A rapid detection method for phenolic compounds in water

Abstract

The present application provides a method for rapid detection of phenolic compounds in water, which relates to the field of water quality detection. The method includes the following steps: S1. Preparation of instruments and reagents, gas chromatography-mass spectrometry, capillary gas chromatography column, filled adsorption microextraction device, semi-automatic device that can automatically adjust the extraction rate and number of cycles, MEPS filler HLB; glass bottles, sample bottles, acetonitrile, and experimental water are ultrapure water; S2. Initial sample collection, using multiple glass bottles, collecting surface water samples from reservoirs A, B, C, and D, and refrigerating them for storage; S3. Second sample collection, after filtering the sample with a filter membrane, taking an appropriate amount of water sample into the sample bottle and adjusting the pH value; S4. Extraction head sampling. Compared with conventional solid-phase extraction methods, this method has the characteristics of simplified sample processing, short time, and easy operation, and this method has a low detection limit and good precision and accuracy.

Description

Technical Field

[0001] The present application relates to the technical field of water quality detection, and in particular to a method for rapid detection of phenolic compounds in water. Background Art

[0002] Phenolic compounds, hydroxyl derivatives of benzene or fused-ring compounds, are among the most common organic pollutants in water. A wide variety of phenolic compounds exist in the environment, depending on their substitutable positions (including phenol, 2,4-dimethylphenol, 2-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol, p-chloro-m-cresol, pentachlorophenol, 2-nitrophenol, 4-nitrophenol, 2,4-dinitrophenol, 4,6-dinitro-o-cresol, and m-cresol). Phenolics play a crucial role in the chemical industry, serving as raw materials, intermediates, and products in industries such as coking, pharmaceuticals, textiles, natural gas, and petrochemicals. During production and use, they can enter the environment through waste gases or wastewater. Phenolics have attracted widespread attention.

[0003] Common methods for detecting phenols include gas chromatography and liquid chromatography. Gas chromatography-hydrogen flame ionization detection (GC-FID) can directly detect phenols, but its sensitivity is relatively low. Alternatively, phenols can be derivatized and detected using an electron capture detector (ECD). Derivatization agents commonly used include bromomethylpentafluorobenzene, pentafluorobenzoyl chloride, and heptafluorobutyric anhydride. These derivatization agents are difficult to synthesize, and the derivatization process is difficult to control and cumbersome to operate. High-performance liquid chromatography (HPLC) does not require derivatization, but as a broad-spectrum detector, its qualitative capabilities are relatively poor. The analysis of phenolic compounds in water requires sample pretreatment to remove interfering compounds and enrich the target compound to improve sensitivity. Currently, common pretreatment methods include liquid-liquid extraction (LIE) and solid-phase extraction (SPE). A related study investigated the LLE process for 14 phenolic compounds in water and ultimately determined that a 4:1 dichloromethane / ethyl acetate mixture was the optimal solvent, achieving recoveries of 82.1-109.3% for the 14 phenolic compounds. While LLE is simple to operate and requires minimal instrumentation, it consumes a significant amount of organic solvent and is complex. Solid-phase extraction (SPE) is currently the most mainstream analytical method. Other related techniques use acetonitrile containing 1% acetic acid to elute HLB solid-phase extraction columns to extract phenolic compounds from water. The recovery rate for 11 phenols in surface water can reach 98.5-116%, with a precision range of 3.58-4.67% and a detection limit of 0.1-0.5 μg / L. In addition to liquid-liquid extraction and solid-phase extraction (SPE), other pretreatment methods for detecting phenolic compounds in water include SPME and DLLME, but these are not widely used. Furthermore, a comparison of liquid-liquid extraction, solid-phase extraction, and solid-phase microextraction (SPE) was conducted. The results showed that liquid-liquid extraction had a lower recovery rate, while SPE and SPE had better recovery rates and stability when testing actual water samples.

