阅读说明：本技术 一种7类精细化学品的定量分析方法 (Quantitative analysis method for 7-class fine chemicals ) 是由 张磊 刘俊霞 朱海林 于 2020-12-29 设计创作，主要内容包括：本发明公开一种7类精细化学品的定量分析方法,所述7类精细化学品包括四氢呋喃、乙醇、环己醇、环己酮、δ-戊内酯、γ-丁内酯和ε-己内酯,所述方法包含以下步骤：(1)7类精细化学品标准储备液的配制；(2)内标物标准储备液的配制,所述内标物为萘、苯和甲苯中的任意一种；(3)系列标准曲线溶液的配制；(4)色谱分析；(5)标准曲线的建立：以待测物和内标物的浓度之比为横坐标x,待测物和内标物的峰面积之比为纵坐标y,拟合得到标准曲线；(6)混合物的分析检测。所述方法操作简便、重复性好,分析误差小、精密度高,灵敏度好,能对样品中所有可测组分进行准确的定性定量分析。(The invention discloses a quantitative analysis method of 7 types of fine chemicals, wherein the 7 types of fine chemicals comprise tetrahydrofuran, ethanol, cyclohexanol, cyclohexanone, delta-valerolactone, gamma-butyrolactone and epsilon-caprolactone, and the method comprises the following steps: (1) preparing standard stock solutions of 7 types of fine chemicals; (2) preparing an internal standard stock solution, wherein the internal standard is any one of naphthalene, benzene and toluene; (3) preparing a series of standard curve solutions; (4) carrying out chromatographic analysis; (5) establishment of a standard curve: fitting to obtain a standard curve by taking the concentration ratio of the object to be measured and the internal standard substance as a horizontal coordinate x and the peak area ratio of the object to be measured and the internal standard substance as a vertical coordinate y; (6) and (4) analyzing and detecting the mixture. The method has the advantages of simple operation, good repeatability, small analysis error, high precision and good sensitivity, and can carry out accurate qualitative and quantitative analysis on all measurable components in the sample.)

1. A method for the quantitative analysis of fine chemicals of class 7, said fine chemicals of class 7 comprising tetrahydrofuran, ethanol, cyclohexanol, cyclohexanone, delta-valerolactone, gamma-butyrolactone and epsilon-caprolactone, characterized in that: the method comprises the following steps:

(1) preparing standard stock solutions of 7 types of fine chemicals: weighing tetrahydrofuran, ethanol, cyclohexanol, cyclohexanone, delta-valerolactone, gamma-butyrolactone and epsilon-caprolactone respectively, mixing, placing in a volumetric flask, and performing constant volume with an organic solvent to obtain standard stock solutions of 7 types of fine chemicals;

(2) preparing an internal standard stock solution: weighing an internal standard substance in a volumetric flask, and performing constant volume by using an organic solvent to obtain an internal standard substance standard stock solution; wherein the internal standard substance is any one of naphthalene, benzene and toluene;

(3) preparing a series of standard curve solutions: respectively mixing the 7 types of fine chemicals standard stock solution and the internal standard substance standard stock solution in a volumetric flask, and performing constant volume by using an organic solvent to obtain a mixed standard curve solution; respectively preparing at least 5 mixed standard curve solutions to form a series of standard curve solutions; in the series of standard curve solutions, the concentrations of the internal standard substances are the same, and the concentrations of the fine chemicals are different;

(4) and (3) chromatographic analysis: respectively carrying out gas chromatography analysis on the series of standard curve solutions, and recording peak areas;

(5) establishment of a standard curve: fitting to obtain a standard curve by taking the concentration ratio of the object to be measured and the internal standard substance as a horizontal coordinate x and the peak area ratio of the object to be measured and the internal standard substance as a vertical coordinate y, wherein the linear correlation coefficient R is greater than 0.9999;

(6) analysis and detection of the mixture: weighing a detection sample, placing the detection sample in a volumetric flask, adding an internal standard stock solution, and carrying out constant volume with an organic solvent to obtain a detection solution; filtering the detection solution by an organic filter membrane, performing gas chromatography, recording peak area, and calculating according to the standard curve to obtain the concentration of 7 types of fine chemicals in the detection sample; wherein the concentration of the internal standard substance in the detection solution is the same as the concentration of the internal standard substance in the series of standard curve solutions;

wherein the organic solvent is any one of methanol, acetonitrile and acetone.

2. The method for the quantitative analysis of a class 7 fine chemical according to claim 1, wherein: the conditions of the gas chromatographic analysis are as follows: the injection port temperature is 200-.

3. The method for the quantitative analysis of a class 7 fine chemical according to claim 2, wherein: in the standard stock solution of the 7 types of fine chemicals, the concentrations of tetrahydrofuran, ethanol, cyclohexanol, cyclohexanone, delta-valerolactone, gamma-butyrolactone and epsilon-caprolactone are the same and are 10-100 mg/mL.

