate phases, and the instrument parameters are adjusted via software switching.

[0039] The step S4, which measures the concentration of organic amine particles and the concentration of organic amine gas, consists of two parts: detecting the concentration of organic amine gas and detecting the concentration of organic amine particles.

[0040] Detection of gaseous organic amine concentration: H3O was selected for proton transfer time-of-flight mass spectrometry. + As an ion source, the proton affinity of organic amines is greater than that of water, and gaseous organic amines react with H3O. + A proton transfer reaction occurs, enabling the detection of the corresponding organic amine ion signal. Detection of particulate organic amine concentration: In the real-time aerosol chemical composition analysis sample introduction system, the gas phase stripper removes the gaseous organic amine, and a thermal desorption device volatilizes the organic amine in the particles into a gas, which is then introduced into a proton transfer time-of-flight mass spectrometer for concentration detection.

[0041] Specifically, the concentration data analysis of organic amines in the gas phase and particulate phase in step S4 is as follows: each sample reaches a peak and remains stable. Based on the curves indicating different organic amines for each sample, the average value of the rising to plateau phase is taken to obtain the corresponding concentration value. The measured concentration signal values ​​of organic amines in the gas phase and particulate phase are replaced by a plotted standard curve to ensure the accuracy of the data.

[0042] The application of a method for measuring the gas-liquid and gas-liquid-solid partition coefficients of atmospheric organic amines in environmental chemical analysis is also within the scope of protection of this invention.

[0043] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0044] This invention provides a method for measuring the gas-liquid and gas-liquid-solid partition coefficients of atmospheric organic amines. Organic amine aerosols are generated using an integrated aerosol generator. The concentrations of organic amines in the gas and particulate phases, as well as the total mass concentration of particulate matter, are measured. The partition coefficients of different organic amines in the gas-liquid and gas-liquid-solid phases are calculated. This method can be applied to the quantitative analysis of various organic amines in gas and particulate phase samples in the atmospheric environment. It is characterized by its simple operation and can provide important technical support for the detection and evaluation of the partition coefficients of organic amines in the atmospheric environment. Attached Figure Description

[0045] Figure 1 is a flowchart of a method for measuring the gas-liquid and gas-liquid-solid partition coefficients of atmospheric organic amines according to the present invention.

[0046] Figure 2 shows the concentration of organic amines in the gas phase and particulate phase in the cyclohexylamine aerosol sample of Example 2.

[0047] Figure 3 shows the particle size distribution of the nanoparticle phase in the cyclohexylamine aerosol sample of Example 2. Embodiments of the present invention

[0048] To more clearly and completely describe the technical solution of the present invention, the present invention will be further described in detail below through specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention. Various changes can be made within the scope of the claims of the present invention.

[0049] Unless otherwise specified, all reagents and materials used in the following examples are commercially available.

[0050] Example 1: A method for measuring the gas-liquid and gas-liquid-solid partition coefficients of atmospheric organic amines and its application.

[0051] 1. Take 500 μL of 40 wt% dimethylamine solution and dilute to volume in a 500 mL brown volumetric flask to prepare a 3.0 M dimethylamine aqueous solution.

[0052] 2. Take 30 mL of dimethylamine sample aqueous solution into a sampling bottle, turn on the aerosol generator switch, set the aerosol generation flow rate to 1.5 L / min, generate dimethylamine aerosol at the nozzle, and then dry it with a Nafion drying tube at room temperature (25±2℃) and relative humidity maintained at 35±5%.

[0053] 3. Before collection and detection, the generated aerosol samples are first collected in a waste gas bag through a Teflon tube for 2 hours to ensure the adsorption-release equilibrium of particulate matter on the Teflon tube wall. Before each sample introduction, the online real-time analysis sample introduction system for aerosol chemical composition coupled with proton transfer time-of-flight mass spectrometry is first purged with nitrogen for 30 minutes to clean the instrument of any residues, and the cleaned signal value is used as blank data.