[0004] MEPS (Solid Phase Microextraction) is a novel solid-phase microextraction technique proposed by Abdel-Rehim of Sweden in 2004. Its initial development was for the analysis of drugs and their metabolites in small volumes of biological fluids, such as urine and blood. Due to its economical, convenient, rapid, and environmentally friendly characteristics, it has rapidly gained popularity in the pharmaceutical, food, health, and environmental fields. Based on the principles of solid-phase extraction (SPE), MEPS utilizes a packed adsorbent for microextraction. The miniaturization of the packed bed apparatus reduces the volume from milliliters to microliters. Because MEPS shares the same separation chemistry as SPE, adsorbents successfully used in SPE extraction are suitable for MEPS. Compared to liquid-liquid extraction, packed adsorption microextraction offers advantages such as reduced operation time, amenability to full automation, the requirement for small extraction solutions, and significantly improved extraction selectivity. Compared to SPE, sample volumes can be reduced from hundreds of milliliters to a few milliliters, significantly saving time. This method also integrates sampling, extraction, and concentration, offering simplicity, rapidity, low cost, minimal use of organic solvents, and environmental friendliness. It also holds great promise for the analysis of environmental water samples. This method has now been commercialized and is very conducive to its promotion and use.

[0005] The present application aims to establish a method for detecting phenolic compounds in water by MEPS-GC-MS based on MEPS-GC-MS. Summary of the Invention

[0006] In order to overcome the existing deficiencies, the embodiment of the present application provides a method for rapid detection of phenolic compounds in water bodies. The method discusses important parameters affecting the MEPS extraction effect, such as extraction materials, number of extraction cycles and extraction rate, elution solvent and elution volume, and sample pH experimental parameters. This method can achieve low detection limits for 12 phenolic compounds in water bodies, with good precision and accuracy.

[0007] The technical solution adopted by the embodiment of the present application to solve the technical problem is: a rapid detection method for phenolic compounds in water, comprising the following steps:

[0008] S1. Prepare instruments and reagents, including a gas chromatograph-mass spectrometer, a capillary gas chromatography column, a packed adsorption microextraction device, a semi-automatic device that automatically adjusts the extraction rate and cycle number, and MEPS filler (HLB). Use ultrapure water for glass bottles, sample bottles, acetonitrile, and experimental water.

[0009] S2. Initial sample collection: Collect surface water samples from Reservoirs A, B, C, and D using multiple glass bottles and store them in a refrigerator.

[0010] S3. Collect samples again, filter the samples through a membrane filter, take an appropriate amount of water sample into a sample bottle, and adjust the pH value;

[0011] S4. Extraction head sampling is further divided into the following steps:

[0012] (1) The extraction head was rinsed with acetonitrile and pure water in turn, and an appropriate amount of sample was absorbed;

[0013] (2) Rinse with pure water;

[0014] (3) Extract gas to dry the extraction column;

[0015] (4) Elute with acetonitrile, take an appropriate amount of eluent, and enter GC-MS detection.

[0016] Furthermore, the chromatographic conditions of the gas chromatography-mass spectrometry instrument selected in step S1 are:

[0017] Carrier gas flow rate: 1.0 mL / min; chromatographic column temperature: 35°C for 5 min, then increase the temperature to 230°C at 8°C / min, and then increase the temperature to 280°C at 25°C / min; injection port temperature: 280°C; injection port: split / splitless capillary column injection port; injection mode: split injection, split ratio 2:1.

[0018] Furthermore, the mass spectrometry conditions of the gas chromatography-mass spectrometry instrument selected in step S1 are:

[0019] Ion source: EI; interface temperature: 280°C; ion source temperature: 230°C; quadrupole temperature: 150°C; ionization energy: 70 eV; full scan mode: scanning range: 45-450 amu.

[0020] Furthermore, the gas chromatography column selected in step S1 is a DB-5 non-polar chromatography column, the coating of which is 5% phenyl-95% methylsilane.

[0021] Furthermore, in step S1, the weight of the MEPS filler HLB was 4 mg, so that during the experimental process of step S4, the recovery rate of phenol was 94.3%, and the recovery rate of all phenols ranged from 79.5% to 96.9%.

