Method for detecting oxygenate components in fischer-tropsch waxes

Abstract

The present application relates to the technical field of Fischer-Tropsch synthesis wax analysis chemistry, and in particular to a method for detecting oxygen-containing compound components in Fischer-Tropsch synthesis wax by using solid-phase microextraction and comprehensive two-dimensional gas chromatography-mass spectrometry. The method comprises the following steps: first, performing solid-phase microextraction on a to-be-tested wax sample to obtain an extract rich in oxygen-containing compound components; and then using comprehensive two-dimensional gas chromatography-mass spectrometry to qualitatively determine the composition of the oxygen-containing compound components contained in the extract. In the method, the content of the oxygen-containing compound components is less than or equal to 7 wt% based on the total weight of the Fischer-Tropsch synthesis wax. The method has the characteristics of high throughput, high sensitivity and high accuracy, and solves the problems of difficult analysis and separation and difficult qualitative determination of alcohol, aldehyde, ketone, acid, ester and other oxygen-containing compound components in Fischer-Tropsch synthesis wax.

Description

Technical Field

[0001] This invention relates to the field of analytical chemistry technology for Fischer-Tropsch synthetic waxes, specifically to a method for detecting oxygen-containing components in Fischer-Tropsch synthetic waxes using solid-phase microextraction and full two-dimensional gas chromatography-mass spectrometry. Background Technology

[0002] Fischer-Tropsch synthetic wax is one of the main products of the Fischer-Tropsch synthesis reaction and an important raw material for hydrorefining. It can be processed into product wax through physical processes or produced into high-quality diesel oil and lubricating oil base oil through hydrocracking / isomerization. It has a wide range of industrial applications, including polishing agents, cardboard coatings, hot melt adhesives, printing ink ingredients, insulation, lubricants, and wax products in the cable and electronics industries. It is a chemical product with high economic value.

[0003] Fischer-Tropsch synthetic waxes are methylene polymers, primarily composed of alkanes, with trace amounts of alkenes, alcohols, aldehydes, ketones, acids, and esters. Their compositional analysis is a crucial indicator for wax product processing and utilization. This indicator reflects the distribution of Fischer-Tropsch synthesis reaction products and the performance of the Fischer-Tropsch catalyst. It also provides important guidance for the further conversion of Fischer-Tropsch synthetic waxes into diesel, naphtha, and high-quality lubricating oil base oils. Therefore, detailed component analysis of Fischer-Tropsch synthetic waxes is of significant guiding importance for production and user applications, and will play a positive role in producing high-quality oil products, addressing my country's energy crisis, and building a resource-saving and environmentally friendly society.

[0004] Because the carbon number composition of Fischer-Tropsch synthetic waxes ranges from C5 to C6. 100 The boiling points of Fischer-Tropsch waxes can reach over 720°C, which significantly limits their compositional analysis. Current research primarily focuses on carbon number distribution, with very little detailed analysis of their components. Existing literature on carbon number distribution determination, such as supercritical fluid chromatography and gel permeation chromatography, is cumbersome, costly, and insufficient for the required compositional analysis of Fischer-Tropsch waxes. Therefore, more advanced and effective methods are needed for in-depth understanding and detailed research into the composition of Fischer-Tropsch waxes, providing data support for researchers' further exploration of downstream product conversion.

[0005] The separation and identification of Fischer-Tropsch synthetic waxes by high-temperature gas chromatography and high-temperature gas chromatography-mass spectrometry (Chromatography, 2018, 36(3), 303-308) proposed the use of special chromatographic conditions and columns to separate Fischer-Tropsch synthetic waxes. This method has a good separation effect on n-alkanes and some unknown components in Fischer-Tropsch waxes. However, due to the high boiling point of Fischer-Tropsch waxes, they are not suitable for component identification by mass spectrometry. Only by pretreatment to distill and obtain Fischer-Tropsch fraction waxes can the Fischer-Tropsch fraction waxes be identified by mass spectrometry analysis, in addition to n-alkanes, as some alkanes, alkenes and oxygen-containing compounds.

