阅读说明：本技术 一种用全二维气相色谱-氢火焰离子化检测器对柴油中多环芳烃的检测方法 (Method for detecting polycyclic aromatic hydrocarbon in diesel oil by using full two-dimensional gas chromatography-hydrogen flame ionization detector ) 是由 李红俊 赵双宏 代静 张兴军 章伟 王慧利 王文华 于 2020-09-30 设计创作，主要内容包括：本发明一种用全二维气相色谱-氢火焰离子化检测器对柴油中多环芳烃的检测方法,其特征在于该检测方法含有如下的定性分析方法：本发明还公开了定量方法。本发明提供了一种全新的分析手段,可以对柴油做一个全面的族类分析,以及对某些特定化合物进行精确测定。(The invention relates to a method for detecting polycyclic aromatic hydrocarbon in diesel oil by using a full two-dimensional gas chromatography-hydrogen flame ionization detector, which is characterized by comprising the following qualitative analysis methods: the invention also discloses a quantitative method. The invention provides a brand-new analysis means, which can perform comprehensive family analysis on diesel oil and accurately determine certain specific compounds.)

1. A method for detecting polycyclic aromatic hydrocarbon in diesel oil by using a full two-dimensional gas chromatography-hydrogen flame ionization detector is characterized by comprising the following qualitative analysis methods:

(1) the detector type is a hydrogen flame ionization detector,

(2) preparing a boundary material mixed standard solution: the boundary substance is n-decane, n-undecane, n-dodecane, n-tridecane, n-tetradecane, n-pentadecane, n-hexadecane, n-heptadecane, n-octadecane, n-nonadecane, n-eicosane, n-heneicosane, n-docosane, n-tetracosane, n-pentacosane, n-nonane, n-octane, phytane, pristane, bicyclohexane, n-octadecylbenzene, ethylbenzene, naphthalene, fluorene, 1, 2, 3, 4-tetrahydronaphthalene, octahydrophenanthrene, n-propylbenzene, n-octylbenzene, 1-methylnaphthalene, 2-ethylnaphthalene, 2-isopropylnaphthalene, dibenzofuran, phenanthrene, 9, 10-dihydrophenanthrene, 3-methylphenanthrene, indane, n-hexane as solvent, and a mixed standard solution containing 37 boundary substances is prepared;

(3) performing test analysis on the GC-FID by using the boundary substance mixed standard solution, determining one-dimensional retention time and two-dimensional retention time of each boundary substance on the map, and dividing each group; or the qualitative and family classification of the hydrocarbons in the middle distillate by GC x GC-TOFMS: and carrying out full two-dimensional gas chromatography analysis on the middle distillate, comparing the one-dimensional retention time and the two-dimensional retention time corresponding to the 37 boundary substances, identifying each hydrocarbon compound of the middle distillate and qualitatively classifying.

2. The method for detecting polycyclic aromatic hydrocarbons in diesel oil by using the full two-dimensional gas chromatography-hydrogen flame ionization detector as claimed in claim 1, wherein:

in the step (1), the temperature of the detector is 260-300 ℃; the two-dimensional modulation conditions are: the modulation column is HV (C)₅-C₃₀) (ii) a Modulator bias temperature +30/+120 ℃;

respectively taking the first 21 standard substances in a volumetric flask, using normal hexane for constant volume, preparing 21 mixed standard solutions A, taking the last 16 boundary substances to prepare standard solutions, and using normal hexane as a solvent; accurately transferring 21 boundary substance mixed standard solutions A and 16 boundary substance mixed standard solutions B into a volumetric flask respectively, and preparing 37 boundary substance mixed standard solutions with the same concentration of each boundary substance by constant volume of n-hexane; the first 21 standard substances were: n-nonane, n-octane, phytane, pristane, bicyclohexane, n-octadecyl benzene, ethylbenzene, naphthalene, fluorene, 1, 2, 3, 4-tetrahydronaphthalene, octahydrophenanthrene, n-propylbenzene, n-octylbenzene, 1-methylnaphthalene, 2-ethylnaphthalene, 2-isopropylnaphthalene, dibenzofuran, phenanthrene, 9, 10-dihydrophenanthrene, 3-methylphenanthrene, indane; the latter 16 boundary substances are n-decane, n-undecane, n-dodecane, n-tridecane, n-tetradecane, n-pentadecane, n-hexadecane, n-heptadecane, n-octadecane, n-nonadecane, n-eicosane, n-heneicosane, n-docosane, n-tetracosane, n-pentacosane;

dividing non-aromatic hydrocarbon, monocyclic aromatic hydrocarbon, bicyclic aromatic hydrocarbon and tricyclic hydrocarbon in step (3)⁺Aromatic hydrocarbons are 4 groups.

3. The method for detecting polycyclic aromatic hydrocarbons in diesel oil by using the full two-dimensional gas chromatography-hydrogen flame ionization detector as claimed in claim 1, wherein:

in the step (1), the type of the carrier gas is nitrogen and/or helium; the temperature of the sample inlet is 220-280 ℃; the flow rate of the column is 0.8-2.0 mL/min; chromatographic column and column temperature conditions: the temperature raising procedure is that the initial temperature is kept at 30-80 ℃ for 1-3min, and the temperature is raised to 260-290 ℃ at the speed of 4-8 ℃/min and kept for 3-8 min; the interface temperature of the detector is 250-300 ℃; the concentration of each boundary substance in the step (2) is 300-700 mg/L.

4. The method for detecting polycyclic aromatic hydrocarbons in diesel oil by using the full two-dimensional gas chromatography-hydrogen flame ionization detector as claimed in claim 1, wherein:

in the step (1), the conditions of a sample injection system are as follows: the sample amount is 0.5-1.5 μ L, preferably 0.5-1.2 μ L; the split ratio is 200: 1; chromatographic column and column temperature conditions: the one-dimensional chromatographic column is an SR-5ms type capillary column; the two-dimensional chromatographic column is a DB-HeavyWax type capillary column; the temperature of the detector is 260 ℃ and 300 ℃; the two-dimensional modulation conditions are: the modulation column is HV (C)₅-C₃₀) (ii) a Modulator bias temperature +30/+120 ℃; modulation period is 4-8S;

in the step (2), the concentration of each boundary substance is 500 mg/L.

5. The method for detecting polycyclic aromatic hydrocarbons in diesel oil by using the full two-dimensional gas chromatography-hydrogen flame ionization detector as claimed in claim 1, wherein:

in the step (1), the temperature of a sample inlet is 250 ℃; the column flow rate is 1.5 mL/min; the sample volume is 1 mu L; the split ratio is 200: 1; chromatographic column and column temperature conditions: the one-dimensional chromatographic column is an SR-5ms type capillary column: the column length is 30m, the outer diameter is 0.25mm, and the inner diameter is 0.25 μm; the two-dimensional chromatographic column is a DB-HeavyWax type capillary column: the column length is 0.8m, the outer diameter is 0.18mm, and the inner diameter is 0.18 μm; the temperature raising program is that the initial temperature is kept at 50 ℃ for 2min, and the temperature is raised to 275 ℃ at the speed of 6 ℃/min and kept for 5.5 min; a detector interface temperature of 280 ℃; the detector type is a hydrogen Flame Ionization Detector (FID); the temperature of the detector is 280 ℃; the two-dimensional modulation conditions are: the modulation column is HV (C)₅-C₃₀) (ii) a Modulator bias temperature +30/+120 ℃; modulation period 6S;

preparing a boundary substance mixed standard solution in the step (2): respectively weighing the first 21 standard substances in volumetric flasks, dissolving with n-hexane to obtain 21 boundary substance mixed standard solutions A of 10000 mg/L; the boundary substance mixed standard solution B is a mixed standard solution of 16 normal alkanes, the concentration of the mixed standard solution is 1000mg/L, and n-hexane is used as a solvent; accurately transferring 21 boundary substance mixed standard solutions A and 16 boundary substance mixed standard solutions B into volumetric flasks respectively, metering the volume with n-hexane, preparing 37 boundary substance mixed standard solutions with the concentration of each substance being 500mg/L, and sealing and storing at the temperature of below 0 ℃ for 1-6 months; the purity of the substance is more than or equal to 95 percent.

