A method for enriching and detecting aromatic amine compounds in ambient air

Abstract

This invention belongs to the field of chemical detection technology, specifically relating to a method for enriching and detecting aromatic amine compounds in ambient air. The method for enriching aromatic amine compounds in ambient air provided by this invention includes the following steps: collecting ambient air samples using a glass fiber filter membrane, extracting with acid to obtain an extract, adjusting the extract to alkaline conditions, dispersing the extract in a diatomaceous earth solid-phase supported liquid-liquid extraction column, and eluting with n-hexane. By employing solid-phase supported liquid-liquid extraction technology with the extract under alkaline conditions, the alkaline conditions are conducive to the extraction of aromatic amine compounds by n-hexane, resulting in high extraction efficiency. This achieves a highly efficient, rapid, and high-throughput sample pretreatment process, is simple to operate, has higher throughput, and is more suitable for large-scale sample testing.

Description

Technical Field

[0001] This invention relates to the field of chemical detection technology, specifically to a method for enriching and detecting aromatic amine compounds in ambient air. Background Technology

[0002] Aromatic amines are amines with one aromatic substituent. They are widely found in the atmosphere, dyes, food and food contact materials, wastewater, leather, tobacco, and tobacco smoke. They are carcinogenic and mutagenic, and can cause poisoning through inhalation, ingestion, or skin absorption. Many aromatic amines are carcinogenic. The International Agency for Research on Cancer (IARC) classifies o-toluidine (o-TOL), 2-naphthylamine (2-NA), and 4-aminobiphenyl (4-ABP) as Group 1 carcinogens, 2,6-dimethylaniline (2,6-DMA) and o-methoxyaniline (o-ASD) as Group 2B carcinogens, and 1-naphthylamine (1-NA) as a Group 3 carcinogen.

[0003] Methods for detecting aromatic amines mainly include thin-layer chromatography (TLC), gas chromatography (GC), high-performance liquid chromatography (HPLC), gas chromatography-mass spectrometry (GC-MS), and liquid chromatography-tandem mass spectrometry (HPLC-MS / MS). Because HPLC-MS / MS does not require derivatization reactions, it offers higher sensitivity and selectivity, and since aromatic amines are present in low concentrations and are highly polar, it is a commonly used method for detecting aromatic amines.

[0004] However, ambient air samples are typically complex and contain extremely low levels of aromatic amines, necessitating sample enrichment and purification to reduce matrix effects in HPLC-MS / MS methods. Common sample pretreatment methods include liquid-liquid extraction, molecularly imprinted solid-phase extraction (SPE) column purification, and magnetic solid-phase extraction (MSE) based on magnetic COFs materials. Liquid-liquid extraction is cumbersome and uses large amounts of organic solvents, posing health risks to operators. Molecularly imprinted SPE offers high selectivity but has low adsorption capacity, and SPE columns are expensive. Magnetic solid-phase extraction based on magnetic COFs materials is not yet commercially available, making it unsuitable for large-scale sample testing.

[0005] Chinese patent application CN116754697A, published on September 15, 2023, discloses a method for enriching and detecting aromatic amine compounds in environmental flue gas, and a method for preparing sulfonic acid-functionalized organic materials. The method involves collecting environmental flue gas samples using a filter, extracting with hydrochloric acid solution, and then adding sulfonic acid-functionalized organic materials for solid-phase extraction to separate the solid phase. The solid phase is then eluted with an elution solvent. The sulfonic acid-functionalized organic material is a covalent triazine organic framework (CTF) synthesized from phthalonitrile and trifluoromethanesulfonic acid. The sulfonic acid groups of chlorosulfonic acid efficiently modify the covalent triazine organic framework (CTF-SO3H), enabling effective enrichment and purification of aromatic amine compounds in environmental flue gas samples. HPLC-MS / MS analysis was performed, and the detection limits for 1-aminonaphthalene, 2-aminonaphthalene, 3-aminobiphenyl, and 4-aminobiphenyl were 0.13, 0.16, 0.08, and 0.06, respectively. The limits of quantitation were 0.43, 0.53, 0.27, and 0.20 ng / mL, respectively.