[0054] 4. An aerosol generator atomizes dimethylamine aqueous solution to produce an aerosol sample. This sample is dried in a Nafion drying tube via a Teflon tube, and then enters a scanning mobility spectrometer (SMPS) through a three-way valve to detect the total mass concentration of nanoparticles. Another portion enters the CHARON aerosol chemical composition real-time analysis sample introduction system, where a gas phase stripper efficiently adsorbs dimethylamine gas and transfers nanoparticles. These particles are then enriched by an aerodynamic lens, and a thermal desorption system converts the particulate dimethylamine into a gaseous phase. Finally, proton transfer reaction time-of-flight mass spectrometry detects the gaseous dimethylamine using soft ionization with hydrated hydrogen ions, and the mass spectrum is plotted and transmitted to a computer display. The remaining sample is collected in a waste gas bag via a three-way valve. The connecting pipes are rinsed with high-purity N2 free of particulate matter before the next sample is analyzed.

[0055] 5. Based on the exploration, the optimal parameters obtained are: the thermal desorption temperature of the online real-time analysis sample introduction system for aerosol chemical composition is 150℃, the drift tube pressure is 2.3 bar, and the energy level (E / N) value of the drift tube is 145TD (E is the electric field strength, and its unit is 1TD=10). -17 v cm², where N is the number density of the neutral gas), detection time is 1~10 min. The sheath flow rate of the scanning electromobility particle size spectrometer is 3 L / min, the sampling flow rate is 0.3 L / min, and the scanning time is 392~1000 s.

[0056] 6. In this embodiment, dimethylamine aerosol was selected for generation and gas-particle concentration detection. The gas-phase dimethylamine detection method involves generating dimethylamine pure water aerosol using an aerosol generator at a flow rate of 1.5 L / min. The aerosol enters a Nafion drying tube through a Teflon tube for drying, and then passes through a PFA particulate filter to trap particulate matter on the filter membrane. A portion of the gas-phase dimethylamine enters a proton transfer time-of-flight mass spectrometer (PTR-ToF-MS) through a three-way valve for detection, while the remaining portion is discharged as residual gas and collected using a waste gas bag.

[0057] 7. Based on the exploration, the optimal parameters obtained are: the pressure of the drift tube of the proton transfer time-of-flight mass spectrometer is 2.9 bar, and the energy level (E / N) value of the drift tube is 145 TD (E is the electric field strength, and its unit is 1 TD = 10⁻⁶). -17 v cm², where N is the number density of the neutral gas. Detection time is 1~10 min.

[0058] 8. In this embodiment, a dimethylamine permeation tube system is used to calibrate the proton transfer time-of-flight mass spectrometer. The standard gas generated by the permeation tube is diluted with high-purity nitrogen, a concentration gradient is set, and a standard curve is plotted. Figure 1 is a schematic diagram of the structure of the method for measuring the partition coefficient of organic amines on particles according to the present invention. It includes an integrated aerosol generator, a Nafion drying tube, a PFA particle filter, a three-way valve, a waste gas bag, a proton transfer time-of-flight mass spectrometer (PTR-ToF-MS), a real-time aerosol chemical composition analysis and injection system (CHARON), and a scanning electromobility particle size analyzer (SMPS); the partition coefficient formula is: K P =C p / (C g ×TSP), where C p and C g The concentrations (μg m) of organic compounds in the particulate and gaseous phases, respectively. -3 TSP here refers to the total mass concentration of nano-aerosol particles (μg m³). -3 The gas-particle phase signal value was replaced by the value on the standard curve, and the partition coefficient of dimethylamine in pure water aerosol was calculated to be (2.3±0.37)×10. -6 m 3 / μg.

[0059] Example 2: A method for measuring the gas-liquid and gas-liquid-solid partition coefficients of atmospheric organic amines and its application.

[0060] 1. The difference from Example 1 is that the detection substance in the parameter settings of this example is cyclohexylamine. The detection results show that 406 μL of 99.5% cyclohexylamine solution was diluted to volume in a 500 mL brown volumetric flask to prepare a 3.0 M cyclohexylamine sample aqueous solution.

[0061] 2. Take 40 mL of cyclohexylamine sample aqueous solution into a sampling bottle. The aerosol generator flow rate is 1.5 L / min. The online real-time analysis sample introduction system for aerosol chemical composition is coupled with a proton transfer time-of-flight mass spectrometer. Based on the curve indicated by cyclohexylamine ((C6H13N)H+ m / z 100.170), the average value is taken from the rising to the plateau region to obtain the corresponding concentration value. The detection time is 50~180 s. The scanning electromobility particle size analyzer scans for 392 s.