6. A method for detecting polycyclic aromatic hydrocarbon in diesel oil by using a full two-dimensional gas chromatography-hydrogen flame ionization detector is characterized by comprising the following quantitative analysis methods:

(1) setting sample analysis parameters; conditions of the sample injection system: the carrier gas type is nitrogen and/or helium; the temperature of the sample inlet is 220-280 ℃; the temperature of the detector is 250 ℃ and 300 ℃;

(2) making a working curve:

weighing standard substances, placing the standard substances in a volumetric flask, diluting the standard substances to a scale with n-hexane, and preparing into A, B, C, D four standard solutions;

standard substance a: 4-6 parts of n-undecane, 4-6 parts of p-xylene, 4-6 parts of 1-methylnaphthalene and 0.1-0.5 part of phenanthrene;

standard substance B: 1-3 parts of n-undecane, 1-3 parts of p-xylene, 1-3 parts of 1-methylnaphthalene and 0.1-0.18 part of phenanthrene;

standard substance C: 0.2 to 0.8 weight portion of n-undecane, 0.2 to 0.8 weight portion of p-xylene, 0.2 to 0.8 weight portion of 1-methylnaphthalene and 0.02 to 0.06 weight portion of phenanthrene;

standard substance D: 0.03-0.2 part of n-undecane, 0.05-0.2 part of p-xylene, 0.05-0.2 part of 1-methylnaphthalene and 0.005-0.02 part of phenanthrene;

respectively adding into a standard solution A, B, C, D, recording peak areas of each standard substance of the two-dimensional map, and plotting the peak areas by using the concentration of each aromatic hydrocarbon standard substance;

(3) and (3) determining a sample: sampling a sample solution, and collecting two-dimensional gas chromatography data;

(4) and (3) calculating the content, namely respectively carrying out quantitative analysis on the compounds of each group in the middle distillate by adopting an external standard method and/or a peak area normalization method.

7. The method of claim 6, wherein the polycyclic aromatic hydrocarbon in diesel is detected by a full two-dimensional gas chromatography-hydrogen flame ionization detector

The conditions of the sample injection system in the step (1) are as follows: the carrier gas type is nitrogen and/or helium; the temperature of the sample inlet is 220-280 ℃; the flow rate of the column is 0.5-2 mL/min; the sample injection amount is 0.5-1.5 mu L;

chromatographic column and column temperature conditions: the temperature raising procedure is that the initial temperature is kept at 30-70 ℃ for 1-5min, and the temperature is raised to 250-300 ℃ at the speed of 2-8 ℃/min and kept for 2-8 min; the two-dimensional modulation conditions are: modulator bias temperature +30/+120 ℃; modulation period is 3-10S;

step (2) making a working curve: respectively entering standard solutions A, B, C, D after the conditions in the step (1) are stable, recording peak areas of all standard substances of a two-dimensional map, and plotting the peak areas by using the concentrations of all aromatic hydrocarbon standard substances, wherein the correlation coefficient is larger than 0.999;

(3) and (3) determining a sample: transferring a sample into a chromatographic bottle, injecting a sample solution after the conditions in the step (1) are stable, and collecting two-dimensional gas chromatography data;

(4) and (3) calculating the content, namely respectively carrying out quantitative analysis on the compounds of each group in the middle distillate by adopting an external standard method and/or a peak area normalization method.

8. The method for detecting polycyclic aromatic hydrocarbons in diesel oil by using the comprehensive two-dimensional gas chromatography-hydrogen flame ionization detector as claimed in claim 6, wherein the method comprises the following steps:

step (1), the carrier gas type is nitrogen/helium; the temperature of a sample inlet is 250 ℃; the column flow rate is 1.5 mL/min; the sample volume is 1 mu L; the split ratio is 200: 1; the one-dimensional chromatographic column is an SR-5ms type capillary column: the column length is 30m, the outer diameter is 0.25mm, and the inner diameter is 0.25 μm; the two-dimensional chromatographic column is a DB-HeavyWax type capillary column: the column length is 0.8m, the outer diameter is 0.18mm, and the inner diameter is 0.18 μm; the temperature raising program is that the initial temperature is kept at 50 ℃ for 2min, and the temperature is raised to 275 ℃ at the speed of 6 ℃/min and kept for 5.5 min; a detector interface temperature of 280 ℃; setting the detection system conditions: the detector type is a hydrogen Flame Ionization Detector (FID); the temperature of the detector is 280 ℃;

the two-dimensional modulation conditions are: the modulation column is HV (C)₅-C₃₀) (ii) a Modulator bias temperature +30/+120 ℃; modulation period 6S;

in the step (2), weighing standard substances, placing the standard substances in a volumetric flask with 100 parts by volume, diluting the standard substances to a scale with n-hexane, and preparing A, B, C, D four standard solutions; the normal hexane is chromatographically pure;

standard substance a: 5 parts of n-undecane, 5 parts of p-xylene, 5 parts of 1-methylnaphthalene and 0.3 part of phenanthrene;

standard substance B: 2.5 parts of n-undecane, 2.5 parts of p-xylene, 2.5 parts of 1-methylnaphthalene and 0.15 part of phenanthrene;

standard substance C: 0.5 part of n-undecane, 0.5 part of p-xylene, 0.5 part of 1-methylnaphthalene and 0.03 part of phenanthrene;

standard substance D: 0.1 part of n-undecane, 0.1 part of p-xylene, 0.1 part of 1-methylnaphthalene and 0.01 part of phenanthrene;

step (1) the conditions are stableAfter the determination, respectively adding 1 mu L of standard solution A, B, C, D, recording the peak area of each standard substance of the two-dimensional map, and drawing the peak area by using each aromatic hydrocarbon standard substance, wherein the correlation coefficient is more than 0.999; in the step (4), each group comprises non-aromatic hydrocarbon, monocyclic aromatic hydrocarbon, bicyclic aromatic hydrocarbon and tricyclic aromatic hydrocarbon⁺An aromatic hydrocarbon.

9. The method for detecting polycyclic aromatic hydrocarbons in diesel oil by using the comprehensive two-dimensional gas chromatography-hydrogen flame ionization detector as claimed in claim 6, wherein the method comprises the following steps:

the external standard curve method comprises the following steps:

non-aromatic hydrocarbons, and/or monocyclic aromatic hydrocarbons, and/or bicyclic aromatic hydrocarbons, and/or tricyclic aromatic hydrocarbons⁺The mass fraction of aromatic hydrocarbons is calculated according to formula (1):

ω_i＝[(A×S)+I]………………………………………(1)

in the formula:

ω_inon-aromatic, monocyclic, bicyclic and tricyclic aromatic hydrocarbons⁺Mass fraction of aromatic hydrocarbons, expressed in percentage;

a-non-aromatic or monocyclic or bicyclic or tricyclic aromatic hydrocarbons⁺Peak area of aromatic hydrocarbon;

s-non-aromatic or monocyclic aromatic or bicyclic aromatic or tricyclic⁺Slope of the operating curve for aromatics (% m/v vs. peak area);

i-non-aromatic or monocyclic aromatic or bicyclic aromatic or tricyclic⁺The intercept of the operating curve of the aromatic;

the peak area normalization method comprises the following steps:

calculating non-aromatic hydrocarbon, and/or monocyclic aromatic hydrocarbon, and/or bicyclic aromatic hydrocarbon, and/or tricyclic aromatic hydrocarbon according to formula (2)⁺Mass fraction of aromatic hydrocarbons ω_i[% (mass fraction)]：

In the formula:

ω_inon-aromatic, monocyclic, bicyclic and tricyclic aromatic hydrocarbons⁺Mass fraction of aromatic hydrocarbons, expressed in percentage;

A_inon-aromatic, monocyclic, bicyclic and tricyclic aromatic hydrocarbons⁺Peak area values of aromatic hydrocarbons;

∑A_i-sum of peak area values of the components.

