Analysis method of carcinogenic polycyclic aromatic hydrocarbon in naphthenic lubricating oil

Abstract

The invention relates to the technical field of lubricating oil detection, in particular to a method for analyzing carcinogenic polycyclic aromatic hydrocarbon in naphthenic lubricating oil, which comprises the following steps: preparing a standard working solution of polycyclic aromatic hydrocarbon; the method comprises the following steps: extracting naphthenic lubricating oil by using dimethyl sulfoxide, and carrying out back extraction by using cyclohexane to obtain a solution to be detected; separating and detecting the standard working solution and the to-be-detected solution of the polycyclic aromatic hydrocarbon by adopting gas chromatography-mass spectrometry; a standard curve of the polycyclic aromatic hydrocarbon is obtained according to the detection result of the gas chromatography-mass spectrometry, and the polycyclic aromatic hydrocarbon in the to-be-detected solution is subjected to qualitative and quantitative determination by combining the standard curve of the polycyclic aromatic hydrocarbon. According to the method, 18 carcinogenic polycyclic aromatic hydrocarbons in the naphthenic lubricating oil are effectively separated and quantified, target peak matrix interference is reduced, qualitation and quantification are accurate, identification and quantification of the carcinogenic polycyclic aromatic hydrocarbons in the naphthenic lubricating oil sample are achieved, the method is easy to operate and implement, repeatability and reproducibility are good, and the method is suitable for industrial production. And the detection requirements of naphthenic base lubricating oil products are met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lubricating oil detection, and is an analysis method of carcinogenic polycyclic aromatic hydrocarbons in naphthenic base lubricating oil. BACKGROUND

[0002] In the field of petroleum industry, polycyclic aromatic hydrocarbons are important basic raw materials for organic chemical industry and widely exist in petroleum and its derivative products. Polycyclic aromatic hydrocarbons are a class of organic compounds containing two or more benzene rings in the molecular structure. The toxicity of different polycyclic aromatic hydrocarbons varies with the type and structure of the polycyclic aromatic hydrocarbons. Most of them have the characteristics of teratogenicity, carcinogenicity, mutagenicity and biological recalcitrance. They are the earliest discovered environmental carcinogens. Some of them are easily absorbed through the skin and inhaled through the lungs, which can easily induce serious diseases such as skin cancer, lung cancer and stomach cancer, and pose potential hazards to the environment and human health. They are toxic organic pollutants that many countries prefer to control. Two essential raw materials, carbon black and filling oil, in rubber products contain polycyclic aromatic hydrocarbons. At present, the tire rubber industry mainly focuses on the control of the content of 18 kinds of polycyclic aromatic hydrocarbons, including naphthalene, acenylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benz(a)anthracene, chrysene, benzo[b]fluoranthene, benzo[j]fluoranthene, benzo[k]fluoranthene, benz(a)pyrene, benz(e)pyrene, indeno[1,2,3-cd]pyrene, dibenzo[a,h]anthracene and benz[g,h,i]perylene. Naphthenic base oil, as rubber filling oil, has the characteristics of light color, good light resistance, good oxidation resistance and good compatibility with rubber, and is widely used in domestic synthetic rubber production enterprises. Therefore, it is an important work to detect the content of carcinogenic polycyclic aromatic hydrocarbons in naphthenic base oil.

[0003] At present, the commonly used method for detecting carcinogenic polycyclic aromatic hydrocarbons is gas chromatography-mass spectrometry (GC / MS). Due to the complexity of the sample and the diversity of the structure of polycyclic aromatic hydrocarbons, some carcinogenic polycyclic aromatic hydrocarbons have high similarity in structure. Different sample types require different pretreatment methods. Before GC / MS analysis, the sample needs to be pretreated, such as extraction, purification and concentration, to remove interfering substances and concentrate target analytes. Then, GC / MS is applied to identify and quantitatively analyze the sample through the characteristic peaks of mass spectrometry.

[0004] Due to the characteristics of typical large peak package of naphthenic base oil chromatogram, the target peak is interfered by other components, and overlapping peaks may occur, which affects the integration of peak area and thus affects the final content of target polycyclic aromatic hydrocarbons. The existing technology has the problems of large matrix interference of target peaks in GC / MS selected ion chromatogram, peak overlapping, poor differentiation of target peaks and inaccurate qualitative analysis.

[0005] At present, there is no related report on the determination of carcinogenic polycyclic aromatic hydrocarbons in naphthenic base lubricating oil. SUMMARY

[0006] The application provides a method for analyzing carcinogenic polycyclic aromatic hydrocarbons in naphthenic base lubricating oil, which overcomes the defects of the prior art and effectively solves the problems of large matrix interference and inaccurate qualitative and quantitative determination of polycyclic aromatic hydrocarbons in naphthenic base lubricating oil.

[0007] The technical scheme of the application is achieved by the following method for analyzing carcinogenic polycyclic aromatic hydrocarbons in naphthenic base lubricating oil, which comprises the following steps: Preparation of a standard working solution of polycyclic aromatic hydrocarbons; Extraction of the naphthenic base lubricating oil with dimethyl sulfoxide and back extraction with cyclohexane to obtain a test solution; Separation and detection of the standard working solution of polycyclic aromatic hydrocarbons and the test solution by gas chromatography-mass spectrometry; Obtaining of a standard curve of polycyclic aromatic hydrocarbons according to the detection results of gas chromatography-mass spectrometry, and qualitative and quantitative determination of polycyclic aromatic hydrocarbons in the test solution in combination with the standard curve of polycyclic aromatic hydrocarbons.

[0008] The following is a further optimization or / and improvement of the above technical scheme: The quantitative determination of the content of polycyclic aromatic hydrocarbons in the test solution is performed by an internal standard method, and the internal standard is one or more of dodecadeuterated perylene, benzo(a)anthracene deuterium twelve, benzo(b)fluoranthene deuterium twelve and benzo(a)pyrene deuterium twelve.

[0009] The extraction of the naphthenic base lubricating oil with dimethyl sulfoxide and the back extraction with cyclohexane comprise the following steps: Firstly, a required amount of naphthenic base lubricating oil sample is taken and dissolved in cyclohexane to obtain a sample solution; Secondly, dimethyl sulfoxide is added to the sample solution, and after extraction, a dimethyl sulfoxide extract is obtained; Thirdly, sodium chloride solution and cyclohexane are added to the dimethyl sulfoxide extract for back extraction, and after washing of the extract, a test solution is obtained.