[0006] Determination of n-alkanes in crude liquid wax from coal-based Fischer-Tropsch synthesis (《Detection and Testing》2019, 5, 157-159). A gas chromatography method for determining the n-alkanes in crude liquid wax from coal-based Fischer-Tropsch synthesis is proposed. However, this method has a relatively narrow range of carbon numbers for the Fischer-Tropsch synthesis wax (up to C14). 17 ), while the carbon number range of Fischer-Tropsch waxes can reach C. 80 Even higher levels of Fischer-Tropsch wax make it difficult to determine the content of n-alkanes, and the determination of trace components is also challenging.

[0007] In summary, current methods for determining Fischer-Tropsch synthetic wax components mainly involve qualitative and quantitative analysis of n-alkanes or analysis of a certain light component of Fischer-Tropsch liquid wax. Moreover, current methods are limited by the high boiling point of Fischer-Tropsch synthetic waxes, making it difficult to achieve complete separation on a chromatographic column and thus difficult to perform detailed qualitative and quantitative analysis of Fischer-Tropsch synthetic wax components. Summary of the Invention

[0008] The purpose of this invention is to overcome the technical problem that the analysis of oxygen-containing components in Fischer-Tropsch synthetic waxes is limited by the high boiling point of Fischer-Tropsch waxes, and to provide a method for detecting oxygen-containing components in Fischer-Tropsch synthetic waxes using solid-phase microextraction and full two-dimensional gas chromatography-mass spectrometry. This method enables qualitative and quantitative analysis of oxygen-containing components (alcohols, aldehydes, ketones, acids, esters, etc.) in Fischer-Tropsch synthetic waxes.

[0009] To achieve the above objectives, the present invention provides a method for detecting oxygen-containing components in Fischer-Tropsch synthetic waxes. The method includes: firstly performing solid-phase microextraction on the wax sample to be tested to obtain an extract enriched with oxygen-containing components, and then qualitatively determining the composition of the oxygen-containing components contained in the extract using two-dimensional gas chromatography-mass spectrometry.

[0010] Based on the total weight of the Fischer-Tropsch synthetic wax, the content of the oxygen-containing compound component is ≤7 wt%.

[0011] Preferably, the method includes the following steps:

[0012] (1) Solid-phase microextraction: Weigh 0.1-0.5g of the wax sample to be tested into a 20mL headspace vial, add internal standard, and tighten the headspace vial cap; then preheat at 80-110℃ for 30-40min, insert the extraction head into the headspace vial, and extract at 80-110℃ for 20-50min; the insertion depth of the extraction head in the headspace vial is 1-1.5cm;

[0013] (2) Two-dimensional gas chromatography-mass spectrometry analysis: After solid phase microextraction, the extraction head is inserted into the injection port of the two-dimensional gas chromatography-mass spectrometer, and thermally desorbed at 250-280℃ for 5-10 min, followed by analysis by two-dimensional gas chromatography-mass spectrometry.

[0014] (3) The composition of the oxygen-containing compound components was qualitatively determined by combining the retention time index and the NIST spectral library.

[0015] Compared with the prior art, the present invention has the following advantages:

[0016] (1) The method provided by the present invention first uses solid phase microextraction technology to extract oxygen-containing compound components (e.g., alcohols, aldehydes, ketones, acids and esters) in the Fischer-Tropsch synthetic wax to obtain an extract enriched with oxygen-containing compound components; then, the oxygen-containing compound components contained in the extract are orthogonally separated by two chromatographic columns with different polarities, and the detection is completed by mass spectrometry under the action of a modulator; at the same time, the method has the characteristics of simple processing, fast analysis speed, economic practicality, convenient operation, and green environmental protection.

[0017] (2) The present invention uses solid phase microextraction to overcome the defects of traditional sample pretreatment technology. It integrates sampling, extraction, concentration and injection, which greatly speeds up the analysis and detection. The analytical equipment used to determine oxygen-containing compound components has the characteristics of high throughput, high sensitivity and high accuracy. Compared with the traditional gas chromatography-mass spectrometry, it has the advantages of larger peak capacity, higher resolution, better sensitivity and more regular qualitative analysis. Attached Figure Description

[0018] Figure 1 This is a chromatogram of the oxygen-containing compound components in the wax sample to be tested, obtained using conventional methods.