10. The method for detecting polycyclic aromatic hydrocarbons in diesel oil by using the comprehensive two-dimensional gas chromatography-hydrogen flame ionization detector as claimed in claim 6, wherein the method comprises the following steps: the method also comprises a method for calculating the content of polycyclic aromatic hydrocarbon, and/or a method for calculating the content of total aromatic hydrocarbon, and/or a method for calculating the content of hydrocarbon:

the content calculation method of the polycyclic aromatic hydrocarbon comprises the following steps:

calculating the polycyclic aromatic hydrocarbon content omega by the formula (3)₁[% (mass fraction)]：

The method for calculating the content of the total aromatic hydrocarbon comprises the following steps:

the total aromatic content omega was calculated from the formula (4)₂[% (mass fraction)]：

The hydrocarbon content calculation method comprises the following steps:

the sum of the contents of the hydrocarbons is used to obtain (non-aromatic hydrocarbon + monocyclic aromatic hydrocarbon + bicyclic aromatic hydrocarbon + tricyclic hydrocarbon)⁺Aromatic hydrocarbons).

Technical Field

The invention belongs to the field of detection methods of polycyclic aromatic hydrocarbons in diesel oil, and particularly relates to a method for detecting polycyclic aromatic hydrocarbons in diesel oil by using a full-two-dimensional gas chromatography-hydrogen flame ionization detector.

Background

The aromatic content in diesel fuel is one of the factors that affect exhaust emissions and fuel combustion performance (expressed in terms of cetane number). With the increasing strictness of the requirements on environmental protection, the requirements on the content of total aromatic hydrocarbons, especially polycyclic aromatic hydrocarbons, in diesel oil become stricter, and therefore, an accurate analysis method is required to determine the content of the total aromatic hydrocarbons and the content of the polycyclic aromatic hydrocarbons in the product. The existing main method is as follows:

GB/T11132 is used to determine aromatics in diesel but is not suitable for cuts boiling above 315 ℃ and is less accurate. SH/T0606 can be used for measuring total aromatic hydrocarbon and polycyclic aromatic hydrocarbon in diesel oil or aviation kerosene, but the analysis cost is high and the time is consumed, particularly, the difference between the results of two chromatographic analysis measurements of saturated hydrocarbon and aromatic hydrocarbon fractions is only required to be less than 1.2%, and the method has low precision compared with the limit value of aromatic hydrocarbon content (mass fraction) less than or equal to 1% in GB/T29720 and GB/T31090. ASTM D5186 can also measure total aromatics and polycyclic aromatics in diesel or aviation kerosene, but it uses less supercritical fluid chromatography equipment and is not widely used. SH/T0806 can also measure total aromatic hydrocarbon and polycyclic aromatic hydrocarbon in diesel oil, but sulfur, nitrogen and oxygen-containing compounds, conjugated diene and conjugated polyene have influence on the measurement result; fatty Acid Methyl Esters (FAME) interfere with the determination of tricyclic + aromatics; the differential refraction detector is sensitive to the environment, particularly the temperature and the airflow, and the test result is greatly influenced by the slight change of the environment; the single analysis has large mobile phase consumption and higher analysis cost; the instrument is stable, the analysis and inspection time is long, and the timeliness is poor. The existing experiments prove that when the methods of SH/T0806 and SH/T0606 are respectively adopted to prepare the same quality control sample, the difference of the results is about 1%. In conclusion, the existing methods have complicated procedures and unsatisfactory effects, and each method can only be used for one or one type of substances.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention discloses a method for detecting polycyclic aromatic hydrocarbon in diesel oil by using a full two-dimensional gas chromatography-hydrogen flame ionization detector.

In order to achieve the purpose, the technical scheme of the invention is as follows:

a method for detecting polycyclic aromatic hydrocarbon in diesel oil by using a full two-dimensional gas chromatography-hydrogen flame ionization detector comprises the following qualitative analysis methods:

(1) the detector type is a hydrogen flame ionization detector,

(2) preparing a boundary material mixed standard solution: the boundary substance is n-decane, n-undecane, n-dodecane, n-tridecane, n-tetradecane, n-pentadecane, n-hexadecane, n-heptadecane, n-octadecane, n-nonadecane, n-eicosane, n-heneicosane, n-docosane, n-tetracosane, n-pentacosane, n-nonane, n-octane, phytane, pristane, bicyclohexane, n-octadecylbenzene, ethylbenzene, naphthalene, fluorene, 1, 2, 3, 4-tetrahydronaphthalene, octahydrophenanthrene, n-propylbenzene, n-octylbenzene, 1-methylnaphthalene, 2-ethylnaphthalene, 2-isopropylnaphthalene, dibenzofuran, phenanthrene, 9, 10-dihydrophenanthrene, 3-methylphenanthrene, indane, n-hexane as solvent, and a mixed standard solution containing 37 boundary substances is prepared.

(3) Performing test analysis on the GC-FID by using the boundary substance mixed standard solution, determining one-dimensional retention time and two-dimensional retention time of each boundary substance on the map, and dividing each group; or the qualitative and family classification of the hydrocarbons in the middle distillate by GC x GC-TOFMS: and carrying out full two-dimensional gas chromatography analysis on the middle distillate, comparing the one-dimensional retention time and the two-dimensional retention time corresponding to the 37 boundary substances, identifying each hydrocarbon compound of the middle distillate and qualitatively classifying.

Further, in the above-mentioned case,

in the step (1), the temperature of the detector is 260-300 ℃; the two-dimensional modulation conditions are: the modulation column is HV (C)₅-C₃₀) (ii) a Modulator bias temperature +30/+120 ℃;

respectively taking the first 21 standard substances in a volumetric flask, using normal hexane for constant volume, preparing 21 mixed standard solutions A, taking the last 16 boundary substances to prepare standard solutions, and using normal hexane as a solvent; accurately transferring 21 boundary substance mixed standard solutions A and 16 boundary substance mixed standard solutions B into a volumetric flask respectively, and preparing 37 boundary substance mixed standard solutions with the same concentration of each boundary substance by constant volume of n-hexane; the first 21 standard substances were: n-nonane, n-octane, phytane, pristane, bicyclohexane, n-octadecyl benzene, ethylbenzene, naphthalene, fluorene, 1, 2, 3, 4-tetrahydronaphthalene, octahydrophenanthrene, n-propylbenzene, n-octylbenzene, 1-methylnaphthalene, 2-ethylnaphthalene, 2-isopropylnaphthalene, dibenzofuran, phenanthrene, 9, 10-dihydrophenanthrene, 3-methylphenanthrene, indane; the latter 16 boundary substances are n-decane, n-undecane, n-dodecane, n-tridecane, n-tetradecane, n-pentadecane, n-hexadecane, n-heptadecane, n-octadecane, n-nonadecane, n-eicosane, n-heneicosane, n-docosane, n-tetracosane, n-pentacosane;

dividing non-aromatic hydrocarbon, monocyclic aromatic hydrocarbon, bicyclic aromatic hydrocarbon and tricyclic hydrocarbon in step (3)⁺Aromatic hydrocarbons are 4 groups.

