Measurement method of atmospheric organic amine gas-liquid and gas-liquid-solid partition coefficient and application thereof

Abstract

The invention relates to the technical field of atmospheric chemical analysis, and provides a method for measuring atmospheric organic amine gas-liquid and gas-liquid-solid partition coefficients and application of the method. The method comprises the following steps: atomizing an organic amine solution through an aerosol generator to generate aerosol, drying, quantitatively detecting the concentration of gas-phase and particle-phase organic amine on line by using a proton transfer time-of-flight mass spectrometer and a scanning mobility particle size spectrometer, and further calculating the partition coefficient. The technology is easy and convenient to operate and rapid in detection, and has important significance for understanding migration and transformation of organic amine in the atmosphere. The invention further provides a system for realizing the measuring method, the system comprises an aerosol generator, a dryer, a particle filter, a real-time analysis sampling system, a time-of-flight mass spectrometer and the like, and the system can be widely applied to environmental chemical analysis and provides technical support for research on atmospheric organic amine pollution characteristics.

Description

Technical Field

[0001] The invention belongs to the technical field of atmospheric chemical component analysis, and more specifically, to a method for measuring the gas-liquid and gas-liquid-solid distribution coefficients of atmospheric organic amines and applications thereof. Background Art

[0002] Organic amines are a class of nitrogen-containing organic compounds in the atmosphere that have alkalinity, viscosity and other characteristics. Recently, the role of amines in particle nucleation and growth has revived interest in the distribution of organic amines from gas to particles in the atmosphere. Previous studies on the distribution coefficients of organic amines were mostly predicted by theoretical calculations or obtained by field monitoring. The theoretical values ​​can only evaluate the distribution process under ideal conditions. In the actual atmosphere, organic amine aerosols belong to a mixed and complex system, and it is impossible to derive the distribution law of organic amines in a single gas-liquid two-phase or gas-liquid-solid three-phase. Since the mass fraction of organic amine aerosol particles is extremely low compared with the gas phase, the evaluation of organic amines is limited. The detection of particle-phase amines is mostly an offline detection method, which has the characteristics of complex pretreatment process, many steps and long time. Gas-phase amines are mostly detected by online mass spectrometry, but there is no online detection method that can simultaneously collect gas-phase and particle-phase organic amines. Therefore, there is a lack of simultaneous online detection methods for the gas-phase and particle-phase concentrations of organic amines in aerosols.

[0003] The prior art discloses an analytical method for simultaneously collecting and detecting gaseous and particulate organic amines in the atmospheric environment. After collecting the gaseous and particulate phases, an organic amine derivatization solution is prepared and detected by an automatic gas chromatograph and mass spectrometer. However, the analytical method is complicated and difficult to achieve rapid analysis. The distribution coefficient and law of organic amines are not explored. The prior art discloses a method for measuring the deposition rate of volatile organic compounds in atmospheric particulate matter in the human respiratory tract. The composition of various volatile organic compounds with proton affinity greater than water on particulate matter in human exhaled breath is detected by combining an aerosol chemical composition real-time analysis sampling system with a proton transfer reaction time-of-flight mass spectrometer. However, the instrument control used cannot meet the determination of organic amines.

[0004] Therefore, developing a measurement method for the gas-liquid and gas-liquid-solid distribution coefficients of atmospheric organic amines and its application, realizing rapid and convenient measurement of the gas and particle phases of organic amines, and analyzing the distribution laws of organic amines have important research significance and application value. Summary of the invention

[0005] The present invention aims to overcome the deficiencies of the prior art and provide a method for measuring the gas-liquid and gas-liquid-solid distribution coefficients of atmospheric organic amines and its application, so as to achieve rapid and convenient measurement of the gas phase and particle phase of the organic amines and analyze the distribution law of the organic amines.

[0006] Therefore, the primary object of the present 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-mentioned measuring method.

