High-throughput detection method for liquid crystal monomer in sediment

Abstract

The invention discloses a high-throughput detection method for liquid crystal monomers in sediments, which comprises the following steps: extracting, enriching, purifying and removing impurities from the sediments, measuring by using a gas chromatograph-quadrupole rod-electrostatic field ion orbitrap combined high-resolution mass spectrometer, and analyzing to obtain the types and contents of the liquid crystal monomers in the sediments. According to the method, various liquid crystal monomers can be simultaneously and rapidly determined, impurity interference in a sample is effectively removed by utilizing extraction, enrichment and purification impurity removal, the chromatographic separation efficiency is improved, the anti-interference capability is improved by utilizing the extremely high resolution of the electrostatic field ion orbitrap high-resolution mass spectrum, the background interference is effectively reduced, and the detection accuracy is improved. Meanwhile, ultrasonic-assisted extraction and solid-phase extraction technologies are combined to purify a target object, so that the tedious steps of sample pretreatment are simplified, and the detection limit of the detection method is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical detection, and specifically relates to a high-throughput detection method for liquid crystal monomers in sediments. Background Art

[0002] Liquid Crystal Monomers (LCMs) are a new type of pollutant with persistence, bioaccumulation and toxicity (P&B&T) that widely exist in liquid crystal displays. Due to the limited life cycle and fast update speed of electronic products, a large number of old liquid crystal displays are eventually phased out and enter their scrapping stage, where they are disassembled, recycled and finally disposed of at e-waste recycling sites. In addition, LCMs do not have chemical bonding on liquid crystal displays and are prone to release into the surrounding environment during production, use, recycling and disposal.

[0003] Liquid crystal monomers can enter the water environment through various channels such as atmospheric dry and wet deposition, effluent from sewage treatment plants, and surface runoff, and participate in environmental migration and bioaccumulation processes. Indoor dust, as an important initial release source of LCMs, mainly comes from the aging and wear of electronic display devices (such as computers, mobile phones, etc.), and enters the air environment through electrostatic adsorption or particulate matter carrying. During the exchange process between indoor and outdoor media, these LCM-containing particulate matters can migrate to the marine environment through atmospheric dry and wet deposition, constituting a key pathway for the long-distance transport of LCMs. At the same time, the effluent from sewage treatment plants is an important pathway for LCMs to enter the water environment. Since the existing treatment processes cannot completely remove such substances, some residual LCMs are discharged into the receiving water body with the effluent. In addition, the concentration of ∑LCMs in landfill leachate can reach 410 - 1100 ng / L, and it may directly enter the coastal waters through surface runoff or pipeline leakage. The LCMs entering the water environment show obvious environmental fate characteristics, mainly enriched in sediments and aquatic organisms.

[0004] Marine sediments play a key role in the environmental fate of pollutants and are considered important sinks for pollutants. Since sediments can adsorb and accumulate pollutants for a long time, they have become an important medium for assessing environmental pollution status. Emerging pollutants (such as PFAS, OPEs, antibiotics, etc.) are ubiquitous in marine sediments and may have long-term effects on the ecosystem. However, the current research on LCMs in marine sediments still needs to be supplemented. The octanol-water partition coefficients of LCMs are usually high (logKow>5), so they have high hydrophobicity, which makes the occurrence of LCMs in sediments more abundant. In addition, LCMs have different groups and central bridging bonds, and their physicochemical properties vary greatly, which also poses a great challenge to the detection and analysis of LCMs. To comprehensively investigate the ecological occurrence of LCMs, how to develop a detection method that can cover as many liquid crystal monomers as possible has become a difficult problem that researchers urgently need to solve.