[0019] Figure 2 It is a one-dimensional projection of the full two-dimensional gas chromatography-mass spectrometry of the oxygen-containing compound components in the wax sample to be tested;

[0020] Figure 3 It is a two-dimensional surface map of oxygen-containing compound components in the wax sample to be tested using full two-dimensional gas chromatography-mass spectrometry.

[0021] Figure 4 This is a schematic diagram of the three-dimensional profile of the oxygen-containing compound components in the wax sample to be tested using a full two-dimensional gas chromatography-mass spectrometry. Detailed Implementation

[0022] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0023] This invention provides a method for detecting oxygen-containing compound components in Fischer-Tropsch synthetic waxes. The method includes: firstly performing solid-phase microextraction on the wax sample to be tested to obtain an extract enriched with oxygen-containing compound components, and then qualitatively determining the composition of the oxygen-containing compound components contained in the extract using two-dimensional gas chromatography-mass spectrometry.

[0024] Specifically, based on the total weight of the Fischer-Tropsch synthetic wax, the content of the oxygen-containing compound component in the Fischer-Tropsch synthetic wax is ≤7wt%.

[0025] The inventors of this invention discovered that the uniquely high boiling point of Fischer-Tropsch synthetic waxes makes compositional analysis using gas chromatography extremely difficult. On one hand, the high boiling point of Fischer-Tropsch synthetic waxes leaves significant residue on the chromatographic column, affecting separation efficiency and reducing column lifespan. On the other hand, advancements in chromatographic technology limit the use of longer-lasting and higher-temperature-resistant columns for Fischer-Tropsch synthetic waxes. Therefore, solid-phase microextraction (SPE) is employed to extract and enrich the main oxygen-containing compounds in Fischer-Tropsch synthetic waxes, selectively performing two-dimensional gas chromatography-mass spectrometry (GC-MS) analysis on the analytes. This solves the long-standing problem of the difficulty in using mass spectrometry to analyze the high boiling point of Fischer-Tropsch synthetic waxes. Furthermore, compared to traditional GC-MS, the two-dimensional GC-MS method used in this invention offers advantages such as high throughput, high sensitivity, high accuracy, large peak capacity, and high resolution.

[0026] In this invention, solid-phase microextraction (SPME) technology is based on using fused silica fibers coated with a stationary phase to adsorb and enrich the analytes in the sample. Its greatest advantage is that it can concentrate the analyte while extracting. SPME overcomes the shortcomings of traditional sample pretreatment techniques, integrating sampling, extraction, concentration, and injection into one process, greatly accelerating the speed of analysis and detection.

[0027] In this invention, a two-dimensional gas chromatography-mass spectrometry (GC×GC-MS) system connects two column systems in series. With the aid of a modulator, orthogonal separation of complex samples is achieved. Compounds with similar polarities that cannot be separated on a one-dimensional column can be further separated on a two-dimensional column based on their boiling point differences, significantly improving the peak capacity of the chromatogram. Separating oxygen-containing components in Fischer-Tropsch waxes in two dimensions based on their boiling point and polarity differences greatly avoids the drawbacks of co-current compounds with similar boiling points in conventional chromatographic analysis, achieving precise separation and accurate qualitative analysis of oxygen-containing components in Fischer-Tropsch waxes.

[0028] In some embodiments of the present invention, preferably, the content of the oxygen-containing compound component in the Fischer-Tropsch synthetic wax is 0.01-7 wt%, based on the total weight of the Fischer-Tropsch synthetic wax.

[0029] In some embodiments of the present invention, preferably, the oxygen-containing compound component in the Fischer-Tropsch synthetic wax is selected from at least one of alcohols, aldehydes, ketones, acids, and esters.

