Method for analyzing target compounds in a marine fuel and use thereof

Abstract

This invention relates to the field of chemical analysis technology, and more particularly to an analytical method for target compounds in marine fuels and its application. The invention discloses an analytical method for target compounds in marine fuels, comprising the following steps: S100, Sample preparation: diluting a marine fuel or biofuel sample with an organic solvent to obtain a sample to be tested; S200, Derivatization: adding a derivatization reagent to the sample to be tested to perform a derivatization reaction, obtaining a derivatized sample; S300, GC-MS analysis: analyzing the derivatized sample using GC-MS to obtain the concentration of the target compound in the sample to be tested. This analytical method for target compounds in marine fuels, and its application, enables the simultaneous detection of multiple target compounds with different properties through unified sample preparation, derivatization treatment, and gas chromatography-mass spectrometry (GC-MS) analysis steps.

Description

Technical Field

[0001] This invention relates to the field of chemical analysis technology, and in particular to an analytical method for a target compound in marine fuel and its application. Background Technology

[0002] Marine fuels, including traditional distillate fuels, residue fuels, and emerging biofuels, have highly complex chemical compositions. These components include environmental pollutants requiring monitoring (such as 1,2-dichloroethane, styrene, and phenolic compounds), key components affecting fuel combustion performance and stability (such as fatty acids and glycerides), and biomarkers used to determine the origin of biofuels (such as ginkgolic acid and ginkgol). Therefore, developing analytical methods capable of accurately detecting these target compounds is crucial for fuel quality control, environmental safety assessments, and trade compliance reviews.

[0003] However, these target compounds exhibit vastly different physicochemical properties. For example, 1,2-dichloroethane and tetrachloroethylene are low-boiling, volatile halogenated hydrocarbons; phenols and cresols are highly polar, resulting in poor peak shapes when directly analyzed by gas chromatography; while palmitic acid, oleic acid, stearic acid, glycerides, and rosin acid are high-boiling, highly polar compounds that easily decompose at high temperatures and are difficult to vaporize directly. In existing technologies, multiple completely different analytical schemes are typically required for these compounds with such diverse properties. For instance, headspace sampling-gas chromatography is commonly used for volatile organic compounds; derivatization is required for phenols before analysis; and high-boiling fatty acids and glycerides often require liquid chromatography or more complex sample pretreatment procedures. This fragmented analytical approach, using one method for each class of compounds, leads to long detection cycles, cumbersome operations, high costs, and makes it difficult to obtain comprehensive chemical information from a single sample.

[0004] Therefore, developing a unified analytical method capable of simultaneously processing and detecting multiple target compounds with different boiling points and polarities in marine fuels has become a pressing technical problem to be solved in this field. Summary of the Invention

[0005] This invention addresses the shortcomings of existing technologies by providing an analytical method for target compounds in marine fuels and its application. This method, through standardized sample preparation, derivatization, and gas chromatography-mass spectrometry (GC-MS) analysis steps, enables the simultaneous detection of multiple target compounds with different properties.

[0006] Therefore, the first objective of this invention is to provide a method for analyzing target compounds in marine fuels.

[0007] A second objective of this invention is to provide an application of a method for analyzing target compounds in marine fuels.

[0008] To achieve the first objective of this invention, the technical solution of this invention provides an analytical method for a target compound in marine fuel, comprising the following steps: S100, sample preparation: diluting a marine fuel or biofuel sample with an organic solvent to obtain a sample to be tested; S200, derivatization: adding a derivatization reagent to the sample to be tested to carry out a derivatization reaction to obtain a derivatized sample; S300, GC-MS analysis: placing the derivatized sample in a GC-MS for analysis to obtain the concentration of the target compound in the sample to be tested.

[0009] Compared with existing technologies, the technical advantages of this approach are as follows: By unifying the dilution and derivatization pretreatment process, various target compounds that previously required multiple different methods to detect are integrated into a single analytical workflow, significantly simplifying the operation steps and reducing detection costs and time. Simultaneously, the derivatization process transforms highly polar compounds such as carboxylic acids, phenols, alcohols, and glycerides, which are difficult to directly vaporize, into derivatives suitable for GC-MS analysis. This enables the simultaneous detection of multiple compounds with different properties, overcoming the shortcomings of existing technologies that require different analytical methods for different compounds.