Preferably, the first and second liquid crystal materials are,

in the step (1), the type of the carrier gas is nitrogen and/or helium; the temperature of the sample inlet is 220-280 ℃; the flow rate of the column is 0.8-2.0 mL/min; chromatographic column and column temperature conditions: the temperature raising procedure is that the initial temperature is kept at 30-80 ℃ for 1-3min, and the temperature is raised to 260-290 ℃ at the speed of 4-8 ℃/min and kept for 3-8 min; the interface temperature of the detector is 250-300 ℃;

the concentration of each boundary substance in the step (2) is 300-700 mg/L.

Further, in the above-mentioned case,

in the step (1), the conditions of a sample injection system are as follows: the sample amount is 0.5-1.5 μ L, preferably 0.5-1.2 μ L; the split ratio is 200: 1; chromatographic column and column temperature conditions: the one-dimensional chromatographic column is an SR-5ms type capillary column; the two-dimensional chromatographic column is a DB-HeavyWax type capillary column; the temperature of the detector is 260 ℃ and 300 ℃; the two-dimensional modulation conditions are: the modulation column is HV (C)₅-C₃₀) (ii) a Modulator bias temperature +30/+120 ℃; modulation period is 4-8S;

in the step (2), the concentration of each boundary substance is 500 mg/L.

Preferably, the first and second liquid crystal materials are,

in the step (1), the temperature of a sample inlet is 250 ℃; the column flow rate is 1.5 mL/min; the sample volume is 1 mu L; the split ratio is 200: 1; chromatographic column and column temperature conditions: the one-dimensional chromatographic column is an SR-5ms type capillary column: the column length is 30m, the outer diameter is 0.25mm, and the inner diameter is 0.25 μm; the two-dimensional chromatographic column is a DB-HeavyWax type capillary column: the column length is 0.8m, the outer diameter is 0.18mm, and the inner diameter is 0.18 μm; the temperature raising program is that the initial temperature is kept at 50 ℃ for 2min, and the temperature is raised to 275 ℃ at the speed of 6 ℃/min and kept for 5.5 min; a detector interface temperature of 280 ℃; the detector type is a hydrogen Flame Ionization Detector (FID); the temperature of the detector is 280 ℃; the two-dimensional modulation conditions are: the modulation column is HV (C)₅-C₃₀) (ii) a Modulator bias temperature +30/+120 ℃; modulation period 6S;

preparing a boundary substance mixed standard solution in the step (2): respectively weighing the first 21 standard substances in volumetric flasks, dissolving with n-hexane to obtain 21 boundary substance mixed standard solutions A of 10000 mg/L; the boundary substance mixed standard solution B is a mixed standard solution of 16 normal alkanes, the concentration of the mixed standard solution is 1000mg/L, and n-hexane is used as a solvent; accurately transferring 21 boundary substance mixed standard solutions A and 16 boundary substance mixed standard solutions B into volumetric flasks respectively, metering the volume with n-hexane, preparing 37 boundary substance mixed standard solutions with the concentration of each substance being 500mg/L, and sealing and storing at the temperature of below 0 ℃ for 1-6 months; the purity of the substance is more than or equal to 95 percent.

A method for detecting polycyclic aromatic hydrocarbon in diesel oil by using a full two-dimensional gas chromatography-hydrogen flame ionization detector comprises the following quantitative analysis methods:

(1) setting sample analysis parameters; conditions of the sample injection system: the carrier gas type is nitrogen and/or helium; the temperature of the sample inlet is 220-280 ℃; the temperature of the detector is 250 ℃ and 300 ℃;

(2) making a working curve:

weighing standard substances, placing the standard substances in a volumetric flask, diluting the standard substances to a scale with n-hexane, and preparing into A, B, C, D four standard solutions;

standard substance a: 4-6 parts of n-undecane, 4-6 parts of p-xylene, 4-6 parts of 1-methylnaphthalene and 0.1-0.5 part of phenanthrene;

standard substance B: 1-3 parts of n-undecane, 1-3 parts of p-xylene, 1-3 parts of 1-methylnaphthalene and 0.1-0.18 part of phenanthrene;

standard substance C: 0.2 to 0.8 weight portion of n-undecane, 0.2 to 0.8 weight portion of p-xylene, 0.2 to 0.8 weight portion of 1-methylnaphthalene and 0.02 to 0.06 weight portion of phenanthrene;

standard substance D: 0.03-0.2 part of n-undecane, 0.05-0.2 part of p-xylene, 0.05-0.2 part of 1-methylnaphthalene and 0.005-0.02 part of phenanthrene;

respectively adding into a standard solution A, B, C, D, recording peak areas of each standard substance of the two-dimensional map, and plotting the peak areas by using the concentration of each aromatic hydrocarbon standard substance;

(3) and (3) determining a sample: sampling a sample solution, and collecting two-dimensional gas chromatography data;

(4) and (3) calculating the content, namely respectively carrying out quantitative analysis on the compounds of each group in the middle distillate by adopting an external standard method and/or a peak area normalization method.

Further, in the above-mentioned case,

the conditions of the sample injection system in the step (1) are as follows: the carrier gas type is nitrogen and/or helium; the temperature of the sample inlet is 220-280 ℃; the flow rate of the column is 0.5-2 mL/min; the sample injection amount is 0.5-1.5 mu L;

chromatographic column and column temperature conditions: the temperature raising procedure is that the initial temperature is kept at 30-70 ℃ for 1-5min, and the temperature is raised to 250-300 ℃ at the speed of 2-8 ℃/min and kept for 2-8 min; the two-dimensional modulation conditions are: modulator bias temperature +30/+120 ℃; modulation period is 3-10S;

step (2) making a working curve: respectively entering standard solutions A, B, C, D after the conditions in the step (1) are stable, recording peak areas of all standard substances of a two-dimensional map, and plotting the peak areas by using the concentrations of all aromatic hydrocarbon standard substances, wherein the correlation coefficient is larger than 0.999;

(3) and (3) determining a sample: transferring a sample into a chromatographic bottle, injecting a sample solution after the conditions in the step (1) are stable, and collecting two-dimensional gas chromatography data;

(4) and (3) calculating the content, namely respectively carrying out quantitative analysis on the compounds of each group in the middle distillate by adopting an external standard method and/or a peak area normalization method.