[0030] In some embodiments of the present invention, preferably, based on the total weight of the Fischer-Tropsch synthetic wax, the content of each of the alcohols, aldehydes, ketones, acids and esters in the Fischer-Tropsch synthetic wax is ≤1 wt%, preferably 0.01-1 wt%.

[0031] According to the present invention, preferably, the method includes the following steps:

[0032] (1) Solid-phase microextraction: Weigh 0.1-0.5g of the wax sample to be tested into a 20mL headspace vial, add internal standard, and tighten the headspace vial cap; then preheat at 80-110℃ for 30-40min, insert the extraction head into the headspace vial, and extract at 80-110℃ for 20-50min; the insertion depth of the extraction head in the headspace vial is 1-1.5cm;

[0033] (2) Two-dimensional gas chromatography-mass spectrometry analysis: After solid phase microextraction, the extraction head is inserted into the injection port of the two-dimensional gas chromatography-mass spectrometer, and thermally desorbed at 250-280℃ for 5-10 min, followed by analysis by two-dimensional gas chromatography-mass spectrometry.

[0034] (3) The composition of the oxygen-containing compound components was qualitatively determined by combining the retention time index and the NIST spectral library.

[0035] In some embodiments of the present invention, preferably, the internal standard is a methanol solution containing 3-methyl-1-pentanol, 3-methyl-2-hexanone, 3-methylhexanoic acid, and ethyl formate; more preferably, in the methanol solution, the concentrations of 3-methyl-1-pentanol, 3-methyl-2-hexanone, 3-methylhexanoic acid, and ethyl formate are each independently 0.01-0.5 wt%, for example, 0.01 wt%, 0.05 wt%, 0.1 wt%, 0.15 wt%, 0.2 wt%, 0.5 wt%, and any value within a range of any two values, preferably 0.05-0.2 wt%.

[0036] In this invention, unless otherwise specified, 3-methyl-1-pentanol is used as an internal standard for alcohols; 3-methyl-2-hexanone is used as an internal standard for aldehydes and ketones; 3-methylhexanoic acid is used as an internal standard for acids; and ethyl formate is used as an internal standard for esters.

[0037] In a preferred embodiment of the present invention, the internal standard is 5 μL of a methanol solution containing 0.1 wt% 3-methyl-1-pentanol, 0.1 wt% 3-methyl-2-hexanone, 0.1 wt% 3-methylhexanoic acid and 0.1 wt% ethyl formate.

[0038] In some embodiments of the present invention, preferably, in step (1), the extraction temperature is 80-110℃, more preferably 95-105℃, and even more preferably 100℃. In the present invention, the extraction temperature is one of the important factors determining the solid-phase microextraction effect. A suitable extraction temperature can adsorb the analyte as much as possible, so that the equilibrium constants of the interfering matrix and the analyte at the extraction head are different.

[0039] In a preferred embodiment of the present invention, when the weight of the wax sample to be tested is 0.1g, the extraction temperature is 100℃, and the extraction time is 30min, the analysis by two-dimensional chromatography-mass spectrometry shows that the number of chromatographic peaks and the peak area are the largest, indicating that the extraction effect of the wax sample to be tested is the best under these conditions.

[0040] In this invention, the extraction head in solid-phase microextraction (SPE) has the characteristics of low adsorption of hydrocarbon matrix and high adsorption of oxygen-containing compound components. Preferably, the extraction head is a 70-90 μm fiber extraction head; more preferably, the fiber extraction head is a three-phase (DVB-PDMS-CAR) extraction head.

[0041] According to the present invention, preferably, the analytical conditions for full two-dimensional gas chromatography are as follows:

[0042] The chromatographic column system adopted was GC×GC column system, the one-dimensional column was HP-Innowax type chromatographic column with a diameter of 30 mm × 0.25 mm × 0.25 μm, the two-dimensional column was DB-17MS type secondary chromatographic column with a diameter of 0.9 m × 0.18 mm × 0.18 μm, and the modulation column was HV type with a diameter of 1.1 m.