[0010] The number of extraction and back extraction is 2 to 4 times.

[0011] In the first step, the sampling amount of naphthenic base lubricating oil is 0.05 g to 1 g.

[0012] In the second step, the amount of dimethyl sulfoxide used for single extraction is 8 ml to 12 ml.

[0013] In the third step, the amount of cyclohexane used for single back extraction is 5 ml to 10 ml, the amount of sodium chloride solution is 60 ml to 90 ml, and the mass concentration of the sodium chloride solution is 4% to 6%.

[0014] In the third step above, the washing of the extract includes: adding 5 ml to 10 ml of sodium chloride solution at 70°C to the cyclohexane extract obtained by back-extraction and washing twice.

[0015] The chromatographic conditions for the above gas chromatography-mass spectrometry detection are as follows: the column is a non-polar or weakly polar column with a length of 30 m to 60 m and a diameter of 0.25 mm to 0.5 mm; the injection port temperature is 270 °C to 300 °C; splitless injection is used; the carrier gas is helium; and the temperature program is as follows: starting at 35 °C to 50 °C, increasing to 310 °C, and holding until all components elute; the heating rate is 5 °C / min to 15 °C / min.

[0016] The mass spectrometry conditions for the above gas chromatography-mass spectrometry detection are as follows: GC / MS interface temperature is 270℃ to 300℃, mass spectrometry scan range is 30amu to 500amu, electron impact ionization energy is 70eV to 90eV, EI ion source temperature is 260℃ to 300℃, and the determination mode is selected ion detection mode.

[0017] The analytical method for carcinogenic polycyclic aromatic hydrocarbons in naphthenic lubricating oils of the present invention effectively separates and quantifies 18 carcinogenic polycyclic aromatic hydrocarbons in naphthenic lubricating oils, reduces matrix interference of target peaks, and provides accurate qualitative and quantitative results. It enables the identification and quantification of carcinogenic polycyclic aromatic hydrocarbons in naphthenic lubricating oil samples. The method is simple to operate and easy to implement, with good repeatability and reproducibility, meeting the needs of naphthenic lubricating oil product testing. Attached Figure Description

[0018] Appendix Figure 1 This is the total ion current chromatogram of Example 20 of the present invention.

[0019] Appendix Figure 2 This is the total ion current chromatogram of Comparative Example 1 in this invention.

[0020] Appendix Figure 3 This is a selected ion chromatogram of some of the target carcinogenic polycyclic aromatic hydrocarbons in Example 20 of the present invention.

[0021] Appendix Figure 4 This is a selected ion chromatogram of some of the target carcinogenic polycyclic aromatic hydrocarbons in Example 20 of the present invention. Detailed Implementation

[0022] This invention is not limited to the following embodiments, and specific implementation methods can be determined according to the technical solution of this invention and the actual situation. Unless otherwise specified, all chemical reagents and chemical products mentioned in this invention are well-known and commonly used chemical reagents and chemical products in the prior art; unless otherwise specified, all percentages in this invention are mass percentages; room temperature in this invention generally refers to a temperature between 15°C and 25°C, and is generally defined as 25°C.

[0023] The application will be further described in connection with the following examples: Example 1: The analysis method of carcinogenic polycyclic aromatic hydrocarbons in naphthenic base lubricating oil, comprising the following steps: Preparation of standard working solution of polycyclic aromatic hydrocarbons; Extraction of naphthenic base lubricating oil with dimethyl sulfoxide and back extraction with cyclohexane to obtain the test solution; Separation and detection of standard working solution of polycyclic aromatic hydrocarbons and test solution by gas chromatography-mass spectrometry; Obtaining of standard curve of polycyclic aromatic hydrocarbons according to the detection results of gas chromatography-mass spectrometry, and qualitative and quantitative determination of polycyclic aromatic hydrocarbons in test solution combined with the standard curve of polycyclic aromatic hydrocarbons.

[0024] Example 2: As an optimization of the above example, the quantitative determination of the content of polycyclic aromatic hydrocarbons in the test solution uses an internal standard method, and the internal standard is one or more of dodecadeuterated perylene, benzo(a) anthracene deuterium twelve, benzo(b) fluoranthene deuterium twelve and benzo(a) pyrene deuterium twelve.

[0025] Example 3: As an optimization of the above example, the operation steps of extraction of naphthenic base lubricating oil with dimethyl sulfoxide and back extraction with cyclohexane include: First step: taking a required amount of naphthenic base lubricating oil sample, adding cyclohexane for dissolution to obtain a sample solution; Second step: adding dimethyl sulfoxide to the sample solution, and after extraction, obtaining a dimethyl sulfoxide extract solution; Third step: adding sodium chloride solution and cyclohexane to the dimethyl sulfoxide extract solution for back extraction, and after washing the extract solution, obtaining a test solution.

[0026] Example 4: As an optimization of the above example, the number of extraction and back extraction is 2 to 4 times.

[0027] Example 5: As an optimization of the above example, in the first step, the sampling amount of naphthenic base lubricating oil is 0.05 g to 1 g.

[0028] Example 6: As an optimization of the above example, in the second step, the amount of dimethyl sulfoxide used for single extraction is 8 ml to 12 ml.

[0029] Example 7: As an optimization of the above example, in the third step, the amount of cyclohexane used for single back extraction is 5 ml to 10 ml, the amount of sodium chloride solution is 60 ml to 90 ml, and the mass concentration of sodium chloride solution is 4% to 6%.

[0030] As an optimization of the above-mentioned embodiments, in the third step, the washing of the extract solution comprises: adding 5ml to 10ml of a sodium chloride solution with a temperature of 65℃ to 80℃ to the cyclohexane extract obtained by back extraction for washing twice. After the washing is completed, the water layer is discarded, and the cyclohexane extract is blown dry with nitrogen, concentrated by a hot plate method or a sample concentrator as needed, and then the volume is adjusted to obtain the solution to be detected.

[0031] As an optimization of the above-mentioned embodiments, the chromatographic conditions of the gas chromatography-mass spectrometry detection are as follows: the chromatographic column is a non-polar chromatographic column or a weakly polar chromatographic column, the column length is 30m to 60m, the diameter is 0.25mm to 0.5mm, the injection port temperature is 270℃ to 300℃, the injection is not split, the carrier gas is helium, and the temperature programming is as follows: the initial temperature is 35℃ to 50℃, and then increased to 310℃, and kept until all components flow out, and the temperature increasing speed is 5℃ / min to 15℃ / min.