[0022] Furthermore, in step S3, acetic acid is used to adjust the pH value to 2.

[0023] Furthermore, in sub-step (1) of step S4, when sampling the extraction head, the extraction head is rinsed with 150 μL of acetonitrile containing 0.2% formic acid and pure water, and 2 mL of sample is absorbed. The number of extraction cycles is selected to be 30 times, and the absorption and discharge speed is adjusted to 15 μL / s.

[0024] Furthermore, in sub-step (2) of step S4, 500 μL of pure water is used for rinsing.

[0025] Furthermore, in sub-step (3) of step S4, after the sample is loaded into the MEPS, the adsorbent is dried by extracting air or nitrogen, and the extraction times are specifically 500 μL of air 20 times to dry the extraction column.

[0026] Furthermore, in sub-step (4) of step S4, the elution solvent is acetonitrile containing 0.2% formic acid, the elution volume is 100 μL of acetonitrile containing 0.2% formic acid, and after elution, 1.0 μL of the eluate is taken and entered into GC-MS detection.

[0027] The advantages of the embodiments of this application include the development of a detection technology for phenolic compounds in water based on MEPS-GC-MS. Compared with conventional solid-phase extraction methods, this technology simplifies the sample processing process, shortens the time, and is easy to operate. The sample pretreatment process can be completed in just a few minutes. Experimental results show that this method has a low detection limit and good precision and accuracy, providing a new analytical method for the detection of phenolic compounds in water. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A flow chart of a method for rapid detection of phenolic compounds in water provided in an embodiment of the present application;

[0029] Figure 2 Separation diagram of 12 phenols provided in the embodiment of this application on a DB-5 chromatographic column;

[0030] Figure 3 A graph showing the recovery rate of phenols when using different adsorbents provided in an embodiment of the present application;

[0031] Figure 4 A diagram showing the effect of the number of extraction cycles on the extraction effect provided in an embodiment of the present application;

[0032] Figure 5 A diagram showing the effect of extraction speed on extraction effect provided in an embodiment of the present application;

[0033] Figure 6 This is a diagram showing the effect of the number of blow-drying times on the extraction effect provided in an embodiment of the present application;

[0034] Figure 7 A diagram showing the effect of the elution solvent on the extraction effect provided in an embodiment of the present application;

[0035] Figure 8 A diagram showing the effect of the presence of acid in the elution solvent on the extraction effect provided in an embodiment of the present application;

[0036] Figure 9 A diagram showing the effect of the eluent volume on the extraction effect provided in an embodiment of the present application;

[0037] Figure 10 This is a diagram showing the effect of sample pH on extraction performance provided in an embodiment of the present application. DETAILED DESCRIPTION

[0038] In order to more efficiently detect 12 phenolic compounds (including phenol, 2,4-dimethylphenol, 2-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol, p-chloro-m-cresol, pentachlorophenol, 2-nitrophenol, 4-nitrophenol, 2,4-dinitrophenol, 4,6-dinitro-o-cresol, and m-cresol), the following ideas are as follows:

[0039] Example 1:

[0040] See also Figures 1-10 As shown, a method for rapid detection of phenolic compounds in water comprises the following steps:

[0041] Prepare instruments and reagents, including a gas chromatograph-mass spectrometer, a capillary gas chromatography column, a packed adsorption microextraction device, a semiautomatic device that can automatically adjust the extraction rate and number of cycles, and MEPS filler HLB; glass bottles, sample bottles (size 1.5 / 10 mL), acetonitrile, and ultrapure water for the experiments.

[0042] The chromatographic conditions of the gas chromatography-mass spectrometry instrument selected in step S1 are:

[0043] Carrier gas flow rate: 1.0 mL / min; chromatographic column temperature: 35°C (5 min), 8°C / min to 230°C (0 min), 25°C / min to 280°C (1 min); injection port temperature: 280°C; injection port: split / splitless capillary column injection port; injection mode: split injection, split ratio 2:1.