[0005] Chinese patent documents with publication numbers CN115684426A and CN112964799A respectively disclose a method for simultaneously analyzing different types of liquid crystal monomers based on GC-APCI-MS / MS technology and a method for quantitatively analyzing fluorinated benzene-based and cyclohexane-based liquid crystal monomers based on GC-MS / MS technology, but both focus on the detection of 20-40 targeted LCMs. Structurally, liquid crystal monomers are a class of synthetic organic compounds with backbone structures such as cyclohexylbenzene, dicyclohexylbenzene, and biphenyl. To meet the performance requirements of different liquid crystal displays, different central bridging bonds (such as: -C≡C-, -N=CH-, -COO-, and -CF2-, etc.) and different functional groups / atoms (fluorine, chlorine, bromine, etc.) are introduced into the backbone structure of liquid crystal compounds. Therefore, the structures of liquid crystal monomers are diverse and complex. Investigations targeting only a small number of monomers cannot comprehensively understand the occurrence of LCMs in the environment. Therefore, it is necessary to develop a high-throughput screening method to identify more LCMs and provide a scientific basis for their environmental behavior, migration mechanism, and ecological risk. Summary of the Invention

[0006] To solve the above technical problems, the present invention provides a high-throughput detection method for liquid crystal monomers in sediments. This detection method can simultaneously determine a total of 88 liquid crystal monomers, and the selectivity and sensitivity of the detection method are high, enabling the rapid identification and trace determination of liquid crystal monomers in sediments.

[0007] A high-throughput detection method for liquid crystal monomers in sediments includes the following steps:

[0008] (1) Extract the liquid crystal monomers in the sediment by ultrasonic-assisted extraction, and obtain an extract after enrichment;

[0009] (2) Purify and remove impurities from the liquid crystal monomers in the extract using a solid-phase extraction cartridge to obtain an eluate;

[0010] (3) The eluate obtained in step (2) is measured by a gas chromatography - quadrupole - electrostatic field ion orbitrap combined high - resolution mass spectrometer, and according to the pre - established standard curve of liquid crystal monomers, the types and contents of liquid crystal monomers in the sediment are analyzed.

[0011] In the present invention, a method for simultaneously and rapidly determining multiple LCMs by ultrasonic - assisted extraction, solid - phase extraction column purification combined with a gas chromatography - quadrupole - electrostatic field ion orbitrap combined high - resolution mass spectrometer is adopted. The pretreatment (extraction, enrichment, and purification to remove impurities) effectively removes the interference of impurities in the sample, improves the chromatographic separation efficiency, and uses the extremely high resolution of the electrostatic field ion orbitrap high - resolution mass spectrometer to improve the anti - interference ability, effectively reducing the background interference. At the same time, ultrasonic - assisted extraction and solid - phase extraction techniques are combined to purify the target substances, simplifying the cumbersome steps of sample pretreatment and reducing the detection limit of the detection method.

[0012] Preferably, in step (1), the sediment is marine sediment, river sediment or lake sediment.

[0013] In the present invention, marine, river or lake sediment can be selected as the test sample, and the above - mentioned detection method can be used to identify liquid crystal monomers in various sediments, providing scientific evidence for the environmental exposure level and ecological toxicity assessment of liquid crystal monomers.

[0014] Preferably, in step (1), the extractants used in the ultrasonic - assisted extraction process are n - hexane and dichloromethane, and the extraction sequence is one extraction with dichloromethane and two extractions with a mixed solution of dichloromethane / n - hexane. The volume of the extractant used each time is the same.

[0015] Further preferably, in the mixed solution of dichloromethane / n - hexane, the volume ratio of dichloromethane to n - hexane is 1:1.

[0016] Preferably, in step (1), the time of ultrasonic - assisted extraction is 15 - 20 min.

[0017] Preferably, step (1) is specifically: the sediment is extracted once with dichloromethane and twice with a mixed solution of dichloromethane / n - hexane, the volume of the extractant used each time is the same, centrifuged after each extraction, and the supernatant is mixed and concentrated by nitrogen blowing to obtain the extract. Preferably, in step (2), the solid - phase extraction column is a florisil solid - phase extraction column, and the loading flow rate of the solid - phase extraction column is maintained at 3 - 4.5 mL / min.

[0018] In the present invention, the solid-phase extraction cartridge can be a solid-phase extraction column for extracting polar substances from non-polar solvents. The Florisil solid-phase extraction column of Waters can be selected. The Florisil solid-phase extraction column can extract polar compounds in the extract, or remove impurities in the extract that cause interference in separation and analysis, which can improve the recovery rate of the analyte, more effectively separate the analyte from the interfering components, reduce matrix interference, and lower the method detection limit.