[0032] As an optimization of the above-mentioned embodiments, the mass spectrometry conditions of the gas chromatography-mass spectrometry detection are as follows: the GC / MS interface temperature is 270℃ to 300℃, the mass spectrometry scanning range is 30amu to 500amu, the electron impact ionization energy is 70eV to 90eV, the EI ion source temperature is 260℃ to 300℃, and the determination mode is the selected ion monitoring mode.

[0033] This invention extracts, separates, and quantifies 18 carcinogenic polycyclic aromatic hydrocarbons (PAHs) in naphthenic lubricating oils. The 18 carcinogenic PAHs are naphthalene, acenaphthene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo[a]anthracene, β-phenanthracene, benzo[b]fluoranthene, benzo[j]fluoranthene, benzo[k]fluoranthene, benzo[e]pyrene, benzo[a]pyrene, indo[1,2,3-cd]pyrene, dibenzo[a,h]anthracene, and benzo[g,h,i]perylene. This invention identifies and quantifies carcinogenic PAHs in naphthenic lubricating oil samples. The sample solution is extracted using liquid-liquid extraction to first separate fused-ring aromatics, then further separates the target carcinogenic PAHs. Gas chromatography-mass spectrometry (GC / MS) is used to separate and identify the target PAHs, and internal standard method is used for quantification. The extraction process uses dimethyl sulfoxide (DMSO) as the extractant, which can extract all polycyclic aromatic hydrocarbons (PAHs) in the oil. The target carcinogenic PAHs are a subset of PHAs, leading to significant matrix interference. To address this issue, this invention reduces matrix interference by adjusting the sample volume and improves gas chromatography-mass spectrometry (GC / MS) conditions, making the target compounds easier to separate clearly. Furthermore, this invention uses GC / MS in selective ion detection mode to obtain the total ion chromatogram of the PAHs to be tested. By extracting the characteristic ions of each individual target PAH, a selected ion chromatogram of each PAH is obtained. Using internal standards with different peak positions further improves the accuracy of qualitative and quantitative identification of the 18 target carcinogenic PAHs. Compared with existing PAH detection technologies, this invention solves the problems of large matrix interference, peak overlap, poor distinction between target peaks, and inaccurate qualitative identification in GC / MS selected ion chromatograms during the detection of naphthenic lubricating oils, enabling the identification and quantification of carcinogenic PAHs in naphthenic lubricating oil samples.

[0034] Example 11: Weigh 0.07g of cycloalkyl lubricating oil sample, add 8ml of cyclohexane to dissolve evenly, add 10ml of dimethyl sulfoxide to extract the sample solution, shake vigorously for 2min, and let stand to separate the layers. Take the upper extract, and repeat the extraction of the lower residual liquid with 10ml of dimethyl sulfoxide. Combine the extracts. Add 70ml of 4% sodium chloride solution to the dimethyl sulfoxide extract to reduce its solubility, then add 5ml of cyclohexane for back-extraction, shake vigorously for 2min, and let stand to separate the layers. Collect the upper extract, and extract the lower aqueous phase again with 5ml of cyclohexane. Combine the extracts. Wash the cyclohexane extract twice with 5ml of 70℃ hot sodium chloride solution, discard the aqueous layer, and concentrate the cyclohexane extract using a rotary evaporator (rotary evaporation operating conditions: rotation speed 100rpm to 120rpm, temperature less than or equal to 70℃, pressure set to 450mmHg to evaporate the solvent, then reduce the pressure to evaporate the solvent completely). Make up the volume with cyclohexane to 1ml for analysis.

[0035] 1 μl of dodecadeuterium perylene of known concentration was added as an internal standard, and the analyte solution was detected by GC / MS to obtain a selected ion chromatogram of the polycyclic aromatic hydrocarbons (PAHs). Chromatographic conditions: Nonpolar 30 m × 0.25 mm × 0.1 μm column; injection port temperature 280 °C; carrier gas: helium; splitless injection; temperature program: starting at 35 °C, increasing to 310 °C at a rate of 5 °C / min, and holding until all components elute. Mass spectrometry conditions: GC / MS interface temperature 280 °C; mass spectrum scan range 30 amu to 500 amu; electron impact ionization energy 70 eV; EI ion source temperature 280 °C; acquisition mode: selected ion detection.

[0036] Selected ion chromatograms of each target carcinogenic polycyclic aromatic hydrocarbon were obtained in a GC / MS workstation. Qualitative and quantitative analysis of each polycyclic aromatic hydrocarbon in the naphthenic lubricating oil sample was performed, and the quantitative results are shown in Table 1.

[0037] Example 12: Weigh 0.2g of cycloalkyl lubricating oil sample, add 8ml of cyclohexane to dissolve evenly, add 10ml of dimethyl sulfoxide to extract the sample solution, shake vigorously for 2min, and let stand to separate the layers. Collect the upper extract, and repeat the extraction of the lower residual liquid with 10ml of dimethyl sulfoxide. Combine the extracts. Add 70ml of 4% sodium chloride solution to the dimethyl sulfoxide extract to reduce its solubility, then add 5ml of cyclohexane for back-extraction, shake vigorously for 2min, and let stand to separate the layers. Collect the upper extract, and extract the lower aqueous phase again with 5ml of cyclohexane. Combine the extracts. Wash the cyclohexane extract twice with 5ml of 70℃ hot sodium chloride solution, discard the aqueous layer, concentrate the cyclohexane extract using a rotary evaporator, and bring the volume to 1ml with cyclohexane for analysis.

[0038] 1 μl of dodecadeuterium perylene of known concentration was added as an internal standard, and the analyte solution was detected by GC / MS to obtain a selected ion chromatogram of the polycyclic aromatic hydrocarbons (PAHs). Chromatographic conditions: Nonpolar 30 m × 0.25 mm × 0.1 μm column; injection port temperature 280 °C; carrier gas: helium; splitless injection; temperature program: starting at 35 °C, increasing to 310 °C at a rate of 5 °C / min, and holding until all components elute. Mass spectrometry conditions: GC / MS interface temperature 280 °C; mass spectrum scan range 30 amu to 500 amu; electron impact ionization energy 70 eV; EI ion source temperature 280 °C; acquisition mode: selected ion detection.