Preferably, the first and second liquid crystal materials are,

step (1), the carrier gas type is nitrogen/helium; the temperature of a sample inlet is 250 ℃; the column flow rate is 1.5 mL/min; the sample volume is 1 mu L; the split ratio is 200: 1; the one-dimensional chromatographic column is an SR-5ms type capillary column: the column length is 30m, the outer diameter is 0.25mm, and the inner diameter is 0.25 μm; the two-dimensional chromatographic column is a DB-HeavyWax type capillary column: the column length is 0.8m, the outer diameter is 0.18mm, and the inner diameter is 0.18 μm; the temperature raising program is that the initial temperature is kept at 50 ℃ for 2min, and the temperature is raised to 275 ℃ at the speed of 6 ℃/min and kept for 5.5 min; a detector interface temperature of 280 ℃; setting the detection system conditions: the detector type is a hydrogen Flame Ionization Detector (FID); the temperature of the detector is 280 ℃;

the two-dimensional modulation conditions are: the modulation column is HV (C)₅-C₃₀) (ii) a Modulator bias temperature +30/+120 ℃; modulation period 6S;

in the step (2), weighing standard substances, placing the standard substances in a volumetric flask with 100 parts by volume, diluting the standard substances to a scale with n-hexane, and preparing A, B, C, D four standard solutions; the normal hexane is chromatographically pure;

standard substance a: 5 parts of n-undecane, 5 parts of p-xylene, 5 parts of 1-methylnaphthalene and 0.3 part of phenanthrene;

standard substance B: 2.5 parts of n-undecane, 2.5 parts of p-xylene, 2.5 parts of 1-methylnaphthalene and 0.15 part of phenanthrene;

standard substance C: 0.5 part of n-undecane, 0.5 part of p-xylene, 0.5 part of 1-methylnaphthalene and 0.03 part of phenanthrene;

standard substance D: 0.1 part of n-undecane, 0.1 part of p-xylene, 0.1 part of 1-methylnaphthalene and 0.01 part of phenanthrene;

after the conditions in the step (1) are stable, respectively feeding 1 mu L of standard solution A, B, C, D, recording the peak area of each standard substance of the two-dimensional map, and plotting the peak area by using each aromatic hydrocarbon standard substance, wherein the correlation coefficient is more than 0.999;

in the step (4), each group comprises non-aromatic hydrocarbon, monocyclic aromatic hydrocarbon, bicyclic aromatic hydrocarbon and tricyclic aromatic hydrocarbon⁺An aromatic hydrocarbon.

The method for detecting the polycyclic aromatic hydrocarbon in the diesel oil by using the full two-dimensional gas chromatography-hydrogen flame ionization detector comprises the following steps:

non-aromatic hydrocarbon, and-Or monocyclic, and/or bicyclic, and/or tricyclic aromatic hydrocarbons⁺The mass fraction of aromatic hydrocarbons is calculated according to formula (1):

ω_i＝[(A×S)+I]………………………………………(1)

in the formula:

ω_inon-aromatic, monocyclic, bicyclic and tricyclic aromatic hydrocarbons⁺Mass fraction of aromatic hydrocarbons, expressed in percentage;

a-non-aromatic or monocyclic or bicyclic or tricyclic aromatic hydrocarbons⁺Peak area of aromatic hydrocarbon;

s-non-aromatic or monocyclic aromatic or bicyclic aromatic or tricyclic⁺Slope of the operating curve for aromatics (% m/v vs. peak area);

i-non-aromatic or monocyclic aromatic or bicyclic aromatic or tricyclic⁺The intercept of the operating curve of the aromatic;

the peak area normalization method comprises the following steps:

calculating non-aromatic hydrocarbon, and/or monocyclic aromatic hydrocarbon, and/or bicyclic aromatic hydrocarbon, and/or tricyclic aromatic hydrocarbon according to formula (2)⁺Mass fraction of aromatic hydrocarbons ω_i[% (mass fraction)]：

In the formula:

ω_inon-aromatic, monocyclic, bicyclic and tricyclic aromatic hydrocarbons⁺Mass fraction of aromatic hydrocarbons, expressed in percentage; a. the_iNon-aromatic, monocyclic, bicyclic and tricyclic aromatic hydrocarbons⁺Peak area values of aromatic hydrocarbons;

∑A_i-sum of peak area values of the components;

this calculation process may also be performed by the data processing system.

The method for detecting the polycyclic aromatic hydrocarbon in the diesel oil by using the full two-dimensional gas chromatography-hydrogen flame ionization detector also comprises a polycyclic aromatic hydrocarbon content calculation method, and/or a total aromatic hydrocarbon content calculation method, and/or a hydrocarbon content calculation method:

the content calculation method of the polycyclic aromatic hydrocarbon comprises the following steps:

calculating the polycyclic aromatic hydrocarbon content omega by the formula (3)₁[% (mass fraction)]：

ω₁＝ω_{Bicyclic aromatic hydrocarbons}+ω_{Tricyclic + aromatic hydrocarbons}………………………………(3)；

The method for calculating the content of the total aromatic hydrocarbon comprises the following steps:

the total aromatic content omega was calculated from the formula (4)₂[% (mass fraction)]：

ω₂＝ω_{Monocyclic aromatic hydrocarbon}+ω_{Bicyclic aromatic hydrocarbons}+ω_{Tricyclic + aromatic hydrocarbons}…………………………………(4)

The hydrocarbon content calculation method comprises the following steps:

the sum of the contents of the hydrocarbons is used to obtain (non-aromatic hydrocarbon + monocyclic aromatic hydrocarbon + bicyclic aromatic hydrocarbon + tricyclic hydrocarbon)⁺Aromatic hydrocarbons).

The terms and definitions of the present invention are as follows:

comprehensive two-dimensional gas chromatography (GCxGC)

Two chromatographic columns with different separation mechanisms and mutually independent are connected in series through a modulator to form a two-dimensional gas chromatographic system. Fractions after one-dimensional separation of the first chromatographic column sequentially enter a modulator for capturing and focusing, then are conveyed to the second chromatographic column for two-dimensional separation, and then enter a detector, so that a three-dimensional chromatogram (a 3D (three-dimensional) graph or a two-dimensional profile graph with one-dimensional retention time, two-dimensional retention time and signal intensity as coordinates is obtained.

One-dimensional retention time 1st dimension coverage time

The time from the beginning of the sample feeding to the time when the component concentration is maximum after the first chromatographic column, i.e. the time from the beginning of the sample feeding to the time when the peak of a certain component chromatographic peak appears on the first chromatographic column, is called the one-dimensional retention time of the component, and is taken as the X axis on the full two-dimensional chart, and the minute (min) or the second(s) is taken as the time unit.

Two-dimensional retention time 2nd dimension retention time

The time from the start of the transmission of the sample component by the modulator to the second chromatographic column to the time at which the concentration maximum of the component occurs after the second chromatographic column, i.e., the time from the start of the transmission of the modulator to the second chromatographic column to the time at which the peak of a certain component occurs on the second chromatographic column, is referred to as the two-dimensional retention time of this component, on the two-dimensional plots as the Y-axis, in seconds(s).

Contour plot GCxGC color contourer chromanogran

And (3) a compound distribution plan displayed after series signal data output by the comprehensive two-dimensional gas chromatograph is processed by a computer. The abscissa of the profile is the one-dimensional retention time, and the ordinate is the two-dimensional retention time, wherein the dots represent the compounds, and the concentration of the compounds is indicated by the shade of the color.

Bicyclic aromatic di-aromatic hydrocarbons (DAHs)

In the present process, compounds are defined that have longer retention times in one and two dimensions than most monocyclic aromatics.

1.1 monocyclic aromatic mono-aromatic hydrocarbons (MAHs)

In the present process, compounds are defined that have one-dimensional and two-dimensional retention times longer than most non-aromatic hydrocarbons but shorter than most bicyclic aromatic hydrocarbons.

1.2 non-aromatic hydrocarbons

In the present process, compounds are defined that have shorter retention times in one and two dimensions than most monocyclic aromatics.

1.3 polycyclic aromatic hydrocarbons polycychc aromatic hydrocarbons (POLY-AHs)

In this process, bicyclic aromatic hydrocarbons (DAHs) and tricyclic aromatic hydrocarbons (SAHs) are defined⁺Sum of aromatic hydrocarbons (T + AHs).

1.4 Total aromatic hydrocarbons

In this process, Monocyclic Aromatic Hydrocarbons (MAHs), bicyclic aromatic hydrocarbons (DAHs) and tricyclic aromatic hydrocarbons (SAHs) are defined⁺Sum of aromatic hydrocarbons (T + AHs).