[0009] To achieve the above object, the present invention adopts the following technical solutions:

[0010] The present invention provides a method for measuring the gas-liquid and gas-liquid-solid partition coefficients of an atmospheric organic amine, comprising the following steps:

[0011] S1. Prepare an organic amine solution;

[0012] S2. using an integrated aerosol generator to atomize the organic amine solution into an organic amine aerosol, and drying;

[0013] S3. Using a scanning mobility particle size spectrometer to detect the particle size distribution and total mass concentration of organic amine particles;

[0014] S4. Use the real-time analysis and injection system of aerosol chemical composition to couple the proton transfer reaction time-of-flight mass spectrometer, and detect the concentration of organic amine in the particle phase and the concentration of organic amine in the gas phase respectively by switching the software;

[0015] S5. The particle phase concentration of the organic amine is divided by the product of the gas phase concentration and the total particle mass concentration to obtain the distribution coefficient of the organic amine;

[0016] Wherein, the concentration of the organic amine solution in step S1 is 3 to 10 M;

[0017] The parameters of the aerosol chemical composition real-time analysis sampling system in step S4 are set as follows: the thermal decomposition temperature is 60-180°C.

[0018] The present invention obtains organic amine aerosol through an integrated aerosol generator, detects the mass concentration of total nano aerosol particles by a scanning mobility particle size spectrometer, and then simultaneously detects the organic amine concentrations in the gas phase and particle phase by coupling a proton transfer reaction time-of-flight mass spectrometer with an aerosol chemical composition real-time analysis sampling system, and calculates the distribution coefficient. The present invention innovatively proposes a method for obtaining an aerosol by directly passing an organic amine solution into an integrated aerosol generator. The present invention sets a concentration range for the organic amine solution entering the integrated aerosol generator, and the concentration must be above 3M; at the same time, the detection instrument also has requirements for the detection limit of the organic amine, that is, the lower limit of the concentration. Too low a concentration of the organic amine may result in a weak detection signal that cannot reach the detection limit of the detector. The concentration cannot exceed 10M, and too high a concentration will exceed the detection range of the instrument.

[0019] When setting the parameters of the real-time analysis and injection system of aerosol chemical composition coupled to the proton transfer reaction time-of-flight mass spectrometer, the key parameter is the thermal desorption temperature. The principle of setting the thermal desorption temperature range of organic amines involves the volatility, thermal stability and detection efficiency of the instrument. Too high a temperature will destroy the organic amines and reduce the measured concentration. Controlling the temperature range can make all the organic amines in the particulate matter evaporate, ensuring the accuracy of the measurement and preventing the organic amines from being destroyed by high temperature. When the temperature is below 60°C, the thermal motion of the organic amine molecules slows down, resulting in a decrease in the probability of their transfer from the particle phase to the gas phase. This will reduce the amount of organic amines volatilized, weakening the detection signal, thereby affecting the sensitivity and accuracy of the detection.

[0020] The organic amine solution in step S1 is any one of the organic amines in the prior art.

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

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

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

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

[0025] Specifically, the drying step in step S2 includes: firstly, generating a two-hour aerosol sample through a Teflon tube and entering a waste gas bag for collection, so as to ensure that the Teflon tube has reached the particle absorption-release equilibrium on the tube wall before sampling.

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

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

[0028] Specifically, the scanning mobility particle size spectrometer includes an electrostatic classifier, a differential mobility analyzer, and a condensation nucleus particle counter, wherein the electrostatic classifier includes a single-stage inertial impactor and a radioactive neutralizer.

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

[0030] Specifically, the aerosol chemical composition real-time online analysis sampling 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 sampling system in step S4 are set to: 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 sampling system in step S4 are set as follows: the analysis temperature is 60-180°C, the pressure of the drift tube is 2.3 bar, the temperature is 120°C, and the energy level E / N value is 60-150TD, where E is the electric field strength, and its unit is 1TD=10 -17 v cm 2 , N is the number density of neutral gas.

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

[0034] Preferably, the parameters of the gas-proton transfer time-of-flight mass spectrometer in step S4 are set as follows: the pressure of the drift tube is 2.9 bar, the temperature is 120° C., and the energy level E / N value is 60 to 150 TD, where E is the electric field strength, and its unit is 1 TD=10 - 17 vcm 2 , N is the number density of neutral gas.

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

[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, an aerosol chemical composition real-time analysis sampling system, a proton transfer reaction time-of-flight mass spectrometer, and a scanning electron mobility particle size spectrometer.