[0039] Selected ion chromatograms of each target carcinogenic polycyclic aromatic hydrocarbon were obtained in a GC / MS workstation. Qualitative and quantitative analysis of each polycyclic aromatic hydrocarbon in the naphthenic lubricating oil sample was performed, and the quantitative results are shown in Table 1.

[0040] Example 13: Weigh 0.5g of cycloalkyl lubricating oil sample, add 10ml of cyclohexane to dissolve evenly, add 12ml of dimethyl sulfoxide to extract the sample solution, shake vigorously for 2min, and let stand to separate the layers. Collect the upper extract, and repeat the extraction of the lower residual liquid with 12ml of dimethyl sulfoxide. Combine the extracts. Add 70ml of 4% sodium chloride solution to the dimethyl sulfoxide extract to reduce its solubility, then add 5ml of cyclohexane for back-extraction, shake vigorously for 2min, and let stand to separate the layers. Collect the upper extract, and extract the lower aqueous phase again with 5ml of cyclohexane. Combine the extracts. Wash the cyclohexane extract twice with 5ml of 70℃ hot sodium chloride solution, discard the aqueous layer, concentrate the cyclohexane extract using a rotary evaporator, and bring the volume to 1ml with cyclohexane for analysis.

[0041] A mixed solution of dodecyl perylene and benzo(a)anthracene deuterated dodecylene of known concentration was added as an internal standard. The analyte solution was detected by GC / MS to obtain a selected ion chromatogram of the polycyclic aromatic hydrocarbons (PAHs). Chromatographic conditions: Nonpolar 30m × 0.25mm × 0.1μm column; injection port temperature 280℃; carrier gas: helium; splitless injection; temperature program: starting at 35℃, increasing to 310℃ at a rate of 5℃ / min, and holding until all components elute. Mass spectrometry conditions: GC / MS interface temperature 280℃; mass spectrum scan range 30amu to 500amu; electron impact ionization energy 70eV; EI ion source temperature 280℃; acquisition mode: selected ion detection.

[0042] Selected ion chromatograms of each target carcinogenic polycyclic aromatic hydrocarbon were obtained in a GC / MS workstation. Qualitative and quantitative analysis of each polycyclic aromatic hydrocarbon in the naphthenic lubricating oil sample was performed, and the quantitative results are shown in Table 1.

[0043] Example 14: Weigh 1.0 g of cycloalkyl lubricating oil sample, add 12 ml of cyclohexane to dissolve evenly, add 12 ml of dimethyl sulfoxide to extract the sample solution, shake vigorously for 2 min, and allow to stand for separation. Collect the upper extract, and repeat the extraction of the lower residual liquid with 12 ml of dimethyl sulfoxide. Combine the extracts. Add 70 ml of 4% sodium chloride solution to the dimethyl sulfoxide extract to reduce its solubility, then add 5 ml of cyclohexane for back-extraction, shake vigorously for 2 min, and allow to stand for separation. Collect the upper extract, and extract the lower aqueous phase again with 5 ml of cyclohexane. Combine the extracts. Wash the cyclohexane extract twice with 5 ml of 70°C hot sodium chloride solution, discard the aqueous layer, concentrate the cyclohexane extract using a rotary evaporator, and bring the volume to 1 ml for analysis.

[0044] A mixed solution of dodecyl perylene and benzo(a)anthracene deuterated dodecylene of known concentration was added as an internal standard. The analyte solution was detected by GC / MS to obtain a selected ion chromatogram of the polycyclic aromatic hydrocarbons (PAHs). Chromatographic conditions: Nonpolar 30m × 0.25mm × 0.1μm column; injection port temperature 280℃; carrier gas: helium; splitless injection; temperature program: starting at 35℃, increasing to 310℃ at a rate of 5℃ / min, and holding until all components elute. Mass spectrometry conditions: GC / MS interface temperature 280℃; mass spectrum scan range 30amu to 500amu; electron impact ionization energy 70eV; EI ion source temperature 280℃; acquisition mode: selected ion detection.

[0045] Selected ion chromatograms of each target carcinogenic polycyclic aromatic hydrocarbon were obtained in a GC / MS workstation. Qualitative and quantitative analysis of each polycyclic aromatic hydrocarbon in the naphthenic lubricating oil sample was performed, and the quantitative results are shown in Table 1.

[0046] Example 15: Weigh 0.07g of cycloalkyl lubricating oil sample, add 8ml of cyclohexane to dissolve evenly, add 10ml of dimethyl sulfoxide to extract the sample solution, shake vigorously for 2min, and allow to stand for separation. Collect the upper extract, and repeat the extraction of the lower residual liquid with 10ml of dimethyl sulfoxide. Combine the extracts. Add 70ml of 4% sodium chloride solution to the dimethyl sulfoxide extract to reduce its solubility, then add 5ml of cyclohexane for back-extraction, shake vigorously for 2min, and allow to stand for separation. Collect the upper extract, and extract the lower aqueous phase again with 5ml of cyclohexane. Combine the extracts. Wash the cyclohexane extract twice with 5ml of 70℃ hot sodium chloride solution, discard the aqueous layer, concentrate the cyclohexane extract using a rotary evaporator, and bring the volume to 1ml with cyclohexane for analysis.

[0047] A mixed solution of dodecyl perylene and benzo(a)anthracene deuterated dodecylene of known concentration was added as an internal standard. The analyte solution was detected by GC / MS to obtain a selected ion chromatogram of the polycyclic aromatic hydrocarbons (PAHs). Chromatographic conditions: Nonpolar 30m × 0.25mm × 0.1μm column; injection port temperature 280℃; carrier gas: helium; splitless injection; temperature program: starting at 35℃, increasing to 310℃ at a rate of 10℃ / min, and holding until all components elute. Mass spectrometry conditions: GC / MS interface temperature 280℃; mass spectrum scan range 30amu to 500amu; electron impact ionization energy 70eV; EI ion source temperature 280℃; acquisition mode: selected ion detection.

[0048] Selected ion chromatograms of each target carcinogenic polycyclic aromatic hydrocarbon were obtained in a GC / MS workstation. Qualitative and quantitative analysis of each polycyclic aromatic hydrocarbon in the naphthenic lubricating oil sample was performed, and the quantitative results are shown in Table 1.

