Detection method for volatile methylsiloxane in microenvironment air, acquisition equipment and application of detection method and acquisition equipment

Abstract

The invention relates to the technical field of environment monitoring, and discloses a detection method and collection equipment for volatile methylsiloxane in microenvironment air and application of the detection method and collection equipment. According to the equipment disclosed by the invention, a solid-phase extraction column, an adapter, a connecting pipe and a sampling pump are connected in sequence; a sieve plate for supporting the filler and preventing the filler from escaping is arranged in the solid-phase extraction column; a filler of the solid-phase extraction column is a modified polystyrene-divinyl benzene copolymer, and the surface of the filler is modified by 0.5-10wt% of non-ionizable hydroxyl. According to the invention, simultaneous sampling and efficient detection of as many as 13 components of cyclic and chain siloxane (D4-D9, L3-L9) are realized; the adsorption and elution efficiency is remarkably improved, complete desorption can be realized only by about 2.0 mL of eluent, and the dosage of an organic solvent is reduced; the method can maintain high recovery rate and repeatability, and is suitable for rapid and sensitive detection of siloxane in indoor microenvironment air.

Description

Technical Field

[0001] This invention relates to the field of environmental monitoring technology, and more specifically, to a method, collection equipment, and application for detecting volatile methylsiloxanes in microenvironmental air. Background Technology

[0002] Volatile methylsiloxanes (VMS) are a class of synthetic compounds composed of a silicon-oxygen backbone and methyl groups. They are classified into cyclic (cVMS) and chain (lVMS) types, with common examples including octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), dodecylcyclohexasiloxane (D6), octamethyltrisiloxane (L3), decamethyltetrasiloxane (L4), and dodecylpentasiloxane (L5). VMS exhibit high stability, low reactivity, and low viscosity, and are widely used in personal care products, lubricants, defoamers, and silicone production. However, their high volatility leads to easy accumulation in indoor air, with concentrations often higher than in outdoor environments, and they can even migrate over long distances, posing potential risks of persistence and bioaccumulation. To control their environmental and health impacts, the European Union has included D4–D6, L3, and L4 in its List of Substances of Very High Concern and has strengthened restrictions and regulations on their production and emissions.

[0003] With the increasing demand for VMS detection and analysis in the air, traditional air sampling, which uses a sampling pump to control the air flow, can obtain high temporal resolution concentration data in a short time, making it more suitable for detecting high concentrations of VMS in indoor microenvironment air.

[0004] However, existing active sampling devices still have certain limitations in terms of adsorbent material selection and equipment structure. For example, some adsorbent materials have high background pollution, require cumbersome cleaning and post-treatment processes, and the overall device size is large and inconvenient to carry. Among the main adsorbent materials currently used for VMS sampling in the air, polyurethane foam (PUF) requires a large amount of solvent extraction and rotary evaporation, which is complex to operate and prone to introducing secondary pollution; while the glass-sealed structure of XAD adsorbent resin tubes requires multiple cuttings and is not convenient for pre-cleaning. The application of SPE columns has improved the ease of operation and background control to some extent, but due to the volatility and loss of VMS, the selection of SPE column packing remains crucial.

[0005] Existing literature reports methods for sampling and analyzing some VMS in the air using ABN adsorption columns. However, these sampling devices are mainly designed for outdoor ambient air, have long sampling cycles and large volumes, making them inconvenient to deploy in limited indoor spaces. They can detect a limited number of VMS types, making it difficult to reflect the distribution characteristics of different VMS forms. At the same time, their applicability under high concentration or short-time sampling conditions is still insufficient, limiting their widespread application in indoor microenvironment monitoring. Summary of the Invention

[0006] To overcome the shortcomings of the prior art in the detection of volatile methylsiloxanes in indoor microenvironments, such as high background pollution of adsorbent materials, low sampling efficiency, and limited detection of multiple components, this invention provides a method for detecting volatile methylsiloxanes in microenvironment air. Another object of the present invention is to provide a device for collecting volatile methylsiloxanes in the air of a microenvironment; Another object of the present invention is to provide an application of a device for collecting volatile methylsiloxanes in microenvironment air.