[0044] The mass spectrometry conditions of the gas chromatography-mass spectrometry instrument selected in step S1 are:

[0045] Ion source: EI; interface temperature: 280°C; ion source temperature: 230°C; quadrupole temperature: 150°C; ionization energy: 70 eV; full scan mode (SCAN): scanning range: 45-450 amu.

[0046] The gas chromatography column selected in step S1 is a DB-5 non-polar chromatography column, which is coated with 5% phenyl-95% methylsilane. Figure 2As shown in the figure, a variety of non-polar and medium-polarity chromatographic columns, DB-5, DB-17, and DB1701, were experimentally compared. Both DB-5 and DB-17 can achieve the separation of 12 phenolic substances. Among them, DB-5, as a low-bleed non-polar chromatographic column (coated with 5% phenyl-95% methylsilane), has obvious advantages in sensitivity and resolution. DB-17 requires high temperature to ensure the separation and determination of components, but high column temperature increases column bleed and the baseline is too high, which affects the determination sensitivity. The figure below shows the separation of 12 phenols on the DB-5 column. Figure 2 , among which, among which, Figure 2 The serial numbers represent: 1. Phenol; 2. 4-nitrophenol; 3. 2,4-dinitrophenol; 4. m-cresol; 5. 2-chlorophenol; 6. 2-nitrophenol; 7. 2,4-dimethylphenol; 8. 4,6-dinitro-o-cresol; 9. p-chlorom-cresol; 10. 2,4-dichlorophenol; 11. 2,4,6-trichlorophenol; 12. Pentachlorophenol.

[0047] In step S1, the weight of the MEPS filler HLB was 4 mg, resulting in a phenol recovery rate of 94.3% during the experimental process of step S4, and the recovery rate of all phenols ranged from 79.5% to 96.9%. It should be noted that the purification and extraction efficiency depends on the selection of extraction materials. Existing extraction materials generally include C18, SIL (silica gel), SAX, and HLB (divinylbenzene-N-vinylpyrrolidone). This application selected C18, SIL (silica gel), SAX, and HLB (divinylbenzene-N-vinylpyrrolidone) for comparison (e.g. Figure 3 As shown, C18 is primarily used for hydrophobic compounds and polymers, SIL is suitable for hydrophilic compounds, SAX is suitable for anionic compounds, and HLB is a mixed polymer material suitable for the analysis of a wide range of substances. In this experiment, C18 had low recovery rates for highly polar phenolic compounds, particularly phenol, with a recovery rate of only 37.5%. However, for less polar phenolic compounds, the recovery rate ranged from 74.4% to 94.5%. Because phenols are difficult to hydrolyze into ions in water, SAX also exhibits poor retention for phenols, with recoveries for most phenols below 20%. Silica gel also exhibits weak adsorption for phenolic compounds, with recoveries for most phenols below 40%. HLB, due to its excellent adsorption and separation efficiency, achieves high recovery rates in practical applications, with a phenol recovery rate of 94.3% and recoveries for all phenols ranging from 79.5% to 96.9%. HLB was ultimately selected as the extraction material.

[0048] S2. For the initial sample collection, use multiple glass bottles to collect surface water samples from Reservoirs A, B, C, and D, and store them in a refrigerator.

[0049] In step S2, the glass bottle is a 100 mL brown glass bottle, which is refrigerated and stored at 4°C after collection and analyzed within 2 days.

[0050] S3. Collect samples again, filter the samples with a membrane, take an appropriate amount of water sample into a sample bottle, and adjust the pH value.

[0051] In step S3, acetic acid is used to adjust the pH value to 2.

[0052] Specifically, the pH value of the water sample was adjusted with acetic acid in the range of 1-7. The results showed that (e.g. Figure 10 As shown in Figure 2, pH 2 is the most suitable pH value for the sample.