1.5 tricyclic ring⁺Aromatic hydrocarbon tri⁺-aromatic hydrocarbons(T+AHs)

In the present process, compounds are defined that have longer retention times in one and two dimensions than most bicyclic aromatic hydrocarbons.

1.6 group race

In the method, compounds with similar chemical structures are defined.

1.7 boundary Material

In the present method, a substance for dividing the boundaries of each group of regions is defined.

Peak area of group 1.8

In the present method, it is defined as the sum of the peak areas of all compounds in each of the identified groups.

The invention has the beneficial effects that:

the invention discloses a new method for carrying out qualitative and quantitative analysis on polycyclic aromatic hydrocarbon in diesel oil by a full two-dimensional gas chromatography-hydrogen flame ionization detector (GC x GC-FID). compared with an SH/T0806 arbitration method, the response difference of different substances, particularly substances of the same family on the FID detector is far lower than that of a differential refraction detector, so that the determination result is more accurate. The method comprises the steps of firstly, acquiring diesel data by adopting a full two-dimensional gas chromatography-time-of-flight mass spectrum (GC x GC-TOFMS), and identifying and classifying hydrocarbon compounds according to retention time, mass spectrum information and substance structural characteristics of each compound on a (GC x GC-TOFMS) full ion current spectrum. A total of 37 boundary materials were identified for 4 families. And then, respectively collecting data of 37 boundary substances and prepared 37 boundary substance mixed standard solutions (about 500mg/L) on GC x GC-FID (analysis conditions are shown in table 1), determining one-dimensional retention time and two-dimensional retention time of each boundary substance according to a determination result, and realizing the direct characterization of polycyclic aromatic hydrocarbons (bicyclic + tricyclic + or more) in diesel oil on a full two-dimensional gas chromatography (GC x GC-FID) by fully relying on the marking action of the boundary substances, so that the limitation of relying on GC x GC-TOFMS on the diesel oil characterization is eliminated, and the quantitative method adopts an external standard method and a peak volume normalization method. The method not only comprehensively inspects the repeatability and the accuracy of the method, but also compares the repeatability and the accuracy with the existing arbitration method SH/T0806-2008, and inspects the influence of the oxygen-containing compound on the qualitative and quantitative analysis of the polycyclic aromatic hydrocarbon in the diesel oil.

The common oxygen-containing compounds only interfere the determination of non-aromatic hydrocarbons and monocyclic aromatic hydrocarbons in diesel oil, and do not interfere the determination of polycyclic aromatic hydrocarbons (bicyclic + tricyclic +). Meanwhile, the test also proves that the Fatty Acid Methyl Ester (FAME) in the method has no influence on the determination of the tricyclic + aromatic hydrocarbon.

The research establishes a new method for qualitatively and quantitatively analyzing the polycyclic aromatic hydrocarbon in the diesel oil by using a full two-dimensional gas chromatography-hydrogen flame ionization detector (GC x GC-FID). More precisely, the octahydrophenanthrene and/or CnH2n-10 compounds belong to monocyclic aromatic hydrocarbons. Two quantitative methods, namely an external standard method and a peak volume normalization method, are researched. It was confirmed that the oxygenates and fatty acid methyl esters do not interfere with the quantification of polycyclic aromatic hydrocarbons. Meanwhile, the precision and accuracy of the method are examined and compared with the SH/T0806-2008 arbitration method. The results show that: the method can accurately obtain the composition information of the polycyclic aromatic hydrocarbon in the diesel oil, and simultaneously, the quantitative result has high consistency compared with SH/T0806-2008, and the method has better anti-interference performance and wider application range. Provides an effective method for the precise separation and rapid quantification of polycyclic aromatic hydrocarbon components in diesel oil fractions.

The invention innovatively researches and prepares the boundary substance mixed standard solution for the first time, gets rid of the process of qualitatively analyzing detection data on a full two-dimensional gas chromatography-time-of-flight mass spectrum (GC × GC-TOFMS), and realizes the qualitative and quantitative analysis of polycyclic aromatic hydrocarbons (bicyclic + tricyclic + or more) in diesel oil fractions on the full two-dimensional gas chromatography (GC × GC-FID) directly. The method avoids the condition that the hydrocarbon quantification is inaccurate due to the large difference of the refractive indexes of different hydrocarbon compounds or the ionization effects of EI ionization sources when the hydrocarbon content of the middle distillate is measured by other methods, and simultaneously, the method has simple experimental process and low analysis cost.

A new method for separating and measuring the hydrocarbon composition of the middle fraction by GC-FID is established. More precisely, the octahydrophenanthrene and/or CnH2n-10 compounds belong to monocyclic aromatic hydrocarbons. The method can accurately obtain the composition information of the polycyclic aromatic hydrocarbon in the diesel oil, and simultaneously, the quantitative result has high consistency compared with SH/T0806-2008, and the method has better anti-interference performance and wider application range. Provides an effective method for the accurate separation and rapid quantification of hydrocarbon components in the middle distillate.

The appearance of the full two-dimensional gas chromatography technology provides a brand-new analysis means, can perform comprehensive family analysis on diesel oil, and can accurately determine certain specific compounds.

Drawings

FIG. 1, a full two-dimensional chromatogram profile (TIC chart) of diesel;

FIG. 2 is a two-dimensional profile of a 37 ethnic boundary mixed standard solution;

FIG. 3 is a graph showing the results of analysis of three boundary substances, indane, tetrahydronaphthalene and octahydrophenanthrene, by SH/T0806;

FIG. 4 is a trend graph of the quantitative results of the three methods;

FIG. 5, GCXGC-FID and SH/T0806-2008 analyze relative error of quantitative result of polycyclic aromatic hydrocarbon in diesel oil;

FIG. 6, 22 kinds of oxygen compounds mix the two-dimentional outline map of the mark;

FIG. 7 is a two-dimensional profile of fatty acid methyl esters.

Detailed Description

The following description is only exemplary of the present invention and should not be construed as limiting the scope of the present invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention should be included in the scope of the present invention.

EXAMPLE one qualitative analysis of polycyclic aromatic hydrocarbons in Diesel oil

1 conditions of the apparatus

TABLE 1 typical all-two-dimensional gas chromatography conditions

2, qualitative analysis, namely firstly preparing a mixed standard solution containing 37 boundary substances, analyzing the mixed standard solution by a full two-dimensional gas chromatograph, and identifying the mixed standard solution on a GC x GC-FID chromatogramThe one-dimensional retention time and the two-dimensional retention time corresponding to 37 boundary substances are distinguished, and non-aromatic hydrocarbon, cyclic aromatic hydrocarbon, bicyclic aromatic hydrocarbon and tricyclic aromatic hydrocarbon are distinguished⁺Aromatic hydrocarbons are 4 groups. And carrying out full two-dimensional gas chromatography analysis on the middle distillate, comparing the one-dimensional retention time and the two-dimensional retention time corresponding to the 37 boundary substances, identifying each hydrocarbon compound of the middle distillate and qualitatively classifying.

2.1 preparation of boundary Material Mixed Standard solution

The boundary substance mixed standard solution is prepared by mixing a boundary substance mixed standard solution A and a boundary substance mixed standard solution B according to a certain proportion, and the specific preparation method comprises the following steps:

(1) reagent

The purity of the boundary substances is more than 95%. Except 16 normal paraffin mixed standard solutions, the other solutions are pure products.

The concentration of 16 kinds of mixed standard solutions of normal paraffins (16 kinds of paraffins include n-decane, n-undecane, n-dodecane, n-tridecane, n-tetradecane, n-pentadecane, n-hexadecane, n-heptadecane, n-octadecane, n-nonadecane, n-eicosane, n-heneicosane, n-docosane, n-tricosane, n-tetracosane, and n-pentacosane) was 1000 mg/L.