[0019] Preferably, in step (2), the eluent used in the purification and impurity removal process is n-hexane and dichloromethane.

[0020] Preferably, in step (3), the gas chromatography-quadrupole-electrostatic field ion orbitrap combined high-resolution mass spectrometer uses a DB-5HT weakly polar chromatographic column for chromatographic separation. The specification of the DB-5HT weakly polar chromatographic column is 30m×0.25mm×0.25μm.

[0021] In the present invention, a weakly polar chromatographic column (30m×0.25mm×0.25μm; Agilent) can be used for the separation of weakly polar or medium polar substances, is suitable for the separation of liquid crystal monomers, and has less column bleeding.

[0022] Preferably, in step (3), the gas chromatography conditions of the gas chromatography-quadrupole-electrostatic field ion orbitrap combined high-resolution mass spectrometer are separated using a helium gas flow rate of 1.2 mL / min. The temperature programming is that the initial temperature is 40°C, held for 1 min, then increased to 240°C at a rate of 20°C / min, and subsequently increased to 300°C at a rate of 3°C / min and held for 5 min.

[0023] Preferably, in step (3), the mass spectrometry conditions of the gas chromatography-quadrupole-electrostatic field ion orbitrap combined high-resolution mass spectrometer are as follows: an electron impact ionization source (EI source) is used, the ionization mode is the positive ion mode, the scanning mode is the full scan mode, and the inlet temperature, transfer line temperature, and ion source temperature are 300°C.

[0024] Preferably, the method for establishing the standard curve of the liquid crystal monomer is as follows: the liquid crystal monomer standard is respectively prepared into standard working solutions of 0.1~100 ng / L, and detected using a gas chromatography-quadrupole-electrostatic field ion orbitrap combined high-resolution mass spectrometer. The quantitative ion chromatographic peak area of the liquid crystal monomer is used as the ordinate, and the corresponding liquid crystal monomer concentration is used as the abscissa to draw the standard curve.

[0025] Further preferably, the correlation coefficient (R 2 ) of the standard curve of the liquid crystal monomer is 0.9951~0.9999.

[0026] Preferably, the quantitative limit of the detection method is 0.003 - 0.30 ng / g, and the recovery rate of the detection method is 78% - 106%.

[0027] Preferably, step (3) is specifically as follows: The eluate obtained in step (2) is measured by a gas chromatography - quadrupole - electrostatic field ion orbitrap combined high - resolution mass spectrometer, and the conditions are as follows:

[0028] The gas chromatography separation conditions are: The chromatographic column is a DB - 5HTT weakly polar chromatographic column with a specification of 30 m × 0.25 mm × 0.25 μm. The helium gas flow rate for separation is 1.2 mL / min. The temperature programming is that the initial temperature is 40°C, held for 1 min, then heated to 240°C at a rate of 20°C / min, and then heated to 300°C at a rate of 3°C / min and held for 5 min;

[0029] The high - resolution mass spectrometry conditions are: Ion source: Electron impact ionization source; The carrier gas is selected as high - purity helium gas (>99.99%); Data acquisition mode: Full Scan; The inlet temperature is 300°C; Ionization mode: Positive ion mode; The ion source temperature and the transfer line temperature are both 300°C, and the ion source filament voltage is 70 eV; Scanning range m / z = 50 - 600; Trap offset is set to 2; The resolution is 60000;

[0030] And according to the standard curve of the liquid crystal monomer established in advance, the types and contents of the liquid crystal monomers in the sediment are analyzed.