[0007] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows: A method for detecting volatile methylsiloxanes in microenvironmental air, comprising sampling using a microenvironmental air volatile methylsiloxane collection device, including the following steps: S1. Place the VMS (Very Microenvironmental Monitoring System) acquisition device in the environment to be tested; S2. Start the sampling pump to collect samples; S3. Load the solid phase extraction column onto the extraction apparatus and add eluent to elute; S4. After adding the internal standard solution, VMS is detected by GC-MS / MS.

[0008] Preferably, the solid-phase extraction column is used after pre-cleaning, which includes the following steps: loading the solid-phase extraction column onto the solid-phase extraction instrument and immersing it in n-hexane; then rinsing it sequentially with dichloromethane and n-hexane; drying it by vacuum pumping; wrapping it in aluminum foil and storing it in a -20 ℃ refrigerator until use.

[0009] Preferably, the operating parameters of GC-MS / MS are as follows: Chromatographic column: HP-5MS; 15 m × 250 μm × 0.25 μm × 2 (two columns in series); Carrier gas (He) flow rate: 1.0 mL / min for the first stage; 1.2 mL / min for the second stage; Temperature program: Hold at 40 ℃ for 2.0 min, increase to 220 ℃ at 20 ℃ / min, increase to 280 ℃ at 10 ℃ / min, hold for 5.0 min, then run at 300 ℃ and hold for 5.0 min; Injection volume: 1.0 μL; Injection method: splitless injection; purge flow rate to split outlet: 50 mL / min; purge time: 0.75 min. Inlet temperature: 250 ℃; Ion source: Electron impact ion source; Ionization energy: 70 eV; Ion source temperature: 280 ℃; Quadrupole mass analyzer temperature: 150 ℃; Transfer line temperature: 300 ℃; Solvent delay: 2.5 min; Detection method: Multiple reaction monitoring (MRM); Running time: hold for 22.0 min, then run for 5.0 min, then run at 300 ℃.

[0010] Furthermore, the flow rate of the sampling pump is set to 200~800 mL / min, and the sampling time is 0.5~1.0 h.

[0011] Preferably, the flow rate of the sampling pump is set to 200~500 mL / min, and the sampling time is 0.5~1.0 h.

[0012] Preferably, the sampling pump has a flow rate of 500 mL / min and a sampling time of 0.5 h.

[0013] Furthermore, the eluent is n-hexane, and the amount added is 0.5~2.0 mL.

[0014] Preferably, the eluent is n-hexane, and the amount added is 1.0~2.0 mL.

[0015] Preferably, the eluent is n-hexane, and the amount added is 2.0 mL.

[0016] A device for collecting volatile methylsiloxanes in a microenvironment comprises a solid-phase extraction column, an adapter, a connecting pipe, and a sampling pump connected in sequence; the solid-phase extraction column is provided with a sieve plate for supporting the packing material and preventing it from escaping; the packing material of the solid-phase extraction column is a modified polystyrene-divinylbenzene copolymer, the surface of which is modified with 0.5~10 wt% non-ionizable hydroxyl groups.

[0017] Furthermore, the filler has a particle size of 30~50 μm and a specific surface area ≥500 m². 2 / g.

[0018] Furthermore, the packing volume of the solid phase extraction column is 15~20 mg / mL.

[0019] Preferably, the packing amount of the solid phase extraction column is 20 mg / mL.

[0020] Furthermore, the volume of the solid-phase extraction column is 1.0~3.0 mL.

[0021] The solid-phase extraction column has a volume of 3.0 mL.

[0022] Furthermore, the VMS includes at least one of cyclic volatile methylsiloxanes and chain volatile methylsiloxanes.

[0023] Preferably, the cyclic VMS (cVMS) includes at least one of octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), dodecylmethylcyclohexasiloxane (D6), tetradecylmethylcycloheptasiloxane (D7), hexadecylmethylcyclooctasiloxane (D8), and octadecylmethylcyclononasiloxane (D9); Preferably, the chain-like VMS (lVMS) includes at least one of octamethyltrisiloxane (L3), decamethyltetrasiloxane (L4), dodecylpentasiloxane (L5), tetradecylhexasiloxane (L6), hexadecylheptasiloxane (L7), octadecyloctasiloxane (L8), and eicosylnonasiloxane (L9).