(2) Preparation of solutions

a) 21 kinds of boundary material solution A.

Weigh 0.02g (to the nearest 0.001g) of the material in Table 2 separately into 2mL volumetric flasks and hold the volume with chromatographically pure hexane. 21 mixed standard solutions A of 10000mg/L are prepared.

Table 222 boundary material information table

b) Preparation of boundary Material Mixed Standard solution B

Boundary substance mixed standard solution B was a purchased mixed standard solution of 16 kinds of n-alkanes (16 kinds of n-alkanes include n-decane, n-undecane, n-dodecane, n-tridecane, n-tetradecane, n-pentadecane, n-hexadecane, n-heptadecane, n-octadecane, n-nonadecane, n-eicosane, n-heneicosane, n-docosane, n-tricosane, n-tetracosane, n-pentacosane), the concentration was 1000mg/L, and n-hexane was used as a solvent.

c) Preparation of 37 kinds of boundary substance mixed standard solution

And accurately transferring 21 boundary substance mixed standard solutions A0.1mL and 16 boundary substance mixed standard solutions B1mL into a 2ml volumetric flask, and preparing the boundary substance mixed standard solutions with the substance concentrations of 500mg/L by using chromatographically pure hexane for constant volume. Sealing and storing at-20 deg.C for 3 months.

2.2 division of groups

After the gas phase operating conditions had stabilized, 1. mu.L of the boundary material mixed standard solution (2.1) was subjected to test analysis on GC XGC-FID (see Table 1). Determining the one-dimensional retention time and the two-dimensional retention time of each boundary substance on the map, and dividing non-aromatic hydrocarbon, monocyclic aromatic hydrocarbon, bicyclic aromatic hydrocarbon and tricyclic aromatic hydrocarbon⁺Aromatic hydrocarbons of 4 families (37 family boundary mixed standard solution two-dimensional profile is shown in the attached figure 2 of the specification, and the one-dimensional retention time and the two-dimensional retention time of each boundary substance are shown in the table 3).

TABLE 3 one-dimensional and two-dimensional retention time reference tables for boundary substances

2.3 Hydrocarbon identification and Classification of samples

The sample oil was subjected to test analysis on a GC x GC-FID (gas chromatography conditions are shown in table 1), and measured in parallel twice, and hydrocarbon identification and family classification of the compounds contained in the sample were performed using four divided groups (diesel oil full two-dimensional chromatogram profile (TIC chart) is shown in the attached fig. 1 of the specification).

Example two: quantitative analysis of polycyclic aromatic hydrocarbons in diesel

1 conditions of the apparatus

TABLE 1 typical all-two-dimensional gas chromatography conditions

2 quantitative analysis of samples

If the quantitative analysis adopts an external standard curve method, four groups of standard solutions with different concentrations are configured, a standard curve is drawn, and the peak area of each group is substituted into a formula (3) to calculate the content (mass fraction%) of each hydrocarbon. The polycyclic aromatic hydrocarbon content is calculated from the formula (5). And calculating the average value of the two parallel results to obtain the content of the polycyclic aromatic hydrocarbon in the diesel oil sample.

If the quantitative analysis adopts a peak area normalization method, the peak area of each group is substituted into the formula (4), and the content of each hydrocarbon is calculated. The polycyclic aromatic hydrocarbon content is calculated from the formula (5). And calculating the average value of the two parallel results to obtain the content of the polycyclic aromatic hydrocarbon in the diesel oil sample.

2.1 preparation of appearance Curve Standard solution

The standard substance (to the nearest 0.0001g) was weighed out in accordance with the concentration shown in Table 4, placed in a 100mL volumetric flask, and diluted to the mark with chromatographically pure hexane to prepare A, B, C, D four kinds of standard solutions.

TABLE 4 concentrations of standard solutions

2.2 drawing of working curves

After the gas phase operating conditions had stabilized (see Table 1), 1. mu.L of standard solution A, B, C, D was added. And recording the peak area of each standard substance of the two-dimensional map, and plotting the concentration g/100mL of each aromatic standard substance (n-undecane, p-xylene, 1-methylnaphthalene and phenanthrene) to the peak area, wherein the correlation coefficient is more than 0.999.

2.3 determination of the samples

The sample was directly transferred to a 1.5mL chromatographic vial and, if necessary, filtered to remove particulate matter from the sample. When the operating conditions were stable (see Table 1), 1. mu.L of the sample solution was subjected to test analysis on GC × GC-FID, and two-dimensional gas chromatography data was collected.

Note: some samples have aromatic concentration beyond the working curve range, and the samples are diluted by chromatographically pure hexane according to actual conditions.

2.4 calculation of

2.4.1 calculation of the content of the respective aromatic hydrocarbons

2.4.1.1 external standard curve method

Non-aromatic hydrocarbons, monocyclic aromatic hydrocarbons, bicyclic aromatic hydrocarbons and tricyclic aromatic hydrocarbons⁺The mass fraction of aromatic hydrocarbons is calculated according to formula (1):

ω_i＝[(A×S)+I]………………………………………(1)

in the formula:

ω_inon-aromatic, monocyclic, bicyclic and tricyclic aromatic hydrocarbons⁺Mass fraction of aromatic hydrocarbons, expressed in percentage;

a-non-aromatic or monocyclic or bicyclic or tricyclic aromatic hydrocarbons⁺Peak area of aromatic hydrocarbon;

s-non-aromatic or monocyclic aromatic or bicyclic aromatic or tricyclic⁺Slope of the operating curve for aromatics (% m/v vs. peak area);

i-non-aromatic or monocyclic aromatic or bicyclic aromatic or tricyclic⁺Intercept of the working curve of aromatics.

2.4.1.2 peak area normalization

Calculating non-aromatic hydrocarbon, monocyclic aromatic hydrocarbon, bicyclic aromatic hydrocarbon and tricyclic aromatic hydrocarbon according to formula (4)⁺Mass fraction of aromatic hydrocarbons ω_i[% (mass fraction)]：

In the formula:

ω_inon-aromatic, monocyclic, bicyclic and tricyclic aromatic hydrocarbons⁺Mass fraction of aromatic hydrocarbons, expressed in percentage;

A_inon-aromatic, monocyclic, bicyclic and tricyclic aromatic hydrocarbons⁺Peak area values of aromatic hydrocarbons;

∑A_i-sum of peak area values of the components.

Note: this calculation process may also be performed by the data processing system.

2.4.2 polycyclic aromatic hydrocarbons content.

Calculating the polycyclic aromatic hydrocarbon content omega by the formula (3)₁[% (mass fraction)]：

ω₁＝ω_{Bicyclic aromatic hydrocarbons}+ω_{Tricyclic + aromatic hydrocarbons}………………………………(3)

2.4.3 Total aromatics content.

The total aromatic content omega was calculated from the formula (4)₂[% (mass fraction)]：

ω₂＝ω_{Monocyclic aromatic hydrocarbon}+ω_{Bicyclic aromatic hydrocarbons}+ω_{Tricyclic + aromatic hydrocarbons}…………………………………(4)

2.4.4 Hydrocarbon content.

The sum of the contents of the hydrocarbons is used to obtain (non-aromatic hydrocarbon + monocyclic aromatic hydrocarbon + bicyclic aromatic hydrocarbon + tricyclic hydrocarbon)⁺Aromatic hydrocarbons).