[0006] The sulfonic acid-functionalized organic materials used in the above enrichment methods also suffer from low throughput, which cannot meet the requirements for large-scale sample testing. Summary of the Invention

[0007] The purpose of this invention is to provide a method for enriching aromatic amine compounds in ambient air, which solves the problem that existing methods for enriching aromatic amine compounds cannot simultaneously achieve simplicity, high adsorption capacity, and high throughput.

[0008] The second objective of this invention is to provide a method for detecting aromatic amine compounds in ambient air, thereby solving the problem of low detection efficiency in existing methods for detecting aromatic amine compounds.

[0009] To solve the above-mentioned technical problems, the technical solution of the enrichment method for aromatic amine compounds in ambient air of the present invention is as follows: A method for enriching aromatic amine compounds in ambient air includes the following steps: collecting ambient air samples using a glass fiber filter membrane, extracting with acid to obtain an extract, adjusting the extract to alkaline, dispersing the extract in a diatomaceous earth solid-phase supported liquid-liquid extraction column, and eluting with n-hexane.

[0010] This invention improves upon existing technology and provides a method for enriching aromatic amine compounds in ambient air. By employing solid-phase supported liquid-liquid extraction technology on an alkaline environment, the extract is distributed on the surface of diatomaceous earth in the form of a thin liquid film. Liquid-liquid extraction occurs immediately upon contact between the extract and n-hexane on the diatomaceous earth surface. The alkaline conditions are conducive to the extraction of aromatic amine compounds by n-hexane, resulting in high extraction efficiency.

[0011] The enrichment method provided by this invention achieves an efficient, rapid, and high-throughput sample pretreatment process. It is simple to operate, has higher throughput, and is more suitable for large-scale sample testing. Furthermore, the SLE solid-supported liquid-liquid extraction column used is a commercially available solid-phase extraction column, which is cheaper than molecularly imprinted solid-phase extraction columns, resulting in lower experimental costs.

[0012] To further improve the enrichment effect, preferably, the diatomaceous earth solid-phase supported liquid-liquid extraction column is ISOLUTE. ® SLE+.

[0013] To further ensure complete extraction of the target pollutant from the extract, preferably, 10-50 mL of n-hexane is added for every 5-20 mL of extract.

[0014] To further improve the extraction effect of n-hexane, preferably, the extract is adjusted to be alkaline by adding an alkaline solution, namely sodium hydroxide solution, to adjust the pH of the extract to 10-12.

[0015] To further improve the extraction efficiency of the target substance in the glass fiber filter membrane, preferably, the extraction is ultrasonic extraction, and the ultrasonic extraction time is 10~60 min.

[0016] To further improve the extraction efficiency of the target analyte in the glass fiber filter membrane, preferably, the acid solution is hydrochloric acid with a mass concentration of 5-10%.

[0017] To further improve the enrichment effect of the target analyte, preferably, the aromatic amine compound includes 1-aminonaphthalene, 2-aminonaphthalene, 3-aminobiphenyl, and 4-aminobiphenyl.

[0018] The technical solution of the method for detecting aromatic amine compounds in ambient air according to the present invention is as follows: A method for detecting aromatic amine compounds in ambient air, comprising enriching aromatic amine compounds in ambient air using the aforementioned enrichment method, followed by HPLC-MS / MS analysis.

[0019] The present invention provides a method for detecting aromatic amine compounds in ambient air. This method utilizes an enrichment method for aromatic amine compounds in ambient air, achieving a highly efficient, rapid, and high-throughput sample pretreatment process. It is simple to operate, has higher throughput, and is more suitable for large-scale sample testing. Using the detection method provided by this invention, the detection limit for aromatic amine compounds is 0.003~0.015 ng / mL, and the quantitation limit is 0.009~0.049 ng / mL.

[0020] To further improve the separation capability of aromatic amine compounds, the preferred chromatographic conditions for HPLC-MS / MS analysis are: Column: Waters Symmetry ShieldTM RP18; Column temperature: 30~40 o C; Injection volume: 10~15 μL; Pre-equilibration time: 10~15 min; Mobile phase A: 0.1 vol % formic acid-water solution, Mobile phase B: 0.1 vol % formic acid-acetonitrile solution; Gradient elution conditions: 0~3 min, 100% A; 3.1~17 min, 78% A; 17.1~22 min, 100% B; 22.1~33 min, 100% A.