[0049] Example 16: Weigh 0.07g of cycloalkyl lubricating oil sample, add 8ml of cyclohexane to dissolve evenly, add 10ml of dimethyl sulfoxide to extract the sample solution, shake vigorously for 2min, and allow to stand for separation. Collect the upper extract, and repeat the extraction of the lower residual liquid with 10ml of dimethyl sulfoxide. Combine the extracts. Add 70ml of 4% sodium chloride solution to the dimethyl sulfoxide extract to reduce its solubility, then add 5ml of cyclohexane for back-extraction, shake vigorously for 2min, and allow to stand for separation. Collect the upper extract, and extract the lower aqueous phase again with 5ml of cyclohexane. Combine the extracts. Wash the cyclohexane extract twice with 5ml of 70℃ hot sodium chloride solution, discard the aqueous layer, concentrate the cyclohexane extract using a rotary evaporator, and bring the volume to 1ml with cyclohexane for analysis.

[0050] Add 1 μl of a known concentration of a mixed solution of benzo(a) anthracene deuterondodecyl and benzo(b) fluoranthene deuterondodecyl, and add 1 μl of dodeuterium perylene as an internal standard. GC / MS was used to detect the analyte solution, yielding a selected ion chromatogram of the polycyclic aromatic hydrocarbons (PAHs). Chromatographic conditions: Nonpolar 30m × 0.25mm × 0.1μm column; injection port temperature 280℃; carrier gas: helium; splitless injection; temperature program: starting at 35℃, increasing to 310℃ at a rate of 15℃ / min, and holding until all components elute. Mass spectrometry conditions: GC / MS interface temperature 280℃; mass spectrum scan range 30 amu to 500 amu; electron impact ionization energy 70 eV; EI ion source temperature 280℃; acquisition mode: selected ion detection.

[0051] Selected ion chromatograms of each target carcinogenic polycyclic aromatic hydrocarbon were obtained in a GC / MS workstation. Qualitative and quantitative analysis of each polycyclic aromatic hydrocarbon in the naphthenic lubricating oil sample was performed, and the quantitative results are shown in Table 1.

[0052] Example 17: Weigh 0.5g of cycloalkyl lubricating oil sample, add 10ml of cyclohexane to dissolve evenly, add 10ml of dimethyl sulfoxide to extract the sample solution, shake vigorously for 2min, and let stand to separate the layers. Collect the upper extract, and repeat the extraction of the lower residual liquid with 10ml of dimethyl sulfoxide. Combine the extracts. Add 70ml of 4% sodium chloride solution to the dimethyl sulfoxide extract to reduce its solubility, then add 5ml of cyclohexane for back-extraction, shake vigorously for 2min, and let stand to separate the layers. Collect the upper extract, and extract the lower aqueous phase again with 5ml of cyclohexane. Combine the extracts. Wash the cyclohexane extract twice with 5ml of 70℃ hot sodium chloride solution, discard the aqueous layer, concentrate the cyclohexane extract using a rotary evaporator, and bring the volume to 1ml with cyclohexane for analysis.

[0053] 1 μL of benzo(a)anthracene deuterondecadodecyl and benzo(b)fluoranthracene deuterondecadodecyl were added as internal standards. The analyte solution was detected by GC / MS to obtain a selected ion chromatogram of the polycyclic aromatic hydrocarbons (PAHs). Chromatographic conditions: Nonpolar 30m × 0.25mm × 0.1μm column; injection port temperature 280℃; carrier gas: helium; splitless injection; temperature program: starting at 50℃, increasing to 310℃ at a rate of 10℃ / min, and holding until all components elute. Mass spectrometry conditions: GC / MS interface temperature 280℃; mass spectrum scan range 30 amu to 500 amu; electron impact ionization energy 70 eV; EI ion source temperature 280℃; acquisition mode: selected ion detection.

[0054] Selected ion chromatograms of each target carcinogenic polycyclic aromatic hydrocarbon were obtained in a GC / MS workstation. Qualitative and quantitative analysis of each polycyclic aromatic hydrocarbon in the naphthenic lubricating oil sample was performed, and the quantitative results are shown in Table 1.

[0055] Example 18: Weigh 1.0 g of cycloalkyl lubricating oil sample, add 12 ml of cyclohexane to dissolve evenly, add 12 ml of dimethyl sulfoxide to extract the sample solution, shake vigorously for 2 min, and allow to stand for separation. Collect the upper extract, and repeat the extraction of the lower residual liquid with 12 ml of dimethyl sulfoxide. Combine the extracts. Add 70 ml of 4% sodium chloride solution to the dimethyl sulfoxide extract to reduce its solubility, then add 5 ml of cyclohexane for back-extraction. Shake vigorously for 2 min, and allow to stand for separation. Collect the upper extract, and extract the lower aqueous phase again with 5 ml of cyclohexane. Combine the extracts. Wash the cyclohexane extract twice with 5 ml of 70°C hot sodium chloride solution, discard the aqueous layer, concentrate the cyclohexane extract using a rotary evaporator, and bring the volume to 1 ml for analysis.

[0056] 1 μl of benzo(a)anthracene deuterondecadodecyl and benzo(b)fluoranthracene deuterondecadodecyl were added as internal standards. The analyte solution was detected by GC / MS to obtain a selected ion chromatogram of the polycyclic aromatic hydrocarbons (PAHs). Chromatographic conditions: Nonpolar 30 m × 0.38 mm × 0.1 μm column; injection port temperature 280 °C; carrier gas: helium; splitless injection; temperature program: starting at 50 °C, increasing to 310 °C at a rate of 15 °C / min, and holding until all components elute. Mass spectrometry conditions: GC / MS interface temperature 280 °C; mass spectrum scan range 30 amu to 500 amu; electron impact ionization energy 70 eV; EI ion source temperature 280 °C; acquisition mode: selected ion detection.

[0057] Selected ion chromatograms of each target carcinogenic polycyclic aromatic hydrocarbon were obtained in a GC / MS workstation. Qualitative and quantitative analysis of each polycyclic aromatic hydrocarbon in the naphthenic lubricating oil sample was performed, and the quantitative results are shown in Table 1.