Example three: investigation of detection methodology of polycyclic aromatic hydrocarbons in diesel by using full two-dimensional gas chromatography-hydrogen flame ionization detector (GC x GC-FID) 1

Three samples with different concentrations (mass fraction%) in high, low, medium and high are selected for testing and analyzing on GC x GC-FID, the determination is repeated for 7 times, the relative standard deviation is calculated, and the repeatability of the analysis method is inspected. The results are shown in Table 5. As can be seen from Table 5, the standard deviation of all 3 diesel oil samples measured by two-dimensional gas chromatography (GC X GC-FID) is within 5%. The two methods are proved to have good repeatability and meet the analysis requirement.

TABLE 5 relative standard deviation of polycyclic aromatic hydrocarbon content in diesel measured by two methods (n-7)

Example four: detection methodology investigation of polycyclic aromatic hydrocarbon in diesel oil by full two-dimensional gas chromatography-hydrogen flame ionization detector 2

In the experiment, a blank sample is selected at first, the content of polycyclic aromatic hydrocarbon in the blank sample is tested (the result of analyzing the content of PAH in the blank sample by different methods is different, the result measured by a peak volume normalization method is 4.3842%, and the result measured by an external standard method is 4.0091%), a known amount of polycyclic aromatic hydrocarbon standard substance is added and uniformly mixed, and three mixed standard solutions with different concentrations (total aromatic hydrocarbon is 4% -56%, polycyclic aromatic hydrocarbon is 0% -26%) are prepared. And (3) repeatedly measuring the sample for 7 times by adopting a GC x GC-FID analysis method, simultaneously selecting an external standard curve method and a peak area normalization method to carry out quantitative analysis on the test data, calculating the recovery rate of the added standard of the sample, and inspecting the accuracy of the analysis method. The results are shown in Table 6. As can be seen from Table 6, the normalized recovery of the diesel samples was between 90% and 110% as determined by two-dimensional gas chromatography (GC X GC-FID). The two methods are good in accuracy, and the accuracy meets the analysis requirement.

TABLE 6 measurement of polycyclic aromatic hydrocarbon recovery in diesel by two methods (n ═ 7)

Example five: 3, researching detection methodology of polycyclic aromatic hydrocarbon in diesel oil by using full two-dimensional gas chromatography-hydrogen flame ionization detector

10 diesel oil samples are selected for test analysis by adopting two methods of GC XGC-FID and the existing standard method SH/T0806-2008 respectively, wherein the GC XGC-FID quantitative analysis method selects a peak area normalization method and an external standard method, and the SH/T0806-2008 quantitative analysis method selects an external standard method. The results of the quantitative measurements of the two methods are compared and are shown in the attached figures 4 and 5 of the specification.

As can be seen from FIG. 4, for 10 diesel oil samples with different concentrations of polycyclic aromatic hydrocarbon, the results obtained by the two methods have good trend and consistency with the test results of the SH/T0806-2008 standard method. As can be seen in FIG. 5, the relative error of the test results of the area normalization method and the external standard method and the SH/T0806-2008 is within 5%. The analysis is integrated to obtain; the GC x GC-FID method has real and reliable data and is comparable with other standard methods.

Example six: investigation of detection methodology of polycyclic aromatic hydrocarbon in diesel oil by full two-dimensional gas chromatography-hydrogen flame ionization detector 4

The diesel oil fraction contains a small amount of oxygen-containing compounds, and the detection range of the SH/T0806-2008 standard method clearly indicates that the oxygen-containing compounds can influence the measurement result of the content of polycyclic aromatic hydrocarbons, and if the diesel oil contains fatty acid methyl ester, the content of tricyclic + aromatic hydrocarbons is higher. In consideration of the existence of the interferences, 22 representative oxygen-containing compounds and fatty acid methyl esters are added into a diesel base for test analysis, the results are shown in the attached figures 6 and 7 of the specification, and the experimental results show that the 22 oxygen-containing compounds and the fatty acid methyl esters are opposite to bicyclic aromatic hydrocarbons and tricyclic aromatic hydrocarbons⁺The qualitative and quantitative determination of the aromatic hydrocarbon does not have interference, but has influence on the qualitative and quantitative determination of the non-aromatic hydrocarbon and the monocyclic aromatic hydrocarbon. Compared with the analysis of the content of the polycyclic aromatic hydrocarbon in SH/T0806-2008, the method has better anti-interference performance and wider application range.

Example seven: diesel oil sample measurement 1

10 diesel oil samples are selected in the experiment, the GC X GC-FID (the chromatographic conditions are shown in the table 1) method is adopted for test analysis, and the peak area normalization method and the external standard curve method are selected as the quantitative analysis method.

(1) Preparation of standard curve standard solution

Appearance curves the standard solutions were prepared according to table 3, and the concentrations of the actual prepared standard solutions are shown in table 7.

TABLE 7 concentrations of actual preparation standard solutions

(2) Drawing of external standard curve

After the gas phase operation conditions had stabilized, 1. mu.L of standard solution A, B, C, D was added. And recording peak areas of all standard substances of the two-dimensional map, and plotting the concentration g/100mL of all aromatic standard substances (n-undecane, p-xylene, 1-methylnaphthalene and phenanthrene) to the peak areas, wherein the correlation coefficients are all larger than 0.999. The quantitative external standard curve of polycyclic aromatic hydrocarbon in diesel oil is shown in Table 8.

TABLE 8 quantitative standard curve of polycyclic aromatic hydrocarbon in diesel oil by external standard method

(3) Determination of samples

The sample was directly transferred to a 1.5mL chromatographic vial and, if necessary, filtered to remove particulate matter from the sample. When the operating conditions were stable (see Table 1), two-dimensional gas chromatography data was collected into 1. mu.L of sample solution.

(4) Quantitative external standard curve method

After the analysis is completed, the peak area of each group is substituted into the formula (3) to calculate the content of each hydrocarbon (mass fraction%). The polycyclic aromatic hydrocarbon content is calculated from the formula (5). And calculating the average value of the two parallel results to obtain the content of the polycyclic aromatic hydrocarbon in the diesel oil sample. The results are shown in Table 6.

Note: some samples have aromatic concentration beyond the working curve range, and the samples are diluted by chromatographically pure hexane according to actual conditions.

(5) Quantitative peak area normalization

After the analysis is completed, the peak area of each group is substituted into the formula (4), and the content of each hydrocarbon is calculated. The polycyclic aromatic hydrocarbon content is calculated from the formula (5). And calculating the average value of the two parallel results to obtain the content of the polycyclic aromatic hydrocarbon in the diesel oil sample. The results are shown in Table 9.

TABLE 910 analysis of diesel oil samples by different quantitative methods

Example eight: diesel oil sample measurement 2

In the experiment, diesel quality control samples provided by Qingdao Saishime science and technology Limited are selected and respectively tested and analyzed by adopting two methods of GC-FID and SH/T0806-2008, and a peak area normalization method and an external standard curve method are selected as quantitative analysis methods.

Standard Curve the standard solution configuration is shown in Table 2 and the quantitative standard curve in Table 3. After the analysis was completed, the peak areas of the respective groups were substituted into the formulas (3) and (4), and the content of each hydrocarbon (mass fraction%) was calculated by two quantitative methods. The polycyclic aromatic hydrocarbon content is calculated from the formula (5). And calculating the average value of the two parallel results to obtain the content of the polycyclic aromatic hydrocarbon in the diesel oil sample. And meanwhile, comparing the standard value with the standard value of the diesel quality control sample, and calculating the relative error. The results of the analysis of the two quantitative methods are shown in Table 10. The result shows that the relative error between the quantitative result of the diesel oil quality control sample and the standard value (PAH content: 3.49%) of the quality control sample is within 5%.

TABLE 10 control of diesel fuel quality by different methods PAH quantification and relative error (n is 3)