[0043] Chromatographic conditions: Injector temperature 250-280℃; split mode, split ratio 30-50:1;

[0044] Column oven heating program: The initial temperature of the one-dimensional column and the two-dimensional column are 40-50℃ each independently, held for 8-10 min, and then heated to 260-280℃ at a heating rate of 3-5℃ / min, held for 5-10 min, with a modulator modulation time of 6-10 s and a release time of 5-9 s.

[0045] The inlet temperature program of the modulation column is as follows: the initial temperature is 105-115℃, hold for 2-3 min, and then increase the temperature to 300-320℃ at a rate of 3-5℃ / min, and hold for 8-10 min.

[0046] The cold trap heating program for the modulation column is as follows: the initial temperature is 8-9℃, held for 0-1 min, then cooled to -51℃ to 45℃ at a cooling rate of -50℃ / min to 40℃ / min, held for 20.8-22.8 min, and then heated to 8-10℃ at a heating rate of 20-25℃ / min, held for 20-40 min.

[0047] The outlet temperature rise program of the modulation column is as follows: the initial temperature is 165-175℃, hold for 2-5 min, then rise to 300-320℃ at a heating rate of 3-5℃ / min, and hold for 20-22 min.

[0048] Carrier gas: He, flow rate 1-1.5 mL / min.

[0049] In this invention, when using solid-phase microextraction (SPE) to detect low levels of oxygen-containing compounds in the wax sample, interference from matrix hydrocarbons is significant. Alkanes and alkenes are easily adsorbed by the SPE head, resulting in hundreds of interfering components. Furthermore, high levels of these interfering components can easily mask the determination of low-level components during chromatographic separation. Therefore, the selection of a one-dimensional column (30 mm × 0.25 mm × 0.25 μm HP-Innowax column) and a two-dimensional column (0.9 m × 0.18 mm × 0.18 μm DB-17MS secondary column) satisfies the separation requirements of the wax sample components while also saving costs.

[0050] According to the present invention, preferably, the analysis conditions for mass spectrometry are as follows: electron impact ion source, voltage of 70 eV, ion source temperature of 220-240°C, transfer line temperature of 270-290°C, mass number range of 40-400 amu, and solvent delay of 4-4.5 min.

[0051] In this invention, the mass spectrometry data acquired by this method is processed by the Canvas workstation data processing system. After automatically identifying chromatographic peaks with a signal-to-noise ratio greater than 100, automatic integration and mass spectrum library comparison are performed. The mass spectrum library is NIST2014. All comparison results are automatically generated into a peak table. The peak table is then further verified by manual spectral interpretation and comparison of the peak elution patterns of homologous compounds in two-dimensional chromatography as the preliminary identification result. Compounds with a similarity greater than 800 and a reverse similarity greater than 800 are selected as the final identification result.

[0052] The present invention will be described in detail below through embodiments.

[0053] Instruments: Agilent 7890A-5975C gas chromatograph-mass spectrometer, equipped with Snowscape SSM1810 solid-state thermal modulator, solid-phase microextraction microneedles and sleeves, electric heating plate, and analytical balance;

[0054] Reagents: 3-Methyl-1-pentanol, analytical grade; 3-methyl-2-hexanone, analytical grade; 3-methylhexanoic acid, analytical grade; ethyl formate, analytical grade; methanol, analytical grade.

[0055] Example

[0056] (1) Solid-phase microextraction: Weigh 0.1 g of the wax sample to be tested into a 20 mL headspace vial, and add 5 μL of methanol solution containing 0.1 wt% 3-methyl-1-pentanol, 0.1 wt% 3-methyl-2-hexanone, 0.1 wt% 3-methylhexanoic acid and 0.1 wt% ethyl formate as internal standard. Tighten the screw cap to seal. Heat the vial to 100 °C on a heating plate for 30 min. Insert the 80 μm three-phase (DVB-PDMS-CAR) extraction head of the solid-phase microextraction device into the sample vial to a depth of 1 cm. Extract at 100 °C for 30 min.

[0057] (2) Full two-dimensional gas chromatography-mass spectrometry analysis: After solid phase microextraction, the extraction head is placed in the GC injection port, thermally desorbed at 260℃ for 5 min, and then waited for GCXGC-MS analysis and detection.