[0053] S4. Extraction head sampling is further divided into the following steps:

[0054] (1) The extraction head was rinsed with acetonitrile and pure water in turn, and an appropriate amount of sample was absorbed;

[0055] In sub-step (1) of step S4, when sampling the extraction head, the extraction head is rinsed with 150 μL of acetonitrile containing 0.2% formic acid and pure water, and 2 mL of sample is absorbed. The number of extraction cycles is selected as 30 times, and the absorption and discharge speed is adjusted to 15 μL / s.

[0056] Regarding the above-mentioned number of extraction cycles and extraction speed, it should be noted that, generally, SPE solvent elution only has the process from top to bottom, but MEPS is a needle-tube design, and the solvent outlet only has one needle. Therefore, the solvent needs to go through two processes, from bottom to top and from top to bottom, to flow out. The two processes together are called a cycle. Since the sample volume of SPE can sometimes reach hundreds of milliliters or even liters, a sample loading process sometimes takes several hours, and due to the influence of column loading capacity, it is impossible to load too many samples. However, due to the small sample volume of MEPS, the sample can be repeatedly circulated and extracted in the needle tube, thereby improving the extraction efficiency. If the number of extraction cycles is small and the sample is not balanced between the stationary phase and the organic phase, the recovery rate of the target substance will be low; if the number of extractions is too many, the adsorption capacity of the adsorbent is saturated and it is back-extracted into the mobile phase, and the recovery rate will also be slightly reduced. The single-cycle extraction concentration obtained by dividing the total recovery concentration by the number of cycles is converted into the recovery rate and plotted against the number of cycles to obtain the effect of the number of cycles. Figure 4It can be seen that the number of cycles basically reaches a balance after 25 times. Taking into account the experimental speed and ensuring sufficient signal responsiveness, 30 cycles are selected for the experiment. The extraction speed directly affects the extraction efficiency. When the extraction speed is too fast, the target and the stationary phase are not in sufficient contact, resulting in a low recovery rate. In addition, too fast an extraction speed will also lead to the entry of bubbles and increased pressure, making it difficult to accurately quantify. It is also easy to cause blockage, which brings difficulties to actual operation. In actual experiments, it was found that the recovery rate of most phenolic compounds was best at a flow rate of 15μL / s (such as Figure 5 shown).

[0057] (2) Rinse with pure water;

[0058] In sub-step (2) of step S4, 500 μL of pure water is used for rinsing.

[0059] (3) Extract gas to dry the extraction column;

[0060] In sub-step (3) of step S4, after the sample is loaded into the MEPS, the adsorbent is dried by extracting air or nitrogen, and the extraction times are specifically 500 μL of air 20 times to dry the extraction column.

[0061] Specifically, because gas chromatography columns are typically capillary columns, the stationary phase has a low surface energy. Water, with its high surface energy and boiling point, has poor wetting properties. If the GC loading solvent contains water, it forms a smooth solvent film on the column walls, while some water flows through the column as a liquid. The presence of these droplets can cause band broadening or even peak splitting of solutes in the water. Furthermore, non-volatile substances, such as salts, carried by the water during column loading can contaminate the column. For mass spectrometer detectors, the presence of water can significantly reduce the life of the filament that provides energy for EI. Therefore, GC loading generally avoids the use of aqueous solvents, and water removal is performed during pretreatment. After loading in MEPS, some water remains attached to the adsorbent, which is typically dried by evacuating air or nitrogen. While silica-based stationary phases, such as silica gel, are generally not suitable for drying, polymer-based phases, such as HLB, do not affect the solid-phase extraction process. In this experiment, air was extracted as a means of drying the adsorbent. The effect of the number of extractions on the recovery rate of the target substance is as follows: Figure 6 As shown in the figure, the results show that in actual experiments, the number of extractions has little effect on the recovery rate. Generally, after 15 times, the recovery rate is close to the stable range. However, considering the differences in samples, 500 μL of air is extracted 20 times to dry the extraction column.

[0062] (4) Elute with acetonitrile, take an appropriate amount of eluent, and enter GC-MS detection.