[0024] An application of the aforementioned device for detecting volatile methylsiloxanes in indoor microenvironment air, used for collecting air samples in indoor microenvironment.

[0025] Preferably, the indoor microenvironment includes vehicles, residences, offices, public leisure areas, and medical and scientific research facilities.

[0026] Furthermore, at least one of cVMS: octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), dodecylcyclohexasiloxane (D6), tetradecylcycloheptasiloxane (D7), hexadecylcyclooctasiloxane (D8), and octadecylcyclononasiloxane (D9); and at least one of lVMS: octamethyltrisiloxane (L3), decamethyltetrasiloxane (L4), dodecylpentasiloxane (L5), tetradecylhexasiloxane (L6), hexadecylheptasiloxane (L7), octadecyloctasiloxane (L8), and eicosylnonasiloxane (L9).

[0027] The adsorbent material selected in this invention uses polystyrene-divinylbenzene as its framework and incorporates non-ionized hydroxyl functional groups, possessing both hydrophilic and hydrophobic adsorption sites. It can stably adsorb siloxane components of different polarities under neutral conditions, effectively reducing background interference. Compared with traditional silica gel or ENV+ adsorbents, this material exhibits high adsorption selectivity and good repeatability, solving the problems of easy penetration of low-molecular-weight siloxanes and difficulty in desorption of high-molecular-weight components.

[0028] By limiting the volume and packing ratio of the solid-phase extraction column and matching the flow rate range of the sampling pump, a dynamic balance between adsorption capacity and gas contact time was established, ensuring that different components can be fully captured and eluted in a short time. The matching of these three factors produces a significant synergistic effect, which not only improves the overall detection sensitivity and repeatability but also makes the elution process more efficient, significantly reducing solvent usage and operation time.

[0029] Furthermore, this invention is the first to apply this system to indoor microenvironment air samples, enabling the simultaneous detection of up to 13 VMS, including cyclic D4-D9 and chain L3-L9, in a single sampling. This achieves accurate detection of multiple components under high concentration and short sampling conditions, overcoming the limitation of existing methods that are only applicable to ambient air or low-concentration samples.

[0030] Compared with the prior art, the beneficial effects of the technical solution of the present invention are: By employing a synergistic design of modified polystyrene-divinylbenzene copolymer as the adsorbent, a matched small-volume, high-specific-surface-area solid-phase extraction column, and a constant-flow sampling pump, this invention achieves simultaneous collection and efficient detection of up to 13 components in cyclic and chain-like VMS (D4–D9, L3–L9). This invention significantly improves adsorption and elution efficiency, requiring only approximately 2.0 mL of eluent for complete desorption, thus reducing the amount of organic solvent used. It maintains high recovery rates and repeatability at flow rates of 200–800 mL / min, making it suitable for rapid and sensitive detection of siloxanes in indoor microenvironments. Attached Figure Description

[0031] Figure 1 The structure and working principle of a VMS (Voice Monitoring System) acquisition device in a microenvironment. Detailed Implementation

[0032] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in this technical field.

[0033] Unless otherwise specified, all reagents and materials used in the following examples are commercially available.

[0034] In the following embodiments, the modified polystyrene-divinylbenzene copolymer (ABN) was purchased from Biotage, with its surface modified by 0.5-10 wt% non-ionizing hydroxyl groups, a particle size of 30-50 μm, and a specific surface area ≥500 m². 2 / g.

[0035] like Figure 1 As shown, the solid phase extraction column 1, adapter 2, connecting pipe 3 and sampling pump 4 are connected; the solid phase extraction column is provided with a sieve plate 6 for supporting the packing material 5 and preventing the packing material 5 from escaping, thus obtaining an indoor microenvironment air VMS collection device.

[0036] Example 1 1. Pretreatment: (1) Pre-cleaning of the solid-phase extraction column: The solid-phase extraction column (filled with 60 mg / 3 mL modified polystyrene-divinylbenzene copolymer) was loaded onto the solid-phase extraction instrument and soaked in n-hexane for 12.0 h, followed by rinsing with dichloromethane and n-hexane three times in sequence. After completion, the column was dried by vacuum pumping for 10.0 s. After drying, the column was wrapped in aluminum foil and sealed in a self-sealing bag and stored in a -20 ℃ refrigerator for sampling.