[0021] To further improve detection accuracy, the preferred mass spectrometry conditions for HPLC-MS / MS analysis are as follows: ion source: electrospray ionization source; scanning mode: positive ion scan; detection mode: multiple reaction monitoring (MRM); electrospray voltage: 5500~6000 V; curtain gas pressure: 30~40 psi; auxiliary gas 1 pressure: 70~80 psi; auxiliary gas 2 pressure: 70~80 psi; ion source temperature: 500~550 °C. o C. Attached Figure Description

[0022] Figure 1 This is the MRM diagram of aromatic amine compounds in a typical ambient air sample from Example 1. Detailed Implementation

[0023] The technical concept of the method for enriching aromatic amine compounds in ambient air according to the present invention is as follows: Because environmental samples are complex and the content of target aromatic amine compounds is extremely low, sample enrichment is necessary. Existing enrichment methods include liquid-liquid extraction, which is complex and uses a large amount of solvent; molecularly imprinted solid-phase extraction columns have low adsorption capacity and high cost; and novel solid-phase extraction materials based on organic frameworks have poor enrichment effects and low throughput. This invention uses solid-phase supported liquid-liquid extraction technology to achieve rapid, effective, high-throughput, and low-cost enrichment by controlling the alkaline conditions and eluent during liquid-liquid extraction.

[0024] The method for enriching aromatic amine compounds in ambient air provided by the present invention includes the following steps: Ambient air samples were collected using glass fiber membranes at a flow rate of 5–15 L / min for 20–40 h. 10–200 mL of 5–10% HCl solution was added, and the mixture was ultrasonically extracted for 10–60 min. 5–20 mL of the extract was then accurately transferred using a pipette, and a certain amount of NaOH solution was added to adjust the pH to 11–12. The extract was dispersed in a diatomaceous earth solid-phase supported liquid-liquid extraction column and eluted with 10–50 mL of n-hexane.

[0025] In a specific embodiment, the extract is dispersed in a diatomaceous earth solid-phase supported liquid-liquid extraction column by loading the extract into the column and allowing it to stand for 5-10 minutes.

[0026] In a specific implementation, before HPLC-MS / MS analysis, the eluent obtained by elution with n-hexane is dried using a nitrogen concentrator and then reconstituted with 100~500 µL of 5~10% ammonia-methanol solution.

[0027] In a specific implementation, 50-200 µL of mixed internal standard solution (d7-1-aminonaphthalene, d7-2-aminonaphthalene, d9-3-aminobiphenyl, d9-4-aminobiphenyl) is added before ultrasonic extraction.

[0028] In a specific implementation, the concentration of the NaOH solution is 5~10 mol / L.

[0029] In specific implementations, the ambient air sampling standards refer to standards GB / T 18883-2022 and GB3095-2012.

[0030] The embodiments of the present invention will be further described below with reference to specific examples. Unless otherwise specified, the chemical reagents involved in the following examples are all commercially available conventional products.

[0031] I. Specific Embodiments of the Method for Enriching Aromatic Amine Compounds in Ambient Air of the Present Invention Example 1 The enrichment method for aromatic amine compounds in ambient air in this embodiment is as follows: Environmental smoke samples were collected from a smoking room using a glass fiber filter membrane at a flow rate of 15 L / min for 40 h. After sampling, the glass fiber filter membrane was placed in a collection container, and 25 mL of 5% HCl solution was added, followed by 50 µL of a mixed internal standard solution (d7-1-aminonaphthalene, d7-2-aminonaphthalene, d9-3-aminobiphenyl, d9-4-aminobiphenyl). After ultrasonic extraction for 30 min, 10 mL of the extract was accurately transferred using a pipette, and a certain amount of 5 mol / L NaOH solution was added to adjust the pH of the extract to 10-11, resulting in a mixed solution. This mixed solution was then loaded onto a solid-phase supported liquid-liquid extraction column (ISOLUTE). ® In SLE+, after standing for 10 min, elute with 25 mL of n-hexane to obtain the eluent. Dry the eluent using a nitrogen concentrator, and then redissolve it with 100 µL of 5% ammonia-methanol solution to obtain the test solution.