[0062] 3. The signal value of cyclohexylamine in the gas-particle phase was replaced by the value from the standard curve. Calculations showed that the partition coefficient of cyclohexylamine in pure water aerosol was (3.0 ± 0.81) × 10⁻⁶. -2 m 3 / μg.

[0063] Example 3: A method for measuring the gas-liquid and gas-liquid-solid partition coefficients of atmospheric organic amines and its application.

[0064] 1. The difference from Example 1 is that the concentration of the dimethylamine solution in the parameter settings of this example is 4.2M, that is, 700μL of 40% dimethylamine solution is taken and diluted to volume in a 500mL brown volumetric flask to prepare a dimethylamine sample aqueous solution.

[0065] 2. Take 50 mL of dimethylamine sample aqueous solution into a sampling bottle. The aerosol generator flow rate is 1.5 L / min. The online real-time analysis sample introduction system for aerosol chemical composition is coupled with a proton transfer time-of-flight mass spectrometer. Based on the curve indicated by dimethylamine ((C2H7N)H+ m / z 46.065) in the sample, the average value is taken from the rising to the plateau region to obtain the corresponding concentration value. The detection time is 70-90 s. The scanning electromobility particle size analyzer scans for 392 s.

[0066] 3. The dimethylamine aerosol signal value was replaced by the value from the standard curve. Calculations showed that the partition coefficient of dimethylamine in aqueous aerosols was (2.0 ± 0.42) × 10⁻⁶. -6 m 3 / μg.

[0067] Example 4: A method for measuring the gas-liquid and gas-liquid-solid partition coefficients of atmospheric organic amines and its application.

[0068] 1. The difference from Example 1 is that the aerosol generation flow rate in the parameter settings of this example is 2L / min.

[0069] 2. Take 50 mL of dimethylamine sample aqueous solution into a sampling bottle. The aerosol generator flow rate is 2 L / min. The online real-time analysis sample introduction system for aerosol chemical composition is coupled with a proton transfer time-of-flight mass spectrometer. Based on the dimethylamine ((C2H7N)H+ m / z 46.065) indicator curve, select the rising to plateau segment and take the average value to obtain the corresponding concentration value. The detection time is 50-70 s. The scanning electromobility particle size analyzer scan time is 588 s.

[0070] 3. The dimethylamine gas-particle phase signal value was replaced by the value from the standard curve. Calculation results show that the partition coefficient of dimethylamine in aqueous aerosols is (1.4 ± 0.77) × 10⁻⁶. -6 m 3 / μg.

[0071] Example 5: A method for measuring the gas-liquid and gas-liquid-solid partition coefficients of atmospheric organic amines and its application.

[0072] 1. The difference from Example 1 is that the sample solution in this example is an aqueous solution of dimethylamine hydrochloride. The test results show that 0.237 g of dimethylamine hydrochloride solid was weighed and diluted to volume in a 500 mL brown volumetric flask to prepare a 3.0 M dimethylamine hydrochloride sample aqueous solution.

[0073] 2. Take 50 mL of dimethylamine sample aqueous solution into a sampling bottle. The aerosol generator flow rate is 1.5 L / min. The online real-time analysis of aerosol chemical composition is coupled with a proton transfer time-of-flight mass spectrometer. Based on the dimethylamine ((C2H7N)H+ m / z 46.065) indicator curve, the average value is taken from the rising to the plateau region to obtain the corresponding concentration value. The detection time is 50-70 s. The scanning electromobility particle size analyzer scans for 588 s.

[0074] 3. The dimethylamine gas-particle phase signal value was replaced by the value from the standard curve. Calculation results show that the partition coefficient of dimethylamine in water-ammonium chloride aerosol is (1.4 ± 0.21) × 10⁻⁶. -3 m 3 / μg.

[0075] Example 6: A method for measuring the gas-liquid and gas-liquid-solid partition coefficients of atmospheric organic amines and its application.

[0076] 1. The difference from Example 1 is that the sample solution in this example is a 3.0M dimethylamine sodium chloride aqueous solution. The test results show that a dimethylamine sodium chloride sample aqueous solution can be prepared by taking 500 μL of a 40% (w / w) dimethylamine solution and weighing 4 g of NaCl solid in a 500 mL brown volumetric flask and making up to volume.