[0010] In one embodiment of the present invention, the target compound comprises at least one of the following: glyceryl palmitate, 4-hexylresorcinol, phenol, o-methylphenol, 4-cinnamonol, 2-ethylphenol, stearic acid, acetophenone, m-methylphenol, 5-pentylresorcinol, 4-methyl-1,2-benzenehydrin, palmitic acid, 1-tetradecyl alcohol, 2-ethylhexanoic acid, ginkgolic acid, 1-pentadecanol, bisphenol A, bisphenol F, 3,5-dihydroxytoluene, styrene, indene, polycyclopentadiene, glyceryl monostearate, oleic acid, 1,4-benzenehydrin, 4-ethylresorcinol, glycerol, 2,4-dimethylphenol, 4-tert-butyl-1,2-benzenehydrin, 1,2-dichloroethane, ginkgol, tetrachloroethylene, linoleic acid, p-methylphenol, 1,2-benzenehydrin, hexadecyl alcohol, rosin acid, and glyceryl monooleate.

[0011] Compared with existing technologies, the technical effects achieved by adopting this technical solution are as follows: It clarifies the scope of target substances applicable to this method, covering common volatile organic pollutants, phenolic compounds, fatty acids and their esters, glycerides, resin acids, bisphenol additives, and characteristic markers of biofuels in marine fuels. It provides a comprehensive range of detection targets for fuel quality control and environmental safety assessment, and has strong pertinence and practicality.

[0012] In one technical solution of the present invention, in step S100, the organic solvent is toluene; the concentration of the sample to be tested is 1 mg / L-10 mg / L.

[0013] Compared with existing technologies, the technical effects achieved by this solution are as follows: Toluene, as a solvent, can fully dissolve various non-polar and weakly polar components in marine fuel, ensuring sample homogeneity; limiting the sample concentration to the range of 1 mg / L to 10 mg / L matches the linear range of the subsequent calibration curve, ensuring the accuracy of quantitative analysis, while avoiding column overload or mass spectrometry detector saturation due to excessively high concentrations, and also avoiding undetectable signals due to excessively low concentrations, thus achieving a good balance between detection sensitivity and instrument protection.

[0014] In one technical solution of the present invention, in step S200, the derivatizing reagent is an N,O-bis(trimethylsilyl)trifluoroacetamide solution containing trimethylchlorosilane, wherein the content of trimethylchlorosilane is 1%.

[0015] Compared with existing technologies, the technical effects achieved by this solution are as follows: N,O-bis(trimethylsilyl)trifluoroacetamide is a highly efficient silanizing agent that can react with active hydrogens such as carboxyl, hydroxyl, and phenolic hydroxyl groups to generate trimethylsilyl ethers or trimethylsilyl ester derivatives, significantly improving the volatility and thermal stability of the target compound; 1% trimethylchlorosilane acts as a catalyst to accelerate the reaction process, shorten the derivatization time, and avoid over-derivatization or side reactions, ensuring the singleness of the derivatized product and the repeatability of quantitative analysis.

[0016] In one technical solution of the present invention, in step S200, the temperature of the derivatization reaction is 75℃-85℃; the time of the derivatization reaction is 50min-70min.

[0017] Preferably, in step S200, the temperature of the derivatization reaction is 80°C and the time of the derivatization reaction is 60 min.

[0018] Compared with existing technologies, the technical effects achieved by this technical solution are as follows: within this temperature and time range, the derivatization reaction can proceed fully, especially for compounds with large steric hindrance such as glycerides and rosin acids, which can also achieve a high conversion rate; at the same time, it avoids the decomposition of derivatives or the generation of by-products that may be caused by excessively high temperature or excessively long time.

[0019] In one technical solution of the present invention, GC analysis uses at least one of a first chromatographic column and a second chromatographic column, wherein the first chromatographic column is a DB-5MS chromatographic column and the second chromatographic column is a DB-624UI chromatographic column.