[0063] In sub-step (4) of step S4, the elution solvent is acetonitrile containing 0.2% formic acid, the elution volume is 100 μL of acetonitrile containing 0.2% formic acid, and 1.0 μL of the eluate is taken after elution and entered into GC-MS detection.

[0064] Regarding the elution solvent and elution volume, it should be noted that due to the large differences in polarity of the twelve phenolic compounds, an elution solvent with stronger polarity is required. In the related technologies of SPE analysis of phenols, ethyl acetate and dichloromethane are generally more effective in C18 and PSD columns; in HLB columns, acid-containing acetonitrile is more effective. First, six solvents including methanol (MeOH), acetonitrile (ACN), acetone (ATN), ethyl acetate (EtOAc), dichloromethane (DCM), and methyl tert-butyl ether (MTBE) were compared. The polarity order of these six solvents is: MTBE<DCM<EtOAc<ATN<MeOH<ACN, and the recovery performance is basically close to this ( Figure 7 ), MTBE and DCM have poor elution ability and can hardly elute phenols with strong polarity; EtOAc and ATN have elution efficiency of 20%-70% for most phenols; MEOH and ACN have a recovery rate of more than 85% for phenol with strong polarity.

[0065] Since phenols have strong polarity, adding a certain amount of acid to the solvent can effectively improve the recovery rate. The experiment was conducted on six solvents: methanol, acetonitrile, acetonitrile (containing 0.1% acetic acid), acetonitrile (containing 0.1% MF), acetonitrile (containing 0.2% MF), and acetonitrile (containing 0.3% MF). Figure 8 It was found that the addition of acetonitrile containing 0.2% formic acid had the best elution effect for most phenols.

[0066] In the elution volume experiment, 100µL 0.2% formic acid in acetonitrile is the optimal elution volume, which can meet the elution requirements of most phenols (such as Figure 9 shown).

[0067] Furthermore, the 12 phenolic compounds exhibited good linearity in the gas chromatographic response over a concentration range of 0.05 to 10 mg / L, with correlation coefficients (R²) ranging from 0.9931 to 0.9997, meeting the requirements for quantitative analysis. At a signal-to-noise ratio of 3 (S / N=3), the method detection limits for the 12 phenolic compounds in water reached 0.1 to 1.9 μg / L (Table 1), meeting the national surface water standard limits. Precision measurements were performed on spiked water samples containing phenolic compounds at concentrations ranging from 5.0 to 25.0 μg / L, with relative standard deviations (RSDs) ranging from 3.4% to 19.3% across six replicates. Following the analytical conditions and procedures specified in this method, water samples were spiked three times at different concentrations of phenolic compounds (50.0-250.0, 12.5-62.5, and 5.0-25.0 μg / L). Spiked recoveries ranged from 79.1% to 111%, with relatively poor recoveries at low concentrations. Specific precision and accuracy data are shown in Table 2.

[0068] Table 1 Detection limits of phenolic compounds Unit: μg / L

[0069]

[0070] Table 2 Method precision and accuracy

[0071]

[0072] In summary, this application establishes a method for detecting phenolic compounds in water based on packed adsorption microextraction-gas chromatography-mass spectrometry. Important parameters affecting the effectiveness of the method, such as the extraction material for packed adsorption microextraction, the number of extraction cycles and extraction speed, the elution solvent and elution volume, and the sample pH, were tested and optimized. The optimal conditions were determined to be: first, the sample pH was adjusted to 2, HLB was used as the extraction material, and the extraction was repeated 30 times at a speed of 15µL / s, followed by a rinse with 500µL of pure water. Afterwards, 500µL of air was drawn 20 times to dry the extraction column, and then eluted with 100µL of acetonitrile containing 0.2% formic acid. The 12 target compounds were well separated within 30 minutes and had good linearity in the range of 0.05-10mg / L, with correlation coefficients ranging from 0.9931 to 0.9997 and a detection limit of 0.1-1.9µg / L. In the three-level spiked experiments, the average recoveries of phenols ranged from 79.1% to 111%, with relative standard deviations ranging from 3.4% to 19.3%. This method can meet the requirements for the rapid determination of phenols in water.