[0032] Example 2 The enrichment method for aromatic amine compounds in ambient air in this embodiment is as follows: Ambient air samples from a dye chemical plant were collected using a glass fiber filter membrane at a flow rate of 5 L / min for 20 h. After sampling, the glass fiber filter membrane was placed in a collection container, and 25 mL of 5% HCl solution was added, followed by 50 µL of a mixed internal standard solution (d7-1-aminonaphthalene, d7-2-aminonaphthalene, d9-3-aminobiphenyl, d9-4-aminobiphenyl). After ultrasonic extraction for 30 min, 5 mL of the extract was accurately transferred using a pipette, and a certain amount of 10 mol / L NaOH solution was added dropwise to adjust the pH to 10-11, resulting in a mixed solution. This mixed solution was loaded into a diatomaceous earth solid-phase supported liquid-liquid extraction column, allowed to stand for 10 min, and eluted with 50 mL of n-hexane to obtain the eluent. The eluent was dried using a nitrogen concentrator and then reconstituted with 200 µL of 5% ammonia-methanol solution to obtain the test solution.

[0033] II. Specific Embodiments of the Method for Detecting Aromatic Amine Compounds in Ambient Air of the Present Invention Example 3 The method for detecting aromatic amine compounds in ambient air in this embodiment is as follows: The test solutions obtained after enrichment using the methods for enriching aromatic amine compounds in ambient air as described in Examples 1-2 were analyzed by HPLC-MS / MS.

[0034] The chromatographic conditions for HPLC-MS / MS analysis were as follows: Column: Waters Symmetry Shield TM RP18 (150mm × 2.1mm id, 3.5 μm); Column temperature: 30℃ o C; Injection volume: 10 μL; Pre-equilibration time: 10 min; Mobile phase A: 0.1% (v / v) formic acid-water solution, Mobile phase B: 0.1% (v / v) formic acid-acetonitrile solution; Gradient elution conditions: 0~3 min, 100% A; 3.1~17 min, 78% A; 17.1~22 min, 100% B; 22.1~33 min, 100% A. The gradient elution conditions are shown in Table 1.

[0035] Table 1. Gradient elution conditions for chromatography The mass spectrometry conditions for HPLC-MS / MS analysis were as follows: ion source: electrospray ionization (ESI); scan mode: positive ion scan; detection mode: multiple reaction monitoring (MRM); electrospray voltage: 5500 V; curtain gas pressure: 30 psi; auxiliary gas Gas1 pressure: 70 psi; auxiliary gas Gas2 pressure: 70 psi; ion source temperature: 500 °C. oC. The quantitative ion pairs, qualitative ion pairs, residence time, collision energy (CE), and declustering voltage (DP) of each compound are shown in Table 2.

[0036] Table 2. Quantitative ion pairs, qualitative ion pairs, residence time, collision energy (CE), and declustering voltage (DP) for each compound. III. Experimental Examples (1) Tests for recovery rate, limit of detection, and limit of quantitation A mixed standard stock solution containing four aromatic amine compounds (concentrations of 0.5 µg / mL for 1-aminonaphthalene, 2-aminonaphthalene, 3-aminobiphenyl, and 4-aminobiphenyl, respectively) was prepared using 5% ammonia / methanol. A mixed internal standard stock solution was also prepared. Different volumes of the mixed standard stock solution were then added to form a series of mixed standard working solutions. These mixed standard working solutions contained internal standards d7-1-aminonaphthalene, d7-2-aminonaphthalene, d9-3-aminobiphenyl, and d9-4-aminobiphenyl at concentrations of 10 ng / mL, 10 ng / mL, 5 ng / mL, and 5 ng / mL, respectively. The series of mixed standard working solutions were analyzed by HPLC-MS / MS, and linear regression was performed on the peak area ratio of aromatic amine compounds to internal standards against the concentration ratio to obtain standard working curves for each target compound. Among them, d7-1-aminonaphthalene is the internal standard for 1-aminonaphthalene; d7-2-aminonaphthalene is the internal standard for 2-aminonaphthalene; d9-3-aminobiphenyl is the internal standard for 3-aminobiphenyl; and d9-4-aminobiphenyl is the internal standard for 4-aminobiphenyl.