[0037] (2) Preparation of internal standard solution: Take 100.0 μL of tetra(trimethylsiloxy)silane (M4Q) with a concentration of 100 ppm stored in methanol and add it to methanol to prepare a 5 ppm internal standard solution.

[0038] 2. Sampling: Connect the pre-cleaned and thawed solid-phase extraction column, adapter, connecting tubing, and sampling pump in sequence, sealing all connections. Connect the other end of the solid-phase extraction column to the external sampling air and place it in the environment to be tested. Start the sampling pump to collect samples at a flow rate of 500 mL / min for 0.5 h. After sampling, wrap and seal the column with aluminum foil, label it, and store it in a -20 ℃ freezer.

[0039] 3. Elution: Load the solid-phase extraction column onto the solid-phase extraction instrument, pipette 2.0 mL of n-hexane into the column, and allow it to elute under gravity. Extract the remaining eluent using a vacuum pump, transfer 1.0 mL of the eluent to a chromatography vial, add 20.0 μL of 5 ppm internal standard solution, seal with aluminum foil, and seal with a cap without a septum for analysis.

[0040] 4. Detection and Analysis: Triple quadrupole gas chromatography-mass spectrometry (GC-MS) was used to detect and analyze siloxanes. The specific analytical parameters are as follows: Instrument model: Agilent 8890 gas chromatograph with Agilent 7000E mass spectrometer detector Injector: PAL RSI 85 autosampler Chromatographic column: HP-5MS; 15 m × 250 μm × 0.25 μm × 2 (two columns in series) Carrier gas (He) flow rate: 1.0 mL / min for the first stage; 1.2 mL / min for the second stage. Temperature program: Hold at 40 ℃ for 2.0 min, increase to 220 ℃ at 20 ℃ / min, increase to 280 ℃ at 10 ℃ / min, hold for 5.0 min, then run at 300 ℃ and hold for 5.0 min.

[0041] Injection volume: 1.0 μL.

[0042] Injection method: splitless injection; purge flow rate to split outlet: 50 mL / min; purge time: 0.75 min.

[0043] Inlet temperature: 250 ℃.

[0044] Ion source: electron impact ion source; ionization energy: 70 eV; ion source temperature: 280 ℃; quadrupole mass analyzer temperature: 150 ℃; transfer line temperature: 300 ℃; solvent delay: 2.5 min; detection method: multiple reaction monitoring.

[0045] Running time: hold for 22.0 min, then run for 5.0 min, then run at 300 ℃.

[0046] Table 1 Detection parameters

[0047] Example 2 The technical solution of Example 2 is similar to that of Example 1, except that the sampling pump flow rate is set to 200 mL / min.

[0048] Example 3

[0049] 1. Pretreatment: The steps are the same as in Example 1.

[0050] 2. Sampling: Connect the solid-phase extraction column, adapter, connecting tube, and sampling pump in sequence, sealing all connections. Connect the other end of the solid-phase extraction column to the external sampling air and place it in the environment to be tested. Start the sampling pump to collect samples at a flow rate of 200 mL / min for 1.0 h. After sampling, wrap the column in aluminum foil, label it, and store it in a -20 ℃ refrigerator.

[0051] 3. Elution: Load the solid-phase extraction column onto the solid-phase extraction instrument, pipette 2.0 mL of n-hexane into the column, and allow it to elute under gravity. Blow out the remaining eluent with a bubble tube, transfer 1.0 mL of the eluent to a chromatography vial, add 20.0 μL of 5 ppm internal standard solution, seal with aluminum foil, and seal with a cap without a septum for analysis.

[0052] 4. Detection and analysis: The steps are the same as in Example 1.

[0053] Comparative Example 1 The technical solution of Comparative Example 1 is similar to that of Example 1, except that the ABN column is replaced with an XAD-4 adsorption tube and an activated carbon column, respectively.