[0058] Example 19: Weigh 0.5g of cycloalkyl lubricating oil sample, add 10ml of cyclohexane to dissolve evenly, add 10ml of dimethyl sulfoxide to extract the sample solution, shake vigorously for 2min, and let stand to separate the layers. Collect the upper extract, and repeat the extraction of the lower residual liquid with 10ml of dimethyl sulfoxide. Combine the extracts. Add 70ml of 4% sodium chloride solution to the dimethyl sulfoxide extract to reduce its solubility, then add 5ml of cyclohexane for back-extraction, shake vigorously for 2min, and let stand to separate the layers. Collect the upper extract, and extract the lower aqueous phase again with 5ml of cyclohexane. Combine the extracts. Wash the cyclohexane extract twice with 5ml of 70℃ hot sodium chloride solution, discard the aqueous layer, concentrate the cyclohexane extract using a rotary evaporator, and bring the volume to 1ml with cyclohexane for analysis.

[0059] 1 μl of benzo(a)anthracene deuterondecadodecyl and benzo(b)fluoranthracene deuterondecadodecyl were added as internal standards. The analyte solution was detected by GC / MS to obtain a selected ion chromatogram of the polycyclic aromatic hydrocarbons (PAHs). Chromatographic conditions: Nonpolar 30 m × 0.38 mm × 0.1 μm column; injection port temperature 280 °C; carrier gas: helium; splitless injection; temperature program: starting at 50 °C, increasing to 310 °C at a rate of 10 °C / min, and holding until all components elute. Mass spectrometry conditions: GC / MS interface temperature 280 °C; mass spectrum scan range 30 amu to 500 amu; electron impact ionization energy 70 eV; EI ion source temperature 280 °C; acquisition mode: selected ion detection.

[0060] Selected ion chromatograms of each target carcinogenic polycyclic aromatic hydrocarbon were obtained in a GC / MS workstation. Qualitative and quantitative analysis of each polycyclic aromatic hydrocarbon in the naphthenic lubricating oil sample was performed, and the quantitative results are shown in Table 1.

[0061] Example 20: Weigh 0.2g of cycloalkyl lubricating oil sample, add 10ml of cyclohexane to dissolve evenly, add 10ml of dimethyl sulfoxide to extract the sample solution, shake vigorously for 2min, and let stand to separate the layers. Collect the upper extract, and repeat the extraction of the lower residual liquid with 10ml of dimethyl sulfoxide. Combine the extracts. Add 70ml of 4% sodium chloride solution to the dimethyl sulfoxide extract to reduce its solubility, then add 5ml of cyclohexane for back-extraction, shake vigorously for 2min, and let stand to separate the layers. Collect the upper extract, and extract the lower aqueous phase again with 5ml of cyclohexane. Combine the extracts. Wash the cyclohexane extract twice with 5ml of 70℃ hot sodium chloride solution, discard the aqueous layer, concentrate the cyclohexane extract using a rotary evaporator, and bring the volume to 1ml with cyclohexane for analysis.

[0062] 1 μl of benzo(a)anthracene deuterondecadodecyl and benzo(b)fluoranthracene deuterondecadodecyl were added as internal standards. The analyte solution was detected by GC / MS to obtain a selected ion chromatogram of the polycyclic aromatic hydrocarbons (PAHs). Chromatographic conditions: Nonpolar 30 m × 0.38 mm × 0.1 μm column; injection port temperature 280 °C; carrier gas: helium; splitless injection; temperature program: starting at 35 °C, increasing to 310 °C at a rate of 5 °C / min, and holding until all components elute. Mass spectrometry conditions: GC / MS interface temperature 280 °C; mass spectrum scan range 30 amu to 500 amu; electron impact ionization energy 70 eV; EI ion source temperature 280 °C; acquisition mode: selected ion detection.

[0063] Selected ion chromatograms of each target carcinogenic polycyclic aromatic hydrocarbon were obtained using a GC / MS workstation. Qualitative and quantitative analyses were performed on the various polycyclic aromatic hydrocarbons in the naphthenic lubricating oil samples, and the quantitative results are shown in Table 2. The selected ion chromatograms of the 18 target carcinogenic polycyclic aromatic hydrocarbons in this example are shown in Table 2. Figure 3 and Figure 4 , Figure 3 and Figure 4 In the table, 1 is naphthalene, 2 is acenaphthene, 3 is acenaphthene, 4 is fluorene, 5 is phenanthrene, 6 is anthracene, 7 is fluoranthene, 8 is pyrene, 9 is benzo(a)anthene, 10 is α, 11 is benzo[b]fluoranthene, 12 is benzo[j]fluoranthene, 13 is benzo[k]fluoranthene, 14 is benzo[e]pyrene, 15 is benzo[a]pyrene, 16 is indo[1,2,3-cd]pyrene, 17 is dibenzo[a,h]anthene, and 18 is benzo[g,h,i]perylene. The quantitative ions and retention times of the 18 carcinogenic polycyclic aromatic hydrocarbons are shown in Table 3.

[0064] Example 21: Weigh 0.2g of cycloalkyl lubricating oil sample, add 10ml of cyclohexane to dissolve evenly, add 10ml of dimethyl sulfoxide to extract the sample solution, shake vigorously for 2min, and let stand to separate the layers. Collect the upper extract, and repeat the extraction of the lower residual liquid with 10ml of dimethyl sulfoxide. Combine the extracts. Add 70ml of 4% sodium chloride solution to the dimethyl sulfoxide extract to reduce its solubility, then add 5ml of cyclohexane for back-extraction, shake vigorously for 2min, and let stand to separate the layers. Collect the upper extract, and extract the lower aqueous phase again with 5ml of cyclohexane. Combine the extracts. Wash the cyclohexane extract twice with 5ml of 70℃ hot sodium chloride solution, discard the aqueous layer, concentrate the cyclohexane extract using a rotary evaporator, and bring the volume to 1ml with cyclohexane for analysis.

[0065] 1 μl of benzo(a)anthracene deuterondecadodecyl, benzo(b)fluoranthracene deuterondecadodecyl, and benzo(a)pyrene deuterondecadodecyl were added as internal standards. The analyte solution was analyzed by GC / MS to obtain a selected ion chromatogram of the polycyclic aromatic hydrocarbons (PAHs). Chromatographic conditions: Nonpolar 30 m × 0.38 mm × 0.1 μm column; injection port temperature 280 °C; carrier gas: helium; splitless injection; temperature program: starting at 35 °C, increasing to 310 °C at a rate of 5 °C / min, and holding until all components elute. Mass spectrometry conditions: GC / MS interface temperature 280 °C; mass spectrum scan range 30 amu to 500 amu; electron impact ionization energy 70 eV; EI ion source temperature 280 °C; acquisition mode: selected ion detection.