[0031] Preferably, the liquid crystal monomers include 3VbcH, MeO3bcH, 2ObcH3, MeO3cHP, VcHCP, 2O3cHP, 2OdFP3cH, 2CB, 5VbcH, PecHCP, 5MeB, 3cHMeO-MeOdFP, 2OCB, 4cHCP, 3cH4OdFP, MeP2OPa, 2O5cHP, 4CB, 5cH2OdFP, 3cHCaAMeOP, 2BzoFCP, 2PMeOPa, 3OCB, 2bcHtFMeOP, 2bcHtFP, i5CB, 3cHCaA2OP, 2bcHdFP, 3BzoFCP, 3PMeOPa, tFPO-CF2-dF2B, 2cHdFB, 4OCB, tFMeO-3bcHP, 3bcHtFP, 3cHFtFB, MePVbcH, 3bcHdFP, 3cHtFB, 6CB, tFPO-CF2-dF3B, 3cHdFB, 3teFT, 5OCB, 4BzoCP, 7cHCP, 3tFT, BebcHdFP, 4bcHdFP, 7CB, 5BzodFCP, 5PMeOPa, 4cHtFPcHEt, 6OCB, 3Bzo5P, 5bcHtFP, BeOBzoCB, MePBebcH, 5bcHdFP, 5cHtFB, 5cHdFB, 7OCB, 3cH2B, 2OdFP3bcH, 9CB, 2F3T, 8OCB, 3cH3B, CBzo7P, 5Bzo5P, 5Bzo4OP, 9OCB, 5cH2B, 3CT, 5bcH2OdFP, 11CB, 10OCB, 12CB, 2bcHtFB, 3cHBzoCP, 4Bzo8OP, 5CT, 3bcHtFB, 4cHBzoFCP, 12OCB, 3bcHdFB, 5Bzo8OP, and 3cHP3OPa.

[0032] In the present invention, the above-mentioned liquid crystal monomers are specifically as shown in the following table.

[0033] Table 1: Abbreviation and compound information table of 88 liquid crystal monomers

[0034]

[0035]

[0036]

[0037]

[0038] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0039] By establishing and optimizing the pretreatment method, gas chromatography conditions, and tandem mass spectrometry conditions, the present invention can simultaneously determine 88 liquid crystal monomers. This detection method has high selectivity and sensitivity, enabling the rapid identification and trace determination of liquid crystal monomers in sediments. Description of the Drawings

[0040] Figure 1 It is the chromatogram corresponding to 88 liquid crystal monomers in the sediment sample of Example 1. Among them, 1 to 88 are 3VbcH, MeO3bcH, 2ObcH3, MeO3cHP, VcHCP, 2O3cHP, 2OdFP3cH, 2CB, 5VbcH, PecHCP, 5MeB, 3cHMeO-MeOdFP, 2OCB, 4cHCP, 3cH4OdFP, MeP2OPa, 2O5cHP, 4CB, 5cH2OdFP, 3cHCaAMeOP, 2BzoFCP, 2PMeOPa, 3OCB, 2bcHtFMeOP, 2bcHtFP, i5CB, 3cHCaA2OP, 2bcHdFP, 3BzoFCP, 3PMeOPa, tFPO-CF2-dF2B, 2cHdFB, 4OCB, tFMeO-3bcHP, 3bcHtFP, 3cHFtFB, MePVbcH, 3bcHdFP, 3cHtFB, 6CB, tFPO-CF2-dF3B, 3cHdFB, 3teFT, 5OCB, 4BzoCP, 7cHCP, 3tFT, BebcHdFP, 4bcHdFP, 7CB, 5BzodFCP, 5PMeOPa, 4cHtFPcHEt, 6OCB, 3Bzo5P, 5bcHtFP, BeOBzoCB, MePBebcH, 5bcHdFP, 5cHtFB, 5cHdFB, 7OCB, 3cH2B, 2OdFP3bcH, 9CB, 2F3T, 8OCB, 3cH3B, CBzo7P, 5Bzo5P, 5Bzo4OP, 9OCB, 5cH2B, 3CT, 5bcH2OdFP, 11CB, 10OCB, 12CB, 2bcHtFB, 3cHBzoCP, 4Bzo8OP, 5CT, 3bcHtFB, 4cHBzoFCP, 12OCB, 3bcHdFB, 5Bzo8OP, 3cHP3OPa. Detailed Embodiments

[0041] The following further describes the present invention in detail with reference to embodiments, but the embodiments of the present invention are not limited to the following examples.

[0042] All raw materials used in the present invention are commercially available.