[0054] Comparative Example 2 The technical solution of Comparative Example 2 is similar to that of Example 1, except that the sampling pump flow rate is set to 1000 mL / min.

[0055] Comparative Example 3 1. Pretreatment: The steps are similar to those in Example 1, except that the solid phase extraction column (the packing material is 10 mg / 1 mL of modified polystyrene-divinylbenzene copolymer) is used.

[0056] 2. Sampling: Connect the solid-phase extraction column, adapter, connecting tube, and sampling pump in sequence, sealing all connections. Connect the other end of the solid-phase extraction column to the external sampling air and place it in the environment to be tested. Start the sampling pump to collect samples at a flow rate of 200 mL / min for 1.0 h. After sampling, wrap the column in aluminum foil, label it, and store it in a -20 ℃ refrigerator.

[0057] 3. Elution: Load the solid-phase extraction column onto the solid-phase extraction instrument, pipette 1.0 mL of n-hexane into the column, and allow it to elute under gravity. Extract the remaining eluent using a vacuum pump and directly transfer the eluent into a chromatography vial. Add 10.0 μL of 5 ppm internal standard solution, seal with aluminum foil, and then seal with a cap without a septum for analysis.

[0058] 4. Detection and analysis: The steps are the same as in Example 1.

[0059] Comparative Example 4 The technical solution of Comparative Example 4 is similar to that of Comparative Example 3, except that the sampling pump flow rate is set to 100 mL / min.

[0060] Comparative Example 5 The technical solution of Comparative Example 5 is similar to that of Comparative Example 3, except that the sampling pump flow rate is set to 250 mL / min.

[0061] Detection methods 1. Recovery rate experiment (1) Preparation of mixed standard solutions: D4, D5, D6, D7, D8, D9, L3, L4, L5, L6, L7, L8 and L9 standards stored in methanol at a concentration of 1000 ppm were diluted with methanol to 100 ppm respectively. Then, 100.0 μL of each standard solution with a concentration of 100 ppm was accurately pipetted and added to methanol to prepare a standard solution with a concentration of 5 ppm for each component.

[0062] (2) Sampling: Outdoor air with good air quality was selected as the control, and outdoor air samples were collected as the blank group. The experiment was conducted in an outdoor environment with good air quality. The recovery rate was evaluated by adding a certain amount of mixed standard solution during the outdoor air collection process and then eluting and recovering the solution. At the beginning of sampling, a 5 ppm mixed standard solution was drawn up using a microsyringe. At the same time interval, 5.0 μL of the mixed standard solution was added four times, for a total of 20.0 μL. After collection, the columns were sealed with aluminum foil, labeled, and stored in a -20 ℃ refrigerator as soon as possible for elution.

[0063] (3) Calculation of recovery rate The recovery rate (%) is obtained by dividing the concentration eluted from the solid-phase extraction column by the concentration of the standard solution.

[0064] 3. Detection of Siloxane Content in Column Background Background VMS content was determined in outdoor environments with good air quality using XAD-4, activated carbon, and solid-phase extraction columns (as described in Example 1). All three adsorption columns were connected to a sampling pump and placed in an outdoor environment with good air quality for air sampling. The flow rate was set at 250 mL / min, and the sampling time was 1.0 h.

[0065] 4. Application Example 1 was placed in a car for sampling to detect the VMS concentration in the cabin air.

[0066] Results Analysis In Tables 2-8, the acceptable range for recovery rate is 70% to 130%.