[0066] Selected ion chromatograms of each target carcinogenic polycyclic aromatic hydrocarbon were obtained in a GC / MS workstation. Qualitative and quantitative analysis of each polycyclic aromatic hydrocarbon in the naphthenic lubricating oil sample was performed, and the quantitative results are shown in Table 2.

[0067] Example 22: Weigh 0.07g of cycloalkyl lubricating oil sample, add 8ml of cyclohexane to dissolve evenly, add 10ml of dimethyl sulfoxide to extract the sample solution, shake vigorously for 2min, and allow to stand for separation. Collect the upper extract, and repeat the extraction of the lower residual liquid with 10ml of dimethyl sulfoxide. Combine the extracts. Add 70ml of 4% sodium chloride solution to the dimethyl sulfoxide extract to reduce its solubility, then add 5ml of cyclohexane for back-extraction, shake vigorously for 2min, and allow to stand for separation. Collect the upper extract, and extract the lower aqueous phase again with 5ml of cyclohexane. Combine the extracts. Wash the cyclohexane extract twice with 5ml of 70℃ hot sodium chloride solution, discard the aqueous layer, concentrate the cyclohexane extract using a rotary evaporator, and bring the volume to 1ml for analysis.

[0068] 1 μl of benzo(a)anthracene deuterondecadodecyl, benzo(b)fluoranthracene deuterondecadodecyl, and benzo(a)pyrene deuterondecadodecyl were added as internal standards. The analyte solution was analyzed by GC / MS to obtain a selected ion chromatogram of the polycyclic aromatic hydrocarbons (PAHs). Chromatographic conditions: Nonpolar 60 m × 0.25 mm × 0.1 μm column; injection port temperature 280 °C; carrier gas: helium; splitless injection; temperature program: starting at 35 °C, increasing to 310 °C at a rate of 5 °C / min, and holding until all components elute. Mass spectrometry conditions: GC / MS interface temperature 280 °C; mass spectrum scan range 30 amu to 500 amu; electron impact ionization energy 70 eV; EI ion source temperature 280 °C; acquisition mode: selected ion detection.

[0069] Selected ion chromatograms of each target carcinogenic polycyclic aromatic hydrocarbon were obtained in a GC / MS workstation. Qualitative and quantitative analysis of each polycyclic aromatic hydrocarbon in the naphthenic lubricating oil sample was performed, and the quantitative results are shown in Table 2.

[0070] Example 23: Weigh 0.2g of cycloalkyl lubricating oil sample, add 10ml of cyclohexane to dissolve evenly, add 10ml of dimethyl sulfoxide to extract the sample solution, shake vigorously for 2min, and let stand to separate the layers. Collect the upper extract, and repeat the extraction of the lower residual liquid with 10ml of dimethyl sulfoxide. Combine the extracts. Add 70ml of 4% sodium chloride solution to the dimethyl sulfoxide extract to reduce its solubility, then add 5ml of cyclohexane for back-extraction, shake vigorously for 2min, and let stand to separate the layers. Collect the upper extract, and extract the lower aqueous phase again with 5ml of cyclohexane. Combine the extracts. Wash the cyclohexane extract twice with 5ml of 70℃ hot sodium chloride solution, discard the aqueous layer, concentrate the cyclohexane extract using a rotary evaporator, and bring the volume to 1ml with cyclohexane for analysis.

[0071] 1 μl of dodecadeuterium perylene of known concentration was added as an internal standard, and the analyte solution was detected by GC / MS to obtain a selected ion chromatogram of the polycyclic aromatic hydrocarbons (PAHs). Chromatographic conditions: Nonpolar 60 m × 0.38 mm × 0.1 μm column; injection port temperature 280 °C; carrier gas: helium; splitless injection; temperature program: starting at 35 °C, ramping at 15 °C / min to 310 °C, and holding until all components elute. Mass spectrometry conditions: GC / MS interface temperature 280 °C; mass spectrum scan range 30 amu to 500 amu; electron impact ionization energy 70 eV; EI ion source temperature 280 °C; acquisition mode: selected ion detection.

[0072] Selected ion chromatograms of each target carcinogenic polycyclic aromatic hydrocarbon were obtained in a GC / MS workstation. Qualitative and quantitative analysis of each polycyclic aromatic hydrocarbon in the naphthenic lubricating oil sample was performed, and the quantitative results are shown in Table 2.

[0073] Comparative Example 1: The sample from Example 20 was tested using existing methods, and the results are explained in Table 2. The existing method refers to "SN / T 1877.3-2007 Determination of Polycyclic Aromatic Hydrocarbons in Mineral Oils," and the specific operation is as follows: Weigh 1-2 g of mineral oil sample into a beaker, add 5 mL of cyclohexane to dissolve, and transfer to a separatory funnel. Wash the beaker with about 5 mL of cyclohexane and transfer it to the same separatory funnel. Add 8 mL of dimethyl sulfoxide (DMSO), shake vigorously for about 1 min, and allow to stand for separation. Transfer the lower DMSO phase to another separatory funnel. Extract the residual liquid again with 8 mL of DMSO, combine the extracts, and discard the cyclohexane layer. Add 5 mL of cyclohexane and 80 mL of sodium chloride solution to the DMSO extract, shake vigorously for about 2 min, and allow to stand for separation. Place the lower aqueous phase in another separatory funnel, extract once again with 5 mL of cyclohexane, combine the extracts, and discard the aqueous phase. The extract was washed twice with 5 mL of sodium chloride solution heated to 70 °C using a water bath. The aqueous layer was discarded, and the cyclohexane layer was transferred to a stoppered quantitative test tube. The solution was concentrated to near dryness by nitrogen purging or other methods. Hexane was added to bring the volume to 1 mL, and an internal standard solution was added for GC / MS analysis.

[0074] Chromatographic conditions: Column: 30m × 0.25mm (inner diameter) × 0.10μm (film thickness) DB-5MS quartz capillary column or equivalent; Temperature program: 50℃ for 1 min, then ramp to 200℃ at 25℃ / min, then ramp to 315℃ at 8℃ / min, and hold until all components elute. Mass spectrometry conditions were the same as in Example 20.