[0020] Compared with existing technologies, the technical advantages achieved by this solution are as follows: The DB-5MS column, using 5% phenyl-95% dimethylpolysiloxane as the stationary phase, exhibits excellent separation capability and thermal stability for high-boiling-point, weakly polar compounds; the DB-624UI column, using 6% cyanopropylphenyl-94% dimethylpolysiloxane as the stationary phase, provides better separation selectivity for low-to-medium boiling-point, moderately polar volatile organic compounds and phenolic compounds. Users can flexibly select a single column based on the boiling point range of the target compound, or inject two columns separately to obtain the most comprehensive information, demonstrating the flexibility and adaptability of the method.

[0021] In one technical solution of the present invention, the target compounds, from high to low boiling points, include: a first boiling point compound and a second boiling point compound, wherein the boiling point of the first boiling point compound is below 150°C and the boiling point of the second boiling point compound is above 150°C; wherein the first boiling point compound is analyzed using a second chromatographic column and the second boiling point compound is analyzed using a first chromatographic column.

[0022] Compared with existing technologies, the technical advantages of this solution are as follows: By rationally classifying target compounds using boiling point as a key physical property parameter, a scientific basis is provided for subsequent selection of suitable chromatographic columns and temperature programs. Using 150℃ as a cutoff point effectively distinguishes low-boiling-point volatile organic compounds from medium- and high-boiling-point compounds, allowing different categories of compounds to be analyzed under their respective optimal chromatographic conditions, thereby improving resolution and detection sensitivity. Due to the non-polarity and high-temperature resistance of its stationary phase, the DB-5MS column exhibits excellent separation capabilities for various compounds with boiling points above 150℃, including fatty acids, glycerides, rosin acids, bisphenols, and some high-boiling-point phenols and alcohols. Unifying the analysis of compounds in two boiling point ranges using the DB-5MS column simplifies the analytical process; a single injection provides complete information on medium- and high-boiling-point compounds, improving analytical efficiency.

[0023] In one technical solution of the present invention, the temperature program of the first chromatographic column is as follows: the initial temperature of the column oven is 60°C, the holding time is 2 min; the heating rate is 8°C / min; the final temperature of the column oven is 320°C, and the holding time is 6 min.

[0024] Compared with existing technologies, the technical effects achieved by this solution are as follows: the initial 60℃ ensures the preliminary separation of low-boiling-point solvents and light components after injection; the 2-minute holding time allows the solvent peaks to pass through fully without interfering with the target analyte; the relatively gentle heating rate of 8℃ / min enables good separation of components with broad boiling point distributions and avoids peak overlap; the final temperature of 320℃ ensures that high-boiling-point glycerides, rosin acids, etc., can be completely eluted without remaining in the chromatographic column; and the 6-minute holding time ensures that the peaks of the last eluted components are sharp and symmetrical, thereby guaranteeing the accuracy of quantitative analysis.

[0025] In one technical solution of the present invention, the temperature program of the second chromatographic column is as follows: the initial temperature of the column oven is 60°C, the holding time is 3 min; the heating rate is 15°C / min; the final temperature of the column oven is 245°C, and the holding time is 8 min.

[0026] Compared with existing technologies, the technical advantages achieved by this solution are as follows: the initial 60℃ hold time of 3 min is slightly longer than that of the DB-5MS column, which is beneficial for better separation of low-boiling-point volatile organic compounds such as dichloroethane, tetrachloroethylene, and styrene from solvent peaks; the heating rate of 15℃ / min is faster because the target analytes analyzed by the DB-624UI column have a relatively narrow boiling point range, and the faster heating rate can shorten the analysis time and increase throughput while ensuring resolution; the final temperature of 245℃ is sufficient to fully elute medium-boiling-point compounds such as phenols and alkyl alcohols, and the 8-min hold time ensures that all target analyte peaks are fully eluted, while avoiding increased column bleed due to excessive temperature.

[0027] To achieve the second objective of this invention, the technical solution of this invention provides an application of a method for analyzing target compounds in marine fuels that includes any of the above-mentioned technical solutions, for use in quality testing, component screening, or pollutant identification of marine fuels or biofuels.

[0028] This method is unified, simple, comprehensive, and accurate, directly serving the quality control of fuel production enterprises and helping to determine whether fuel meets specifications. It can also be used by testing institutions to screen the composition of imported or distributed marine fuels, identifying the presence of prohibited or restricted substances or abnormal additives. Furthermore, it can be used by environmental monitoring departments to trace the source of pollutants in scenarios such as fuel leaks and ship emissions. This application solution transforms laboratory analytical methods into practical industrial testing tools, yielding significant economic and social benefits.