[0058] Analytical conditions for two-dimensional gas chromatography:

[0059] The chromatographic column system adopted was GC×GC column system. The one-dimensional column was HP-Innowax type column, 30m×0.25mm (inner diameter)×0.25μm (film thickness); the two-dimensional column was DB-17MS type secondary chromatographic column, 0.9m×0.18mm (inner diameter)×0.18μm (film thickness); the modulation column was HV type (C5-C30), 1.1m.

[0060] Chromatographic conditions: Injector temperature 260℃, split injection mode, split ratio 30:1;

[0061] The column oven heating program for one-dimensional and two-dimensional columns is as follows: the initial temperature is 40℃, and after holding for 10 minutes, the temperature is increased to 250℃ at a rate of 5℃ / min, and held for 5 minutes. The modulation time of the modulator is 6 seconds, and the release time is 5 seconds.

[0062] The inlet temperature program of the modulation column is as follows: the initial temperature is 110℃, held for 2 min, and then increased to 320℃ at a rate of 5℃ / min, held for 10 min.

[0063] The cold trap heating program for the modulation column is as follows: the initial temperature is 9℃, held for 0 min, then cooled to -51℃ at -50℃ / min, held for 20.8 min, and then heated to 9℃ at 20℃ / min, held for 29 min.

[0064] The outlet temperature program of the modulation column is as follows: the initial temperature is 170℃, held for 2 min, and then increased to 320℃ at a rate of 5℃ / min, held for 22 min.

[0065] The sample was run in constant flow mode, with high-purity helium gas (>99.999% by volume) as the carrier gas and a flow rate of 1 mL / min.

[0066] The analytical conditions for mass spectrometry are:

[0067] The electron impact ion source operates at a voltage of 70 eV, an ion source temperature of 230°C, a transmission line temperature of 280°C, and a sampled mass number range of 40-400 amu.

[0068] (3) Data acquisition was controlled by the Canvas instrument workstation software. The test results of the composition of oxygen-containing compounds in the wax sample to be tested are shown in Table 1.

[0069] The chromatogram of the oxygen-containing components in the wax sample analyzed using a conventional method (i.e., one-dimensional high-temperature gas chromatography, employing a 10m non-polar column, initial temperature 50℃, heating at 9℃ / min to 430℃, and holding for 15min) is shown below. Figure 1 As shown, by Figure 1 It is known that, due to the high boiling point of Fischer-Tropsch synthetic waxes, it is difficult to separate n-alkanes from other alkenes, isoalkanes, and oxygen-containing compounds in Fischer-Tropsch synthetic waxes.

[0070] The one-dimensional projection of the full two-dimensional gas chromatography-mass spectrometry of oxygen-containing compounds in the wax sample is shown below. Figure 2 As shown, by Figure 2 It can be seen that there are obvious other chromatographic peaks between every two large chromatographic peaks (e.g., n-alkanes).

[0071] Two-dimensional surface patterns of oxygen-containing compound components in the wax sample are shown in the full two-dimensional gas chromatography-mass spectrometry (GC-MS) image. Figure 3 As shown, by Figure 3 It can be seen that the composition and distribution of oxygen-containing compounds in the wax sample to be tested can be clearly observed.

[0072] A schematic diagram of the three-dimensional profile of the oxygen-containing compound components in the wax sample under full two-dimensional gas chromatography-mass spectrometry is shown below. Figure 4 As shown, by Figure 4 It can be seen that the distribution of oxygen-containing compounds in the wax sample to be tested can be observed more intuitively.

[0073] Table 1

[0074]

[0075]

[0076]

[0077]

[0078]

[0079]

[0080] As shown in Table 1, the collected mass spectrometry data were processed by the Canvas workstation data processing system. After automatically identifying chromatographic peaks with a signal-to-noise ratio greater than 100, automatic integration and mass spectrum library comparison were performed. The mass spectrum library was NIST2014. All comparison results were automatically generated into a peak table. The peak table was further verified by manual spectral interpretation and comparison with the peak elution patterns of homologues in two-dimensional chromatography, and then used as the preliminary identification results. Using the method of this invention, a total of 280 components of trace oxygen-containing compounds were detected in Fischer-Tropsch synthetic wax. Compounds with a similarity greater than 800 and a reverse similarity greater than 800 were selected as the final identification results, totaling 132 components.