[0077] 2. Take 45 mL of sample solution into a sampling bottle. The aerosol generator flow rate is 2.5 L / min. The online real-time analysis of aerosol chemical composition is performed using a proton transfer time-of-flight mass spectrometer coupled with the sample introduction system. Based on the curve indicated by dimethylamine ((C2H7N)H+ m / z 46.00), the average value is taken from the rising to the plateau region to obtain the corresponding concentration value. The detection time is 80–100 s. The scanning electromobility particle size analyzer scan time is 392 s.

[0078] 3. The dimethylamine gas-particle phase signal value was replaced by the value from the standard curve. Calculation results show that the partition coefficient of dimethylamine in inorganic salt-water aerosol is (3.5 ± 0.40) × 10⁻⁶. -3 m 3 / μg.

[0079] Example 7: A method for measuring the gas-liquid and gas-liquid-solid partition coefficients of atmospheric organic amines and its application.

[0080] 1. The difference from Example 1 is that the organic amine aerosol sample in the parameter settings of this example is a real atmospheric sample from the contaminated site. The results show that ambient air at the contaminated site can be collected in a Teflon gas bag using a vacuum pump.

[0081] 2. Atmospheric samples collected in the gas bag were introduced into an online real-time aerosol chemical composition analysis system coupled with a proton transfer time-of-flight mass spectrometer. The concentrations of organic amines in the gas and particulate phases were measured separately using software switching. Based on the curve indicated by dimethylamine ((C2H7N)H+ m / z 46.065) in the sample, the average value was taken from the rising to the plateau phase to obtain the corresponding concentration value. The detection time was 70–130 s. The scanning electromobility particle size analyzer scan time was 392 s.

[0082] 3. The gas-particle phase signal values ​​of dimethylamine were replaced with the values ​​from the standard curve. Calculation results show that the partition coefficient of dimethylamine in real atmosphere is (38.8 ± 31.66) m. 3 / μg.

[0083] Comparative Example 1: A method for measuring the gas-liquid and gas-liquid-solid partition coefficients of atmospheric organic amines and its application.

[0084] The experimental method is the same as in Example 1, except that the concentration of the dimethylamine solution in step 1 is 2M, and the concentration of the particulate phase is below the detection limit, so it cannot be measured.

[0085] Comparative Example 2: A method for measuring the gas-liquid and gas-liquid-solid partition coefficients of atmospheric organic amines and its application.

[0086] The experimental method is the same as in Example 1, except that the concentration of the dimethylamine solution in step 1 is 11M, and the concentration of the organic amine in the gas phase is too high, exceeding the detection range of the instrument.

[0087] Comparative Example 3: A method for measuring the gas-liquid and gas-liquid-solid partition coefficients of atmospheric organic amines and its application.

[0088] The experimental method is the same as in Example 1, except that the thermal desorption temperature of the online real-time analysis sample introduction system for aerosol chemical composition in step 5 is 50℃.

[0089] The partition coefficient of dimethylamine in aqueous aerosols is (1.5 ± 0.36) × 10⁻⁶. -7 m 3 / μg.

[0090] Comparative Example 4: A method for measuring the gas-liquid and gas-liquid-solid partition coefficients of atmospheric organic amines and its application.

[0091] The experimental method is the same as in Example 1, except that the thermal desorption temperature of the online real-time analysis sample introduction system for aerosol chemical composition in step 5 is 180℃.

[0092] The partition coefficient of dimethylamine in aqueous aerosols is (5.8 ± 0.21) × 10⁻⁶. -7 m 3 / μg.

[0093] The methods for measuring the gas-liquid and gas-liquid-solid partition coefficients of atmospheric organic amines provided in Examples 1-11 enable rapid and convenient measurement of the gas phase and particulate phase of organic amines, with Example 1 being the optimal measurement method.

[0094] In Comparative Example 1, the organic amine concentration was set below the range, and the particulate phase concentration was below the detection limit, making measurement impossible. In Comparative Example 2, the organic amine concentration was above the range, and the gas phase concentration of organic amine was too high, exceeding the instrument's detection range. In Comparative Example 3, the thermal desorption temperature of the online real-time analysis injection system for aerosol chemical components was set below the range, indicating that a low thermal desorption temperature reduces the volatilization of organic amines, weakening the detection signal and affecting the sensitivity and accuracy of the detection. In Comparative Example 4, the thermal desorption temperature was set above the range, resulting in a smaller partition coefficient, which destroyed the organic amines and made the measurement results inaccurate.