[0043] Establishment of Standard Curve

[0044] (1) Prepare a mixed standard stock solution with a concentration of 1 mg / L for each of the 88 LCM standards (3VbcH, MeO3bcH, 2ObcH3, MeO3cHP, VcHCP, 2O3cHP, 2OdFP3cH, 2CB, 5VbcH, PecHCP, 5MeB, 3cHMeO-MeOdFP, 2OCB, 4cHCP, 3cH4OdFP, MeP2OPa, 2O5cHP, 4CB, 5cH2OdFP, 3cHCaAMeOP, 2BzoFCP, 2PMeOPa, 3OCB, 2bcHtFMeOP, 2bcHtFP, i5CB, 3cHCaA2OP, 2bcHdFP, 3BzoFCP, 3PMeOPa, tFPO-CF2-dF2B, 2cHdFB, 4OCB, tFMeO-3bcHP, 3bcHtFP, 3cHFtFB, MePVbcH, 3bcHdFP, 3cHtFB, 6CB, tFPO-CF2-dF3B, 3cHdFB, 3teFT, 5OCB, 4BzoCP, 7cHCP, 3tFT, BebcHdFP, 4bcHdFP, 7CB, 5BzodFCP, 5PMeOPa, 4cHtFPcHEt, 6OCB, 3Bzo5P, 5bcHtFP, BeOBzoCB, MePBebcH, 5bcHdFP, 5cHtFB, 5cHdFB, 7OCB, 3cH2B, 2OdFP3bcH, 9CB, 2F3T, 8OCB, 3cH3B, CBzo7P, 5Bzo5P, 5Bzo4OP, 9OCB, 5cH2B, 3CT, 5bcH2OdFP, 11CB, 10OCB, 12CB, 2bcHtFB, 3cHBzoCP, 4Bzo8OP, 5CT, 3bcHtFB, 4cHBzoFCP, 12OCB, 3bcHdFB, 5Bzo8OP, 3cHP3OPa) in n-hexane, and use this stock solution to prepare mixed standard working solutions with concentrations ranging from 0.1 to 100 ng / L.

[0045] (2) Preparation of the standard curve: Use a gas chromatography - quadrupole - electrostatic field ion orbitrap combined high-resolution mass spectrometer for determination. The test conditions are as follows:

[0046] Gas chromatograph: GC 1610 from Thermo

[0047] The gas chromatography separation conditions were as follows: The chromatographic column was an Agilent DB-5HT column (30 m × 0.25 mm × 0.25 μm). Separation was carried out using a helium gas flow rate of 1.2 mL / min. The temperature programming was as follows: The initial temperature was 40 °C, held for 1 min, then increased to 240 °C at a rate of 20 °C / min, and subsequently increased to 300 °C at a rate of 3 °C / min and held for 5 min;

[0048] The high-resolution mass spectrometry conditions were as follows: Thermo's Obitrap Exploris high-resolution mass spectrometer; Ion source: EI; Carrier gas selected high-purity helium gas (>99.99%); Data acquisition mode: Full Scan; Injection port temperature was 300 °C;

[0049] Ionization mode: Positive ion mode; Both the ion source temperature and the transfer line temperature were 300 °C, and the ion source filament voltage was 70 eV; Scanning range m / z = 50 - 600; Trap offset was set to 2; Resolution was 60,000;

[0050] A standard curve was plotted with the chromatographic peak area of the quantitative ion of the standard as the ordinate and the corresponding target substance concentration as the abscissa.

[0051] The results showed that: The correlation coefficients (R 2 ) of the standard curves of 88 LCMs were between 0.9951 and 0.9992, and the method detection limits ranged from 0.003 to 0.30 ng / g.

[0052] Example 1

[0053] Twelve 5 g dry weight marine sediments were taken, and 0 ng, 2 ng, 10 ng, and 50 ng of the mixed standard were added to every three of them respectively.