[0081] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for detecting oxygen-containing compound components in Fischer-Tropsch synthetic waxes, characterized in that, The method includes: first, performing solid-phase microextraction on the wax sample to be tested to obtain an extract enriched with oxygen-containing compounds; then, using full two-dimensional gas chromatography-mass spectrometry to qualitatively determine the composition of the oxygen-containing compounds contained in the extract. Specifically, based on the total weight of the Fischer-Tropsch synthetic wax, the content of the oxygen-containing compound component in the Fischer-Tropsch synthetic wax is 0.01-7 wt%; based on the total weight of the Fischer-Tropsch synthetic wax, the content of alcohols, aldehydes, ketones, acids, and esters in the Fischer-Tropsch synthetic wax is independently 0.01-1 wt%. The method includes the following steps: (1) Solid-phase microextraction: Weigh 0.1g of the wax sample to be tested and place it in a 20mL headspace vial, add internal standard, and tighten the headspace vial cap; then preheat at 100℃ for 30min, insert the extraction head into the headspace vial, and extract at 100℃ for 30min; the insertion depth of the extraction head in the headspace vial is 1cm; (2) Two-dimensional gas chromatography-mass spectrometry analysis: After solid-phase microextraction, insert the extraction head into the injection port of two-dimensional gas chromatography-mass spectrometry, thermally desorb at 250-280℃ for 5-10min, and analyze by two-dimensional gas chromatography-mass spectrometry; (3) Use retention time index and NIST spectral library to qualitatively characterize the composition of the oxygen-containing compound components; the extraction head is an 80µm three-phase DVB-PDMS-CAR extraction head; The internal standard is a 5 μL methanol solution containing 3-methyl-1-pentanol, 3-methyl-2-hexanone, 3-methylhexanoic acid, and ethyl formate, wherein the concentrations of each of the methanol solutions are independently 0.1 wt%. Among them, the full two-dimensional gas chromatography meets the following requirements: the chromatographic column adopts a GC×GC column system, the one-dimensional column is a 30mm×0.25mm×0.25µm HP-Innowax type chromatographic column, the two-dimensional column is a 0.9m×0.18mm×0.18µm DB-17 MS type secondary chromatographic column, and the modulation column is a 1.1m HV type; The analytical conditions for full two-dimensional gas chromatography are as follows: Chromatographic conditions: Injector temperature 260℃, split injection mode, split ratio 30:1; The column oven heating program for one-dimensional and two-dimensional columns is as follows: the initial temperature is 40℃, and after holding for 10 minutes, the temperature is increased to 250℃ at a rate of 5℃ / min, and held for 5 minutes. The modulation time of the modulator is 6 seconds, and the release time is 5 seconds. The inlet temperature program of the modulation column is as follows: the initial temperature is 110℃, held for 2 min, and then increased to 320℃ at a rate of 5℃ / min, held for 10 min. The cold trap heating program for the modulation column is as follows: the initial temperature is 9℃, held for 0 min, then cooled to -51℃ at -50℃ / min, held for 20.8 min, and then heated to 9℃ at 20℃ / min, held for 29 min. The outlet temperature program of the modulation column is as follows: the initial temperature is 170℃, held for 2 min, and then increased to 320℃ at a rate of 5℃ / min, held for 22 min. The sample was run in constant flow mode, with high-purity helium gas (>99.999% by volume) as the carrier gas and a flow rate of 1 mL / min. Among them, the analytical conditions for mass spectrometry are: Electron impact ion source with voltage of 70 eV, ion source temperature of 220-240℃, transmission line temperature of 270-290℃, acquisition mass number range of 40-400 amu, and solvent delay of 4-4.5 min.

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