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

[0038] The aerosol generator generates organic amine aerosol samples at a certain flow rate, and the nozzle is connected to a Nafion dryer for drying. First, it passes through a scanning mobility particle size spectrometer to detect the particle size distribution and total mass concentration of the organic amine particles. Then it enters the aerosol chemical composition real-time analysis sampling system, where the gas phase stripper efficiently adsorbs organic gases and transmits particles. Subsequently, the particles are enriched by an aerodynamic lens, and then the thermal desorber volatilizes the organic components in the particles into the gas phase. Finally, these organics are detected by proton transfer reaction time-of-flight mass spectrometry, and excess gas is discharged into the waste gas bag through the connected three-way valve; a PFA particle filter is required to remove particulate matter from the gas phase organic amine before it enters the instrument for detection; the aerosol chemical composition real-time analysis sampling system is coupled to the proton transfer reaction time-of-flight mass spectrometer to adjust the instrument parameters for gas phase and particle phase organic amine concentration detection through software switching.

[0039] The step of measuring the concentration of the organic amine in the particle phase and the concentration of the organic amine in the gas phase in step S4 includes two parts, namely, detecting the concentration of the organic amine in the gas phase and detecting the concentration of the organic amine in the particle phase.

[0040] Detecting gas-phase organic amine concentrations: Using H3O for proton transfer time-of-flight mass spectrometry + As an ion source, the proton affinity of organic amines is greater than that of water. The gas phase organic amines react with H3O + Proton transfer reaction occurs, and the ion signal of the corresponding organic amine can be detected. Detection of particle phase organic amine concentration: For real-time analysis of aerosol chemical composition, the gas phase stripper in the sampling system removes the gas phase organic amine, and the organic amine in the particles is volatilized into gas using a thermal desorption device, and then enters the proton transfer time-of-flight mass spectrometer to detect its concentration.

[0041] Specifically, the concentration data of the organic amine gas phase and particle phase in step S4 are analyzed as follows: each sample reaches a peak value and remains stable, and according to the curves indicated by different organic amines in the sample, the corresponding concentration value is obtained by taking the average value from the rising to the stable section. The measured organic amine gas phase and particle phase concentration signal values ​​are replaced by the drawn 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 protection scope of the present invention.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] The present invention provides a method for measuring the gas-liquid and gas-liquid-solid distribution coefficients of atmospheric organic amines. An integrated aerosol generator is used to generate organic amine aerosols, and the gas-phase and particle-phase concentrations of the organic amines and the mass concentration of total particulate matter are measured. The gas-liquid and gas-liquid-solid distribution coefficients of different organic amines are calculated. The method can be applied to the quantitative analysis of various organic amines in gas-phase and particle-phase samples in an atmospheric environment, has the characteristics of simple operation, and can provide important technical support for obtaining the distribution detection and evaluation of organic amines in an atmospheric environment. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0046] Figure 2 This is a graph showing the concentration of organic amines in the gas phase and particle phase in the cyclohexylamine aerosol sample in Example 2.

[0047] Figure 3 This is a distribution diagram of the mass concentration of the nanoparticle phase in the cyclohexylamine aerosol sample in Example 2. DETAILED DESCRIPTION

[0048] In order to more clearly and completely describe the technical solution of the present invention, the present invention is further described in detail through specific embodiments below. It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention. Various changes can be made within the scope of the rights of the present invention.

[0049] Unless otherwise specified, the 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 30mL of dimethylamine sample aqueous solution into a sampling bottle, turn on the aerosol generator switch, set the aerosol generation flow rate to 1.5L / min, generate dimethylamine aerosol at the nozzle, and then dry it with a Nafion drying tube. At room temperature (25±2℃), the relative humidity is maintained at 35±5%.

[0053] 3. Before the aerosol samples are collected and tested, they are first collected into the waste gas bag through the Teflon tube for 2 hours to ensure the adsorption-release equilibrium of particles on the Teflon tube wall. Before each sample is introduced into the aerosol chemical composition online real-time analysis sampling system coupled with the proton transfer time-of-flight mass spectrometer, nitrogen is first passed for 30 minutes to clean the residue in the instrument and the signal value after cleaning is used as blank data.

[0054] 4. The aerosol generator atomizes the dimethylamine aqueous solution to produce an aerosol sample, which enters the Nafion drying tube through a Teflon tube for drying, and then enters the scanning mobility particle size spectrometer (SMPS) through a three-way valve to detect the total mass concentration of nanoparticles. The other part enters the aerosol chemical composition real-time analysis sampling system (CHARON), and the gas phase stripper efficiently adsorbs the dimethylamine gas and transmits the nanoparticles. The aerodynamic lens then enriches these particles, and then the thermal analysis system converts the particle phase dimethylamine into the gas phase. Finally, the proton transfer reaction time-of-flight mass spectrometry uses hydronium ions to detect the gas phase dimethylamine by soft ionization, and then draws a mass spectrum and transmits it to the computer display. The remaining samples enter the waste gas bag through a three-way valve for collection. The residual particles in the connecting pipe are rinsed clean with high-purity N2 that does not contain particles, and then the next sample is tested.