[0054] (1) Extract once with 15 mL of DCM and extract twice with 15 mL of DCM / HEX (1:1, v / v) (each ultrasonic-assisted extraction step for 15 min). After each extraction, centrifuge at 2000 rpm for 10 min. Mix the supernatant, and then concentrate it under a gentle high-purity nitrogen gas flow close to dryness and redissolve it in 2 mL of DCM to obtain the extract;

[0055] (2) The sample was purified using a Florisil solid-phase extraction column (SPE) (Merck, 1 g, 6 mL). The solid-phase extraction column was pretreated with 6 mL of DCM / HEX (1:1, v / v) and DCM. The extract (2 mL) obtained in step (1) was loaded into the solid-phase extraction column. After loading the sample, the extraction column was washed with 6 mL of DCM. The purified solution was concentrated under a gentle high-purity nitrogen gas flow close to dryness and redissolved in 100 μL to obtain the eluate;

[0056] (3) The eluate obtained in step (2) is determined by a gas chromatography - quadrupole - electrostatic field ion orbitrap combined high - resolution mass spectrometer, and the conditions are as follows:

[0057] Gas chromatograph: GC 1610 from Thermo

[0058] The gas chromatography separation conditions are as follows: The chromatographic column is an Agilent DB - 5HT column (30m × 0.25mm × 0.25μm), and the separation is carried out with a helium gas flow rate of 1.2 mL / min. The temperature programming is as follows: The initial temperature is 40°C, held for 1 min, then increased to 240°C at a rate of 20°C / min, and subsequently increased to 300°C at a rate of 3°C / min and held for 5 min.

[0059] The high - resolution mass spectrometry conditions are as follows: Obitrap Exploris high - resolution mass spectrometer from Thermo; Ion source: EI; Carrier gas: High - purity helium gas (>99.99%); Data acquisition mode: Full Scan; Injection port temperature: 300°C;

[0060] Ionization mode: Positive ion mode; The ion source temperature and transfer line temperature are both 300°C, the ion source filament voltage is 70 eV; Scanning range m / z = 50 - 600; Trap offset is set to 2; Resolution is 60000;

[0061] According to the retention times, qualitative and quantitative ions of the liquid - phase monomer standards shown in Table 2, 88 liquid - phase monomer chromatographic peaks in the sediment are confirmed (as shown in Figure 1 ), Figure 1 The serial numbers in Figure 1 correspond to those in Table 2. And according to the standard curves of each liquid - phase monomer, the concentrations of each liquid - phase monomer in the sediment sample are confirmed through the peak areas of the chromatographic peaks in

[0062] Table 2: Retention times, qualitative and quantitative ion parameters of 88 liquid - phase monomers, recovery rates under spiked levels of 2, 10, and 50 ng, and the quantitative limit of the detection method

[0063]

[0064]

[0065]

[0066] As shown in Table 2, the recovery rates of 88 LCMs in the sediment are all between 78% and 106% (except that the recovery rate of VcHCP at low concentration is about 64%). The recovery rates of 2O5cHP and MePVbcH under a spiked level of 2 μg are 68% and 54% respectively, and their spiked performances are normal at 10 ng and 50 ng.

[0067] The above are only the preferred embodiments of the present invention and are 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 recorded in the foregoing embodiments or perform equivalent replacements on some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A high-throughput detection method for liquid crystal monomers in sediments, characterized in that It includes the following steps: (1) Use ultrasonic-assisted extraction to extract liquid crystal monomers from sediments, and obtain an extract after enrichment; (2) Use a solid-phase extraction cartridge to purify and remove impurities from the liquid crystal monomers in the extract to obtain an eluate; (3) Use a gas chromatography-quadrupole-electrostatic field ion orbitrap combined high-resolution mass spectrometer to measure the eluate obtained in step (2), and analyze the types and contents of liquid crystal monomers in the sediments according to the pre-established standard curve of liquid crystal monomers.

2. The high-throughput detection method of liquid crystal monomers in sediments according to claim 1, wherein In step (1), the sediments are marine sediments, river sediments or lake sediments.

3. The high-throughput detection method of liquid crystal monomers in sediments according to claim 1, wherein, In step (1), the extractants used in the ultrasonic-assisted extraction process are n-hexane and dichloromethane, and the extraction sequence is dichloromethane, dichloromethane / n-hexane.