[0075] Comparative Example 2: The sample of Example 21 was tested using existing methods. The results are explained in Table 2, where the existing methods are the same as those in Comparative Example 1.

[0076] Comparative Example 3: The sample of Example 22 was tested using existing methods. The results are explained in Table 2, where the existing methods are the same as those in Comparative Example 1.

[0077] Comparative Example 4: The sample of Example 23 was tested using existing methods. The results are explained in Table 2, where the existing methods are the same as those in Comparative Example 1.

[0078] Figure 1 and Figure 2 The total ion chromatograms of Example 20 and Comparative Example 1, respectively, are obtained from... Figure 1 and Figure 2 As can be seen from the comparison of data in Table 2, the sample weighing and gas chromatography-mass spectrometry conditions of existing methods are not suitable for the detection of carcinogenic polycyclic aromatic hydrocarbons in naphthenic lubricating oils, and the total ion chromatogram of naphthenic lubricating oils exhibits a "large peak package" state. Existing method conditions result in significant matrix interference, affecting the separation and integration calculation of target peaks. Under the method conditions of this invention, matrix interference is smaller, achieving effective separation of target compounds and improving quantitative accuracy. Simultaneously, this invention adds the investigation of carcinogenic polycyclic aromatic hydrocarbons benzo[e]pyrene and benzo[j]fluoranthene, meeting the industry's testing needs for naphthenic lubricating oil products.

[0079] In summary, this application provides a method for the qualitative and quantitative analysis of carcinogenic polycyclic aromatic hydrocarbons in naphthenic lubricating oils. The method uses gas chromatography-mass spectrometry (GC / MS) to separate and identify target polycyclic aromatic hydrocarbons, and uses internal standard method for quantification. This method can effectively reduce matrix interference during the separation of target compounds. The method is simple to operate, easy to implement, and has good repeatability and reproducibility.

[0080] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the needs of different situations.

Claims

1. A method for the analysis of carcinogenic polycyclic aromatic hydrocarbons in naphthenic base lubricating oils, characterized in that The method comprises the following steps: Preparation of a standard working solution of polycyclic aromatic hydrocarbons; Extraction of the naphthenic base lubricating oil with dimethyl sulfoxide and back extraction with cyclohexane to obtain a test solution; Separation and detection of the standard working solution of polycyclic aromatic hydrocarbons and the test solution by gas chromatography-mass spectrometry; Obtaining of a standard curve of polycyclic aromatic hydrocarbons according to the detection results of gas chromatography-mass spectrometry, and qualitative and quantitative determination of polycyclic aromatic hydrocarbons in the test solution in combination with the standard curve of polycyclic aromatic hydrocarbons.

2. The method of analyzing carcinogenic polycyclic aromatic hydrocarbons in naphthenic base lubricating oils according to claim 1, characterized in that The quantitative determination of the content of polycyclic aromatic hydrocarbons in the test solution is performed by an internal standard method, and the internal standard is one or more of dodecadeuterated perylene, benzo(a)anthracene deuterium twelve, benzo(b)fluoranthene deuterium twelve and benzo(a)pyrene deuterium twelve.

3. The method for analyzing carcinogenic polycyclic aromatic hydrocarbons in naphthenic lubricating oils according to claim 1 or 2, characterized in that The operation steps of extraction of the naphthenic base lubricating oil with dimethyl sulfoxide and back extraction with cyclohexane comprise: Step 1: taking a required amount of naphthenic base lubricating oil sample, adding cyclohexane for dissolution to obtain a sample solution; Step 2: adding dimethyl sulfoxide to the sample solution, and after extraction, obtaining a dimethyl sulfoxide extract solution; Step 3: adding sodium chloride solution and cyclohexane to the dimethyl sulfoxide extract solution for back extraction, and after washing of the extract solution, obtaining a test solution.

4. The method of analyzing carcinogenic polycyclic aromatic hydrocarbons in naphthenic base lubricating oils according to claim 3, characterized in that The number of extraction and back extraction is 2 to 4 times.

5. The method of analysis of naphthenic, carcinogenic polycyclic aromatic hydrocarbons in lubricating oils according to claim 3 or 4, characterized in that In Step 1, the sampling amount of the naphthenic base lubricating oil is 0.05 g to 1 g.

6. The method for the analysis of carcinogenic polycyclic aromatic hydrocarbons in naphthenic lubricating oils according to any one of claims 3 to 5, characterized in that In Step 2, the amount of dimethyl sulfoxide used for single extraction is 8 ml to 12 ml.

7. The method for the analysis of carcinogenic polycyclic aromatic hydrocarbons in naphthenic lubricating oils according to any one of claims 3 to 6, characterized in that In Step 3, the amount of cyclohexane used for single back extraction is 5 ml to 10 ml, the amount of sodium chloride solution is 60 ml to 90 ml, and the mass concentration of the sodium chloride solution is 4% to 6%.

8. The method for the analysis of carcinogenic polycyclic aromatic hydrocarbons in naphthenic lubricating oils according to any one of claims 3 to 7, characterized in that In Step 3, the washing of the extract solution comprises: adding 5 ml to 10 ml of sodium chloride solution with a temperature of 70℃ to the cyclohexane extract solution obtained by back extraction for washing twice.

9. The method for the analysis of naphthenic lube oil carcinogenic polycyclic aromatics according to any one of claims 1 to 8, characterized in that The chromatographic conditions for gas chromatography-mass spectrometry detection are as follows: the chromatographic column is a non-polar chromatographic column or a weakly polar chromatographic column, the column length is 30 m to 60 m, the diameter is 0.25 mm to 0.5 mm, the injection port temperature is 270℃ to 300℃, the injection is non-split, the carrier gas is helium, and the temperature program is: the initial temperature is 35℃ to 50℃, and then the temperature is raised to 310℃, and the temperature is kept until all components flow out, and the temperature rising speed is 5℃ / min to 15℃ / min.

10. The method for the analysis of carcinogenic polycyclic aromatic hydrocarbons in naphthenic lubricating oils according to any one of claims 1 to 9, characterized in that The mass spectrometry conditions for gas chromatography-mass spectrometry detection are as follows: the GC / MS interface temperature is 270℃ to 300℃, the mass spectrometry scanning range is 30 amu to 500 amu, the electron impact ionization energy is 70 eV to 90 eV, the EI ion source temperature is 260℃ to 300℃, and the determination mode is the selected ion detection mode.

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