[0055] 5. Based on the exploration, the optimal parameters are: the thermal desorption temperature of the aerosol chemical composition online real-time analysis injection system is 150°C, 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 intensity, and its unit is 1TD=10 -17 v cm 2 , N is the number density of neutral gas), the detection time is 1 to 10 min. The sheath gas flow rate of the scanning mobility particle size spectrometer is 3 L / min, the sampling flow rate is 0.3 L / min, and the scanning time is 392 to 1000 s.

[0056] 6. In this embodiment, dimethylamine aerosol is selected for generation and gas-particle phase concentration detection. The gas-phase dimethylamine detection method is to use an aerosol generator to generate dimethylamine pure water aerosol, and the generation flow rate of the aerosol generator is 1.5L / min. The aerosol enters the Nafion drying tube through a Teflon tube for drying, and then the particles are intercepted on the filter membrane through a PFA particle filter. A part of the gas-phase dimethylamine enters the proton transfer time-of-flight mass spectrometer (PTR-ToF-MS) through a three-way valve for detection, and the other part is discharged as residual gas and collected using a waste gas bag.

[0057] 7. Based on the exploration, the optimal parameters are: the pressure of the drift tube of the proton transfer time-of-flight mass spectrometer is 2.9 bar, the energy level (E / N) of the drift tube is 145TD (E is the electric field strength, and its unit is 1TD=10 -17 v cm 2 , N is the number density of neutral gas). The detection time is 1 to 10 minutes.

[0058] 8. This example uses a dimethylamine permeation tube system to calibrate a proton transfer time-of-flight mass spectrometer. The standard gas produced by the permeation tube is diluted with high-purity nitrogen gas, a concentration gradient is set, and a standard curve is drawn. Figure 1 The schematic diagram of the structure of the method for measuring the distribution coefficient of organic amine on particles of the present invention includes an integrated aerosol generator, a Nafion drying tube, a PFA particle filter, a three-way valve, an exhaust bag, a proton transfer time-of-flight mass spectrometer (PTR-ToF-MS), an aerosol chemical composition real-time analysis sampling system (CHARON), and a scanning mobility particle size spectrometer (SMPS); the distribution coefficient formula is: K P =C p / (C g ×TSP), where C p and C g are the concentrations of organic compounds in the particle phase and gas phase, respectively (μg m -3 ), TSP here refers to the mass concentration of total nanoaerosol particles (μg m -3 ). The gas-particle phase signal value was replaced by the value on the standard curve, and the distribution 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 test substance in the parameter setting of this example is cyclohexylamine. The test results show that 406 μL of 99.5% cyclohexylamine solution is taken to a 500 mL brown volumetric flask to make up to volume to prepare a 3.0 M cyclohexylamine sample aqueous solution.

[0061] 2. Take 40mL of cyclohexylamine sample aqueous solution into the sampling bottle, and the flow rate of the aerosol generator is 1.5L / min. The aerosol chemical composition online real-time analysis sampling system is coupled with the proton transfer flight time mass spectrometer. According to the curve indicated by the cyclohexylamine ((C6H13N)H+m / z 100.170) of the sample, the average value is selected from the rising to the stable section to obtain the corresponding concentration value, and the detection time is 50-180s. The scanning time of the scanning mobility particle size spectrometer is 392s.

[0062] 3. The signal value of cyclohexylamine in the gas-particle phase is replaced by the value on the standard curve. The calculation results show that the distribution coefficient of cyclohexylamine in pure water aerosol is (3.0±0.81)×10 -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 setting of this embodiment is 4.2 M, that is, 700 μL of 40% dimethylamine solution by mass is taken into a 500 mL brown volumetric flask to make up to volume to prepare the dimethylamine sample aqueous solution.

[0065] 2. Take 50mL of dimethylamine sample aqueous solution into the sampling bottle. The flow rate of the aerosol generator is 1.5L / min. The aerosol chemical composition online real-time analysis injection system is coupled with the proton transfer flight time mass spectrometer. According to the curve indicated by the dimethylamine ((C2H7N)H+m / z 46.065) of the sample, the average value is selected from the rising to the stable section to obtain the corresponding concentration value. The detection time is 70 to 90s. The scanning time of the scanning mobility particle size spectrometer is 392s.