4. The high-throughput detection method for liquid crystal monomers in sediments according to claim 1, characterized in that, In step (2), the solid-phase extraction cartridge is a Florisil solid-phase extraction column, and the loading flow rate of the solid-phase extraction cartridge is maintained at 3 - 4.5 mL / min.

5. The high-throughput detection method of liquid crystal monomers in sediments according to claim 1, wherein In step (2), the eluents used in the purification and impurity removal process are n-hexane and dichloromethane.

6. The high-throughput detection method of liquid crystal monomers in sediments according to claim 1, wherein In step (3), the gas chromatography-quadrupole-electrostatic field ion orbitrap combined high-resolution mass spectrometer uses a DB-5HT weak polar chromatographic column for chromatographic separation, and the specifications of the DB-5HT weak polar chromatographic column are 30 m × 0.25 mm × 0.25 μm.

7. The high-throughput detection method of liquid crystal monomers in sediments according to claim 1, wherein In step (3), the gas chromatography of the gas chromatography-quadrupole-electrostatic field ion orbitrap combined high-resolution mass spectrometer is separated with a helium gas flow rate of 1.2 mL / min. The temperature programming is that the initial temperature is 40 °C, held for 1 min, then increased to 240 °C at a rate of 20 °C / min, and then increased to 300 °C at a rate of 3 °C / min and held for 5 min.

8. The high-throughput detection method for liquid crystal monomers in sediments according to claim 1, characterized in that In step (3), the mass spectrometry conditions of the gas chromatography-quadrupole-electrostatic field ion orbitrap combined high-resolution mass spectrometer are: using an electron impact ionization source, the ionization mode is positive ion mode, the scanning mode is full scan mode, and the inlet temperature, transfer line temperature and ion source temperature are 300 °C.

9. The high-throughput detection method of liquid crystal monomers in sediments according to claim 1, characterized in that, The method for establishing the standard curve of the liquid crystal monomers is: prepare standard working solutions of the liquid crystal monomer standards with concentrations of 0.1 - 100 ng / L respectively, use a gas chromatography-quadrupole-electrostatic field ion orbitrap combined high-resolution mass spectrometer for detection, take the chromatographic peak area of the quantitative ion of the liquid crystal monomer as the ordinate and the corresponding liquid crystal monomer concentration as the abscissa to draw the standard curve.

10. The high-throughput detection method of liquid crystal monomers in sediments according to claim 1, wherein The liquid crystal monomers described above include 3VbcH, MeO3bcH, 2ObcH3, MeO3cHP, VcHCP, 2O3cHP, 2OdFP3cH, 2CB, 5VbcH, PecHCP, 5MeB, 3cHMeO-MeOdFP, 2OCB, 4cHCP, 3cH4OdFP, MeP2OPa, 2O5cHP, 4CB, 5cH2OdFP, 3cHCaAMeOP, 2BzoFCP, 2PMeOPa, 3OCB, 2bcHtFMeOP, 2bcHtFP, i5CB, 3cHCaA2OP, 2bcHdFP, 3BzoFCP, 3PMeOPa, tFPO-CF2-dF2B, 2cHdFB, 4OCB, tFMeO-3bcHP, 3bcHtFP, 3cHFtFB, MePVbcH, 3bcHdFP, 3cHtFB, 6CB, tFPO-CF2-dF3B, 3cHdFB, 3teFT, 5OCB, 4BzoCP, 7cHCP, 3tFT, BebcHdFP, 4bcHdFP, 7CB, 5BzodFCP, 5PMeOPa, 4cHtFPcHEt, 6OCB, 3Bzo5P, 5bcHtFP, BeOBzoCB, MePBebcH, 5bcHdFP, 5cHtFB, 5cHdFB, 7OCB, 3cH2B, 2OdFP3bcH, 9CB, 2F3T, 8OCB, 3cH3B, CBzo7P, 5Bzo5P, 5Bzo4OP, 9OCB, 5cH2B, 3CT, 5bcH2OdFP, 11CB, 10OCB, 12CB, 2bcHtFB, 3cHBzoCP, 4Bzo8OP, 5CT, 3bcHtFB, 4cHBzoFCP, 12OCB, 3bcHdFB, 5Bzo8OP and 3cHP3OPa.

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