[0037] The recovery rate of the detection method was investigated. Indoor air samples were collected according to Example 1, and the recovery rate was determined at low, medium, and high levels. The lowest concentration of the mixed standard working solution was used for 10 parallel determinations, and the standard deviation was calculated. Three times the standard deviation was defined as the limit of detection, and ten times the standard deviation was defined as the limit of quantitation. The intra-day and inter-day precision of aromatic amine compounds was also investigated. The results are shown in Table 3.

[0038] Table 3. Linear regression equation, recovery rate, limit of detection, limit of quantitation, and precision test results. (2) Actual sample test results The test results of aromatic amine compounds in environmental smoke samples collected from different smoking rooms in Example 1 are shown in Table 4. The MRM diagram of aromatic amine compounds in a typical ambient air sample (Sample 1) from Example 1 is shown below. Figure 1 As shown, where, Figure 1 a is the MRM diagram of 1-aminonaphthalene (1-NA) and 2-aminonaphthalene (2-NA). Figure 1b is the MRM diagram of 3-aminobiphenyl (3-ABP) and 4-aminobiphenyl (4-ABP).

[0039] Table 4. Content of aromatic amine compounds in ambient smoke samples from different smoking rooms (pg / m³) 3 ) The test results of aromatic amine compounds in ambient air samples collected from different sampling points of a dye chemical plant in Example 2 are shown in Table 5.

[0040] Table 5. Content of aromatic amine compounds in ambient air samples from different sampling points of a dye chemical plant (pg / m³) 3 ) Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for enriching aromatic amine compounds in ambient air, characterized in that, Includes the following steps: Ambient air samples were collected using a glass fiber filter membrane, and the extract was obtained by adding acid. The extract was then adjusted to be alkaline and dispersed in a diatomaceous earth solid-phase supported liquid-liquid extraction column, and eluted with n-hexane.

2. The method for enriching aromatic amine compounds in ambient air as described in claim 1, characterized in that, The diatomaceous earth solid-phase supported liquid-liquid extraction column is ISOLUTE. ® SLE+.

3. The method for enriching aromatic amine compounds in ambient air as described in claim 1, characterized in that, Add 10-50 mL of n-hexane for every 5-20 mL of extract.

4. The method for enriching aromatic amine compounds in ambient air as described in claim 1, characterized in that, The extract is adjusted to be alkaline by adding an alkaline solution, namely sodium hydroxide solution, to adjust the pH of the extract to 10-12.

5. The method for enriching aromatic amine compounds in ambient air as described in claim 1, characterized in that, The extraction was performed by ultrasonic extraction, and the ultrasonic extraction time was 10-60 min.

6. The method for enriching aromatic amine compounds in ambient air as described in claim 1, characterized in that, The acid solution is hydrochloric acid, and the mass concentration of hydrochloric acid is 5-10%.

7. The method for enriching aromatic amine compounds in ambient air as described in claim 1, characterized in that, The aromatic amine compounds include 1-aminonaphthalene, 2-aminonaphthalene, 3-aminobiphenyl, and 4-aminobiphenyl.

8. A method for detecting aromatic amine compounds in ambient air, characterized in that, After enrichment using the method described in any one of claims 1-7, aromatic amine compounds in ambient air are analyzed by HPLC-MS / MS.

9. The method for detecting aromatic amine compounds in ambient air as described in claim 8, characterized in that, The chromatographic conditions for HPLC-MS / MS analysis were as follows: Column: Waters Symmetry Shield TM RP18; Column temperature: 30~40 o C; Injection volume: 10~15 μL; Pre-equilibration time: 10~15 min; Mobile phase A: 0.1 vol % formic acid-water solution, Mobile phase B: 0.1 vol % formic acid-acetonitrile solution; Gradient elution conditions: 0~3 min, 100% A; 3.1~17 min, 78% A; 17.1~22min, 100%B; 22.1~33min, 100%A.

10. The method for detecting aromatic amine compounds in ambient air as described in claim 8, characterized in that, The mass spectrometry conditions for HPLC-MS / MS analysis were as follows: ion source: electrospray ionization source; scanning mode: positive ion scan; detection mode: multiple reaction monitoring mode; electrospray voltage: 5500~6000 V; curtain gas pressure: 30~40 psi. Auxiliary gas pressure 1: 70~80 psi; Assist gas pressure: 70~80 psi; Ion source temperature: 500~550℃ o C.

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