[0066] 3. The gas-particle phase signal value of dimethylamine is replaced by the value on the standard curve. The calculation results show that the distribution coefficient of dimethylamine in water aerosol is (2.0±0.42)×10 -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 setting of this embodiment is 2 L / min.

[0069] 2. Take 50mL of dimethylamine sample aqueous solution into the sampling bottle, and the flow rate of the aerosol generator is 2L / min. The online real-time analysis of the chemical composition of the aerosol is coupled to the proton transfer time-of-flight mass spectrometer. The flow rate of the dimethylamine aerosol generator is 2L / min. According to the curve indicated by the dimethylamine ((C2H7N)H+m / z 46.065) of the sample, the average value is selected from the rising to the stable section to obtain the corresponding concentration value, and the detection time is 50-70s. The scanning time of the scanning mobility particle size spectrometer is 588s.

[0070] 3. The gas-particle phase signal value of dimethylamine is replaced by the value on the standard curve. The calculation results show that the distribution coefficient of dimethylamine in water aerosol is (1.4±0.77)×10 -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 the parameter setting of this embodiment is a dimethylamine hydrochloride aqueous solution. The test results show that 0.237g of dimethylamine hydrochloride solid is weighed and fixed to volume in a 500mL brown volumetric flask to prepare a 3.0M dimethylamine hydrochloride sample aqueous solution.

[0073] 2. Take 50mL of dimethylamine sample aqueous solution in a sampling bottle, and the flow rate of the aerosol generator is 1.5L / min. The aerosol chemical composition online real-time analysis sampling system is coupled with a proton transfer flight time mass spectrometer. According to the curve indicated by the dimethylamine ((C2H7N)H+m / z 46.065) of the sample, the average value is selected to obtain the corresponding concentration value when it rises to the stable section. The detection time is 50-70s. The scanning time of the scanning mobility particle size spectrometer is 588s.

[0074] 3. The gas-particle phase signal value of dimethylamine is replaced by the value on the standard curve. The calculation results show that the distribution coefficient of dimethylamine in water-ammonium chloride salt aerosol is (1.4±0.21)×10 -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 the parameter setting of this example is a 3.0M dimethylamine sodium chloride aqueous solution. The test results show that 500 μL of a 40% dimethylamine solution and 4 g of NaCl solid are weighed and fixed to volume in a 500 mL brown volumetric flask to prepare a dimethylamine sodium chloride sample aqueous solution.

[0077] 2. Take 45mL of sample solution in a sampling bottle, and the flow rate of the aerosol generator is 2.5L / min. The online real-time analysis of the chemical composition of the aerosol is coupled to the proton transfer time-of-flight mass spectrometer. According to the curve indicated by the dimethylamine ((C2H7N)H+m / z46.00) of the sample, the average value is selected from the rising to the stable section to obtain the corresponding concentration value, and the detection time is 80-100s. The scanning time of the scanning mobility particle size spectrometer is 392s.

[0078] 3. The gas-particle phase signal value of dimethylamine is replaced by the value on the standard curve. The calculation results show that the distribution coefficient of dimethylamine in inorganic salt-water aerosol is (3.5±0.40)×10 -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 setting of this example is a real atmospheric sample of a contaminated site. The research results show that the ambient atmosphere is collected in a Teflon air bag by vacuum pumping at the contaminated site.

[0081] 2. The atmospheric samples collected in the air bag were passed through the aerosol chemical composition online real-time analysis sampling system coupled with the proton transfer flight time mass spectrometer, and the gas phase and particle phase concentrations of organic amines were measured by software switching. According to the curve indicated by the dimethylamine ((C2H7N)H+m / z 46.065) of the sample, the corresponding concentration value was obtained by averaging the rising to stable section, and the detection time was 70 to 130 seconds. The scanning time of the scanning mobility particle size spectrometer was 392 seconds.

[0082] 3. The gas-particle phase signal value of dimethylamine is replaced by the value on the standard curve. The calculation results show that the distribution coefficient of dimethylamine in the 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 that of Example 1, except that the concentration of the dimethylamine solution in step 1 is 2 M, and the concentration of the particle phase is lower than the detection limit and 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 that of Example 1, except that the concentration of the dimethylamine solution in step 1 is 11 M, and the gas phase concentration of the organic amine is too high and exceeds 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 that of Example 1, except that the thermal desorption temperature of the aerosol chemical composition online real-time analysis sampling system in step 5 is 50°C.