[0095] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for measuring the gas-liquid and gas-liquid-solid partition coefficients of atmospheric organic amines, characterized in that, Includes the following steps: S1. Prepare an organic amine solution; S2. Atomize the organic amine solution into organic amine aerosol using an integrated aerosol generator, and then dry it; S3. The particle size distribution and total mass concentration of organic amine particles were determined using a scanning electromobility particle size analyzer; S4. A real-time aerosol chemical composition analysis sample introduction system coupled with a proton transfer reaction time-of-flight mass spectrometer was used to detect the concentration of organic amine particles and the concentration of organic amine gas phase by switching software. S5. The distribution coefficient of the organic amine is obtained by dividing the particulate phase concentration of the organic amine by the product of the gas phase concentration and the total particulate matter mass concentration. In step S1, the concentration of the organic amine solution is 3~10M; The parameters of the aerosol chemical composition real-time analysis injection system in step S4 are set as follows: thermal desorption temperature is 60~180℃.

2. The method according to claim 1, characterized in that, The volume of the organic amine solution in step S1 is 10~50mL, which is the volume of the organic amine solution entering the aerosol generator.

3. The method according to claim 1, characterized in that, The flow rate of the integrated aerosol generator in step S2 is 1.5~2.5L / min.

4. The method according to claim 1, characterized in that, The drying step described in step S2 includes: first, generating a two-hour aerosol sample through a Teflon tube and collecting it in a waste gas bag, the purpose of which is to ensure that the Teflon tube has reached the particulate matter absorption-release equilibrium on the tube wall before sampling.

5. The method according to claim 1, characterized in that, The parameters of the scanning mobility particle size spectrometer in step S3 are set as follows: sheath flow rate is 3 L / min, sampling flow rate is 0.3 L / min, and scanning time is 392~1000 s.

6. The method according to claim 1, characterized in that, The parameters of the proton transfer time-of-flight mass spectrometer in step S4 are set as follows: the energy level E / N value is 60~150TD.

7. The method according to claim 1, characterized in that, The step S4, which measures the concentration of organic amine particles and the concentration of organic amine gas, consists of two parts: detecting the concentration of organic amine gas and detecting the concentration of organic amine particles.

8. A system for measuring the gas-liquid and gas-liquid-solid partition coefficients of atmospheric organic amines according to any one of claims 1 to 7, characterized in that, It includes an integrated aerosol generator, a Nafion dryer, a PFA particle filter, a real-time aerosol chemical composition analysis and injection system, a proton transfer reaction time-of-flight mass spectrometer, and a scanning electromobility particle size spectrometer.

9. The system for measuring the gas-liquid and gas-liquid-solid partition coefficients of atmospheric organic amines according to claim 8, characterized in that, The following implementation methods are included: An aerosol generator produces organic amine aerosol samples at a certain flow rate. The nozzle is connected to a Nafion dryer for drying. The samples first pass through a scanning electromobility particle size analyzer to detect the particle size distribution and total mass concentration of the organic amine particles. Then, they enter the aerosol chemical composition real-time analysis sample introduction system, where a gas phase stripper efficiently adsorbs organic gases and transfers particulate matter. Subsequently, an aerodynamic lens enriches the particles, and a thermal desorber volatilizes the organic components from the particles into the gas phase. Finally, proton transfer reaction time-of-flight mass spectrometry (PTF-MS) detects these organic compounds. Excess gas is discharged into a waste gas bag through a connected three-way valve. Before entering the instrument for detection, the gas phase organic amines require a PFA particulate filter to remove particulate matter. The aerosol chemical composition real-time analysis sample introduction system coupled with the PTF-MS detects the concentrations of organic amines in both the gas and particulate phases, and the instrument parameters are adjusted via software switching.

10. The application of a method for measuring the gas-liquid and gas-liquid-solid partition coefficients of atmospheric organic amines according to any one of claims 1 to 7 in environmental chemical analysis.

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