[0073] Finally, it should be noted that the above embodiments are merely examples for the purpose of illustrating the present invention and are not intended to limit the embodiments. Those skilled in the art will readily appreciate that other variations or modifications based on the above description are possible. It is not necessary and impossible to provide an exhaustive list of all embodiments. However, obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A rapid detection method for phenolic compounds in water, characterized in that: The phenolic compounds include phenol, 2,4-dimethylphenol, 2-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol, p-chloro-m-cresol, pentachlorophenol, 2-nitrophenol, 4-nitrophenol, 2,4-dinitrophenol, 4,6-dinitro-o-cresol and m-cresol, and specifically include the following steps: S1. Prepare instruments and reagents, including a gas chromatograph-mass spectrometer, a capillary gas chromatography column, a packed adsorption microextraction device, a semi-automatic device that automatically adjusts the extraction rate and cycle number, and MEPS filler (HLB). Use ultrapure water for glass bottles, sample bottles, acetonitrile, and experimental water. S2. Initial sample collection: Collect surface water samples from Reservoirs A, B, C, and D using multiple glass bottles and store them in a refrigerator. S3. Collect samples again, filter the samples through a membrane filter, take an appropriate amount of water sample into a sample bottle, and adjust the pH value; S4. Extraction head sampling is further divided into the following steps: (1) The extraction head was rinsed with acetonitrile and pure water in turn, and an appropriate amount of sample was absorbed; (2) Rinse with pure water; (3) Extract gas to dry the extraction column; (4) Elute with acetonitrile, take an appropriate amount of eluent, and enter GC-MS detection; In sub-step (1) of step S4, when sampling the extraction head, the extraction head is rinsed with 150 μL of acetonitrile containing 0.2% formic acid and pure water, and 2 mL of sample is absorbed. The number of extraction cycles is selected to be 30 times, and the absorption and discharge speed is adjusted to 15 μL / s; In sub-step (2) of step S4, 500 μL of pure water is used for rinsing; In sub-step (3) of step S4, after the sample is loaded into the MEPS, the adsorbent is dried by extracting air or nitrogen, and the extraction times are specifically 500 μL of air 20 times to dry the extraction column; In sub-step (4) of step S4, the elution solvent is acetonitrile containing 0.2% formic acid, the elution volume is 100 μL of acetonitrile containing 0.2% formic acid, and 1.0 μL of the eluate is taken after elution and entered into GC-MS detection.

2. The method for rapid detection of phenolic compounds in water according to claim 1, wherein The chromatographic conditions of the gas chromatography-mass spectrometry instrument selected in step S1 are: Carrier gas flow rate: 1.0 mL / min; chromatographic column temperature: 35°C for 5 min, then increase the temperature to 230°C at 8°C / min, and then increase the temperature to 280°C at 25°C / min; injection port temperature: 280°C; injection port: split / splitless capillary column injection port; injection mode: split injection, split ratio 2:

1.

3. The rapid detection method for phenolic compounds in water according to claim 1, wherein The mass spectrometry conditions of the gas chromatography-mass spectrometry instrument selected in step S1 are: Ion source: EI; interface temperature: 280°C; ion source temperature: 230°C; quadrupole temperature: 150°C; ionization energy: 70 eV; full scan mode: scanning range: 45-450 amu.

4. The rapid detection method for phenolic compounds in water as claimed in claim 1, wherein The gas chromatography column selected in step S1 is a DB-5 non-polar chromatography column, the coating of which is 5% phenyl-95% methylsilane.

5. The rapid detection method for phenolic compounds in water as claimed in claim 1, wherein In step S1 , the weight of the MEPS filler HLB is 4 mg.

6. The method for rapid detection of phenolic compounds in water according to claim 1, wherein In step S3, acetic acid is used to adjust the pH value to 2.

Images