[0029] The technical solution provided by this invention can achieve at least one of the following effects: (1) This invention realizes the unified analysis of various target compounds with different properties in marine fuel. By combining sample dilution with derivatization pretreatment, substances that originally required to be detected by different methods, such as low-boiling-point volatile organic compounds, medium-boiling-point phenols and alcohols, and high-boiling-point fatty acids and glycerides, are integrated into the same analytical process. The operation is simple and efficient, and the detection cost and cycle are significantly reduced. (2) This invention has good separation capability and quantitative accuracy. By selecting two different stationary phase chromatographic columns, DB-5MS and DB-624UI, and optimizing the programmed temperature conditions for the boiling point range of the target compounds, ideal separation results were achieved for 38 compounds on GC-MS. Combined with calibration curves with concentration ranges from 1 to 10 mg / L, the linearity is good, and the quantitative results are accurate and reliable. (3) This invention is highly practical and has a wide range of applications. This method is applicable to various sample types such as distillate oil, residual oil and bio-marine fuel. It can be used for quality testing and component screening, as well as for pollutant identification, providing a powerful technical tool for the production control, compliance inspection and environmental monitoring of marine fuel. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be discussed below. Obviously, the technical solutions described in conjunction with the accompanying drawings are only some embodiments of the present invention. For those skilled in the art, other embodiments and their accompanying drawings can be obtained based on the embodiments shown in these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the correlation of the test curve of oleic acid as the target compound in this invention. Detailed Implementation

[0032] The technical solutions of various embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments described in the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] The following reference Figure 1 The technical solutions of some embodiments of the present invention are described below.

[0034]

Example 1

[0035] S300 and GC-MS Analysis: A Shimadzu GCMS-QP2020 NX gas chromatograph-mass spectrometer was used, with DB-5MS for sample injection and analysis. The DB-5MS column temperature program was as follows: initial column temperature 60℃, held for 2 min, then ramped to 320℃ at a rate of 8℃ / min and held for 6 min. Mass spectrometry employed an electron impact ionization source with an ionization energy of 70 eV, an ion source temperature of 230℃, and a transfer line temperature of 280℃. Acquisition modes were full scan or selected ion monitoring. The target compounds were: glyceryl palmitate, 4-hexylresorcinol, phenol, o-methylphenol, 4-cinnamonol, 2-ethylphenol, stearic acid, acetophenone, m-methylphenol, 5-pentylresorcinol, and 4-methyl-1,2-benzylphenol. Phenol, palmitic acid, 1-tetradecyl alcohol, 2-ethylhexanoic acid, ginkgolic acid, 1-pentadecanol, bisphenol A, bisphenol F, 3,5-dihydroxytoluene, indene, glyceryl monostearate, oleic acid, 1,4-benzenediol, 4-ethylresorcinol, glycerol, 2,4-dimethylphenol, 4-tert-butyl-1,2-benzenediol, ginkgol, linoleic acid, p-methylphenol, 1,2-benzenediol, hexadecyl alcohol, rosin acid, glyceryl monooleate.

[0036]

Example 2

[0037] S300 and GC-MS Analysis: A Shimadzu GCMS-QP2020 NX gas chromatograph-mass spectrometer was used, with a DB-624UI column for injection analysis. The temperature program for the DB-624UI column was: initial oven temperature 60℃, held for 3 min, then ramped to 245℃ at a rate of 15℃ per min, and held for 8 min. Mass spectrometry employed an electron impact ionization source with an ionization energy of 70 eV, an ion source temperature of 230℃, and a transfer line temperature of 280℃. Acquisition modes were full scan or selected ion monitoring. The target compounds were 1,2-dichloroethane, tetrachloroethylene, styrene, and dicyclopentadiene.

[0038] Calibration method: Prepare mixed standard stock solutions of high-boiling-point target compounds and mixed standard stock solutions of low / medium-boiling-point target compounds, each with a concentration of 100 mg / L (solvent: toluene). Using a stepwise dilution method, prepare four concentration levels of calibration working solutions in toluene, with concentrations of 1 mg / L, 2 mg / L, 5 mg / L, and 10 mg / L. Take 1.0 mL of each concentration level of calibration working solution, add 150 μL of derivatization reagent, process according to the derivatization conditions of the example, and perform GC-MS analysis.