[0067] Table 2 Recovery rate of Example 1 lVMS L3 L4 L5 L6 L7 L8 L9 Recovery rate 90.4% 87.9% 93.1% 91.4% 89.1% 86.0% 83.2% cVMS D4 D5 D6 D7 D8 D9 Recovery rate 88.6% 89.6% 94.6% 91.5% 90.2% 86.8% Table 3 Recovery rate of Example 2 lVMS L3 L4 L5 L6 L7 L8 L9 Recovery rate 91.4% 90.1% 87.5% 85.6% 85.0% 86.8% 88.1% cVMS D4 D5 D6 D7 D8 D9 Recovery rate 80.1% 82.1% 82.7% 81.9% 81.9% 82.6% Table 4 Recovery rate of Example 3 lVMS L3 L4 L5 L6 L7 L8 L9 Recovery rate 116.4% 109.8% 108.5% 104.8% 98.7% 100.1% 93.7% cVMS D4 D5 D6 D7 D8 D9 Recovery rate 126.1% 107.1% 110.9% 108.6% 98.2% 97.1% Table 5 Recovery rate of Comparative Example 2 lVMS L3 L4 L5 L6 L7 L8 L9 Recovery rate 108.3% 103.7% 107.6% 103.6% 111.8% 115.7% 107.0% cVMS D4 D5 D6 D7 D8 D9 Recovery rate 150.5% 122.7% 133.8% 89.0% 112.3% 124.4% Table 6 Recovery rate of Comparative Example 3 lVMS L3 L4 L5 L6 L7 L8 L9 Recovery rate 23.8% 65.5% 98.7% 112.4% 118.0% 114.6% 120.7% cVMS D4 D5 D6 D7 D8 D9 Recovery rate 53.3% 75.7% 96.3% 104.2% 110.0% 120.7% Table 7 Recovery rate of Comparative Example 4 lVMS L3 L4 L5 L6 L7 L8 L9 Recovery rate 43.2% 77.2% 98.5% 102.0% 101.8% 97.8% 92.5% cVMS D4 D5 D6 D7 D8 D9 Recovery rate 68.1% 87.0% 91.3% 94.7% 97.7% 98.3% Table 8 Recovery rate of Comparative Example 5 lVMS L3 L4 L5 L6 L7 L8 L9 Recovery rate 12.7% 38.7% 35.4% 44.0% 48.7% 145.5% 77.3% cVMS D4 D5 D6 D7 D8 D9 Recovery rate 28.9% 34.7% 40.2% 40.6% 42.0% 67.6% 1. Impact on recovery rate (1) Influence of packing specifications In addition, the overall recovery rate of the 10 mg / 1 mL solid phase extraction column was poor. Due to the insufficient adsorption capacity of the packing, siloxanes could penetrate the adsorption packing during continuous air collection. In particular, siloxanes with smaller molecular weights are more volatile and more likely to escape from the adsorption packing.

[0068] (2) The influence of sampling pump flow rate and sampling time Comparative Examples 2 and 6, using a larger sampling flow rate (1000 mL / min) and an extended sampling time to 1.0 h, respectively, both resulted in a relative increase in recovery rate. High flow rate and extended sampling time may both induce the co-enrichment of other volatile components in the air matrix under a fixed column packing density, thus producing a matrix enhancement effect and leading to a higher detection signal. These phenomena indicate that the sampling flow rate and sampling time must be coordinated with the volume and packing density of the solid-phase extraction column; otherwise, abnormal adsorption and elution behavior may occur, affecting the accuracy of the quantitative results.

[0069] (3) The influence of column background siloxanes The XAD-4 and activated carbon columns in Comparative Example 1 could not be pre-cleaned, resulting in the inability to remove their high cVMS background (Table 9). In addition, the subsequent elution treatment steps for the two columns in Comparative Example 1 were cumbersome and prone to introducing secondary pollution.

[0070] Table 9. Column background siloxane concentration (ppb)

[0071] (4) Synergistic effect In this invention, a significant synergistic effect is achieved between the packing type, packing specifications, sampling flow rate, and sampling time. The use of ABN adsorbent material modified with non-ionizing hydroxyl groups gives the adsorption sites both hydrophilic and hydrophobic properties, enabling stable capture of siloxane components with significant polarity differences. A packing density of 10–20 mg / mL and a column volume of 1–3 mL balance the adsorption capacity with gas flow resistance. A constant flow sampling pump with a flow rate controlled at 200–800 mL / min and a sampling time of 0.5–1.0 h ensures sufficient contact time for the sample gas within the column while avoiding the breakthrough of low molecular weight components due to high flow rates or insufficient enrichment at low flow rates. This synergistic effect allows for efficient adsorption and complete elution of each component within a short time, with a stable recovery rate of 70%–130%, significantly improving overall detection sensitivity and repeatability.