[0089] The distribution coefficient of dimethylamine in water aerosol is (1.5±0.36)×10 -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 that of Example 1, except that the thermal desorption temperature of the aerosol chemical composition online real-time analysis sampling system in step 5 is 180°C.

[0092] The distribution coefficient of dimethylamine in water aerosol is (5.8±0.21)×10 -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 to 11 achieve rapid and convenient measurement of the gas phase and particle phase of organic amines, among which Example 1 is the best measurement method.

[0094] In comparative example 1, the organic amine concentration is set to be less than the range, and the particle phase concentration is lower than the detection limit and cannot be measured; in comparative example 2, the organic amine concentration is greater than the range, and the gas phase concentration of the organic amine is too high, exceeding the detection range of the instrument; in comparative example 3, the thermal decomposition temperature of the online real-time analysis injection system of the chemical composition of the aerosol is set to be less than the range, indicating that the thermal decomposition temperature is small, which will reduce the volatilization amount of the organic amine and weaken the detection signal, thereby affecting the sensitivity and accuracy of the detection; in comparative example 4, the thermal decomposition temperature is set to be greater than the range, and the obtained distribution coefficient will be reduced, which will destroy the organic amine and make the measurement result 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 embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope 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: The following steps are involved: S1. Prepare an organic amine solution; S2. using an integrated aerosol generator to atomize the organic amine solution into an organic amine aerosol, and drying; S3. Using a scanning mobility particle size spectrometer to detect the particle size distribution and total mass concentration of organic amine particles; S4. Use the real-time analysis and injection system of aerosol chemical composition to couple the proton transfer reaction time-of-flight mass spectrometer, and detect the concentration of organic amine in the particle phase and the concentration of organic amine in the gas phase respectively by switching the software; S5. The particle phase concentration of the organic amine is divided by the product of the gas phase concentration and the total particle mass concentration to obtain the distribution coefficient of the organic amine; Wherein, the concentration of the organic amine solution in step S1 is 3 to 10 M; The parameters of the aerosol chemical composition real-time analysis sampling system in step S4 are set as follows: the thermal decomposition temperature is 60-180°C.

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

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

4. The method according to claim 1, characterized in that: The drying step in step S2 includes: firstly, generating a two-hour aerosol sample through a Teflon tube and entering a waste gas bag for collection, so as to ensure that the Teflon tube has reached a particle 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 gas flow rate is 3 L / min, sampling flow rate is 0.3 L / min, and scanning time is 392 to 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 to: an energy level E / N value of 60 to 150TD.

7. The method according to claim 1, characterized in that The step of measuring the concentration of the organic amine in the particle phase and the concentration of the organic amine in the gas phase in step S4 includes two parts, namely, detecting the concentration of the organic amine in the gas phase and detecting the concentration of the organic amine in the particle phase.

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, an aerosol chemical composition real-time analysis sampling system, a proton transfer reaction time-of-flight mass spectrometer, and a scanning mobility particle size spectrometer.

9. The system of the method for measuring the gas-liquid and gas-liquid-solid partition coefficients of atmospheric organic amines according to claim 8, characterized in that: The following implementations are included: The aerosol generator generates organic amine aerosol samples at a certain flow rate, and the nozzle is connected to a Nafion dryer for drying. First, it passes through a scanning mobility particle size spectrometer to detect the particle size distribution and total mass concentration of the organic amine particles. Then it enters the aerosol chemical composition real-time analysis sampling system, where the gas phase stripper efficiently adsorbs organic gases and transmits particles. Subsequently, the particles are enriched by an aerodynamic lens, and then the thermal desorber volatilizes the organic components in the particles into the gas phase. Finally, these organics are detected by proton transfer reaction time-of-flight mass spectrometry, and excess gas is discharged into the waste gas bag through the connected three-way valve; a PFA particle filter is required to remove particulate matter from the gas phase organic amine before it enters the instrument for detection; the aerosol chemical composition real-time analysis sampling system is coupled to the proton transfer reaction time-of-flight mass spectrometer to adjust the instrument parameters for gas phase and particle phase organic amine concentration detection through software switching.

10. Use of the 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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