[0039] Table 1 List of 38 target compounds

[0040] The test curve for oleic acid is as follows: Figure 1 As shown in Example 1 and Example 2, calibration curves were determined for representative compounds among the 38 target compounds. The results showed that each target compound exhibited good linearity within the concentration range of 1 mg / L–10 mg / L (correlation coefficients r² were all greater than 0.998), fully demonstrating that the method of this invention has good linear response for representative components among the 38 target compounds and can meet the requirements for quantitative analysis of marine fuels.

[0041] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects. The scope of the invention is defined by the appended claims, not by the foregoing description, and thus all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0042] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for analyzing a target compound in marine fuel, characterized in that, Includes the following steps: S100. Sample preparation: Dilute the marine fuel or bio-marine fuel sample with an organic solvent to obtain the sample to be tested. S200, Derivatization: Add a derivatization reagent to the sample to be tested to carry out a derivatization reaction and obtain a derivatized sample; S300, GC-MS analysis: The derivatized sample is analyzed by GC-MS to obtain the concentration of the target compound in the sample to be tested.

2. The analytical method for the target compound in marine fuel according to claim 1, characterized in that, The target compounds include at least one of the following: glyceryl palmitate, 4-hexylresorcinol, phenol, o-methylphenol, 4-cinnamonol, 2-ethylphenol, stearic acid, acetophenone, m-methylphenol, 5-pentylresorcinol, 4-methyl-1,2-benzenehydrin, palmitic acid, 1-tetradecyl alcohol, 2-ethylhexanoic acid, ginkgolic acid, 1-pentadecanol, bisphenol A, bisphenol F, 3,5-dihydroxytoluene, styrene, indene, polycyclopentadiene, glyceryl monostearate, oleic acid, 1,4-benzenehydrin, 4-ethylresorcinol, glycerol, 2,4-dimethylphenol, 4-tert-butyl-1,2-benzenehydrin, 1,2-dichloroethane, ginkgol, tetrachloroethylene, linoleic acid, p-methylphenol, 1,2-benzenehydrin, hexadecyl alcohol, rosin acid, and glyceryl monooleate.

3. The analytical method for the target compound in marine fuel according to claim 1, characterized in that, In step S100, the organic solvent is toluene; the concentration of the sample to be tested is 1 mg / L-10 mg / L.

4. The analytical method for the target compound in marine fuel according to claim 1, characterized in that, In step S200, the derivatizing reagent is an N,O-bis(trimethylsilyl)trifluoroacetamide solution containing trimethylchlorosilane, wherein the content of trimethylchlorosilane is 1%.

5. The analytical method for the target compound in marine fuel according to claim 1, characterized in that, In step S200, the temperature of the derivatization reaction is 75℃-85℃; the time of the derivatization reaction is 50min-70min.

6. The analytical method for the target compound in marine fuel according to claim 1, characterized in that, GC analysis was performed using at least one of a first chromatographic column and a second chromatographic column, wherein the first chromatographic column was a DB-5MS column and the second chromatographic column was a DB-624UI column.

7. The method for analyzing target compounds in marine fuel according to claim 6, characterized in that, The target compounds, from highest to lowest boiling point, include: a first boiling point compound and a second boiling point compound, wherein the boiling point of the first boiling point compound is below 150°C and the boiling point of the second boiling point compound is above 150°C. The first boiling point compound is analyzed using the second chromatographic column, and the second boiling point compound is analyzed using the first chromatographic column.

8. The method for analyzing target compounds in marine fuel according to claim 7, characterized in that, The temperature program for the first chromatographic column is as follows: initial column temperature is 60℃, holding time is 2 min; heating rate is 8℃ / min; final column temperature is 320℃, holding time is 6 min.

9. The method for analyzing target compounds in marine fuel according to claim 7, characterized in that, The temperature program for the second chromatographic column is as follows: initial column temperature is 60℃, holding time is 3 min; heating rate is 15℃ / min; final column temperature is 245℃, holding time is 8 min.

10. The application of the analytical method for the target compound in marine fuel according to any one of claims 1-9, characterized in that, Used for quality testing, component screening, or contaminant identification of marine fuels or biofuels.

Images