[0072] 3. Effect of the amount of eluent added Elution was performed on the solid-phase extraction column of Example 1, with 20 μL of a 5 ppm mixed standard solution added. 0.5 mL of eluent was added each time, and the recovery rate for a single elution was calculated. The results are shown in Table 10.

[0073] Table 10 Single-cycle elution recovery rate

[0074] The first elution had the highest recovery rate, accounting for the majority of the total recovery. The recovery rate of the second elution decreased significantly, while the target analyte was almost undetectable in the third and subsequent elutions, indicating that a maximum of 2.0 mL of elution per elution was sufficient to achieve the desired elution effect.

[0075] 4. Application Air samples were collected from the cabins of 106 electric vehicles at an electric vehicle charging station. The air sampling device was placed on the right armrest of the driver's seat, and the sampling flow rate was set to 500 mL / min. The sampling time was 0.5 h. After collection, the solid phase extraction column was wrapped in aluminum foil and sealed and transported back to the laboratory for analysis. The siloxane concentration data in the cabin are shown in Table 11.

[0076] Table 11. Found characteristics of 13 VMS in the cabin air of new energy vehicles (ng / m³) 3 )

[0077] 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 can make other variations or modifications 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 device for collecting volatile methylsiloxanes in a microenvironment, characterized in that, The solid phase extraction column (1), adapter (2), connecting pipe (3) and sampling pump (4) are connected in sequence; the solid phase extraction column is provided with a sieve plate (6) for supporting the packing material (5) and preventing the packing material (5) from escaping; the packing material (5) of the solid phase extraction column (1) is a modified polystyrene-divinylbenzene copolymer, and the surface is modified with 0.5~10 wt% non-ionizable hydroxyl groups.

2. The device for collecting volatile methylsiloxanes in the microenvironment air according to claim 1, characterized in that, The filler (5) has a particle size of 30~50 μm and a specific surface area ≥500 m². 2 / g.

3. The device for collecting volatile methylsiloxanes in the microenvironment air according to claim 1, characterized in that, The packing amount of the solid phase extraction column (1) is 15~20 mg / mL.

4. The device for collecting volatile methylsiloxanes in the microenvironment air according to claim 1, characterized in that, The volume of the solid phase extraction column (1) is 1~3 mL.

5. The device for collecting volatile methylsiloxanes in the microenvironment air according to claim 1, characterized in that, The volatile methylsiloxanes include at least one of cyclic volatile methylsiloxanes and chain volatile methylsiloxanes.

6. A method for detecting volatile methylsiloxanes in microenvironment air, characterized in that, Sampling using the microenvironment air volatile methylsiloxane collection device according to any one of claims 1 to 5 includes the following steps: S1. Place the equipment for collecting volatile methylsiloxanes in the microenvironment air into the environment to be tested; S2. Start the sampling pump to collect samples; S3. After removing the solid-phase extraction column from the sampling device, load it onto the extractor and add eluent for elution. S4. After adding the internal standard solution, the volatile methylsiloxanes were detected by GC-MS / MS.

7. The method for detecting volatile methylsiloxanes in microenvironment air according to claim 6, characterized in that, The sampling pump has a flow rate of 200~800 mL / min and a sampling time of 0.5~1.0 h.

8. The method for detecting volatile methylsiloxanes in microenvironment air according to claim 6, characterized in that, The eluent is n-hexane, and the amount added is 0.5~2.0 mL.

9. An application of the microenvironment air volatile methylsiloxane collection device according to any one of claims 1 to 5, characterized in that, Used for the collection and detection of air samples in indoor microenvironments.

10. The application of the microenvironment air volatile methylsiloxane collection device according to claim 9, characterized in that, It can detect at least one of the following cyclic volatile methylsiloxanes: octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecylcyclohexasiloxane, tetradecylcycloheptasiloxane, hexadecylcyclooctasiloxane, and octadecylcyclononasiloxane; and at least one of the following chain volatile methylsiloxanes: octamethyltrisiloxane, decamethyltetrasiloxane, dodecylpentasiloxane, tetradecylhexasiloxane, hexadecylheptasiloxane, octadecyloctasiloxane, and icosylnonasiloxane.

Images