4. The method for the quantitative analysis of a class 7 fine chemical according to claim 3, wherein: in the internal standard stock solution, the concentration of the internal standard substance is 10-100 mg/mL.

5. The method for the quantitative analysis of a class 7 fine chemical according to claim 4, wherein: in the series of standard curve solutions, the concentration of the 7 types of fine chemicals is 1.0-10 mg/mL.

6. The method for the quantitative analysis of a class 7 fine chemical according to claim 5, wherein: the concentration of the internal standard substance in the series of standard curve solutions is 1-5 mg/mL.

7. The method for the quantitative analysis of a class 7 fine chemical according to claim 6, wherein: the sampling range of the detection sample in the step (6) is 10-250 mg.

8. The method for the quantitative analysis of a class 7 fine chemical according to claim 7, wherein: the aperture of the organic filter membrane is 0.22 mu m.

Technical Field

The invention belongs to the technical field of chemical analysis, and particularly relates to a quantitative analysis method for 7 types of fine chemicals.

Background

Tetrahydrofuran, ethanol, cyclohexanol, cyclohexanone, delta-valerolactone, gamma-butyrolactone and epsilon-caprolactone are a series of common fine chemicals, and similar physical properties and chemical properties of the fine chemicals make the analysis and detection of the 7 compounds have great difficulty, so that a method for simultaneously detecting the tetrahydrofuran, the ethanol, the cyclohexanol, the cyclohexanone, the delta-valerolactone, the gamma-butyrolactone and the epsilon-caprolactone is developed, the effective separation and accurate quantification of the compounds are realized, and the method has important significance for the field of fine chemical engineering.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a quantitative analysis method of 7 types of fine chemicals, which is used for simultaneously detecting 7 types of fine chemicals such as tetrahydrofuran, ethanol, cyclohexanol, cyclohexanone, delta-valerolactone, gamma-butyrolactone and epsilon-caprolactone, and has the advantages of simple operation, small analysis error and high precision.

A method for the quantitative analysis of classes 7 fine chemicals, said classes 7 fine chemicals comprising tetrahydrofuran, ethanol, cyclohexanol, cyclohexanone, delta-valerolactone, gamma-butyrolactone and epsilon-caprolactone, said method comprising the steps of:

(1) preparing standard stock solutions of 7 types of fine chemicals: weighing tetrahydrofuran, ethanol, cyclohexanol, cyclohexanone, delta-valerolactone, gamma-butyrolactone and epsilon-caprolactone respectively, mixing, placing in a volumetric flask, and performing constant volume with an organic solvent to obtain standard stock solutions of 7 types of fine chemicals;

(2) preparing an internal standard stock solution: weighing an internal standard substance in a volumetric flask, and performing constant volume by using an organic solvent to obtain an internal standard substance standard stock solution; wherein the internal standard substance is any one of naphthalene, benzene and toluene;

(3) preparing a series of standard curve solutions: respectively mixing the 7 types of fine chemicals standard stock solution and the internal standard substance standard stock solution in a volumetric flask, and performing constant volume by using an organic solvent to obtain a mixed standard curve solution; respectively preparing at least 5 mixed standard curve solutions to form a series of standard curve solutions; in the series of standard curve solutions, the concentrations of the internal standard substances are the same, and the concentrations of the fine chemicals are different;

(4) and (3) chromatographic analysis: respectively carrying out gas chromatography analysis on the series of standard curve solutions, and recording peak areas;

(5) establishment of a standard curve: fitting to obtain a standard curve by taking the concentration ratio of the object to be measured and the internal standard substance as a horizontal coordinate x and the peak area ratio of the object to be measured and the internal standard substance as a vertical coordinate y, wherein the linear correlation coefficient R is greater than 0.9999; wherein the substance to be detected is tetrahydrofuran, ethanol, cyclohexanol, cyclohexanone, delta-valerolactone, gamma-butyrolactone and epsilon-caprolactone;

(6) analysis and detection of the mixture: weighing a detection sample, placing the detection sample in a volumetric flask, adding an internal standard stock solution, and carrying out constant volume with an organic solvent to obtain a detection solution; filtering the detection solution by an organic filter membrane, performing gas chromatography, recording peak areas, and calculating according to the standard curve to obtain the concentration of 7 types of fine chemicals in the mixture; wherein the concentration of the internal standard substance in the detection solution is the same as the concentration of the internal standard substance in the series of standard curve solutions;

wherein the organic solvent is any one of methanol, acetonitrile and acetone.

Preferably, the conditions of the gas chromatography are: the injection port temperature is 200-.

Preferably, the concentrations of tetrahydrofuran, ethanol, cyclohexanol, cyclohexanone, delta-valerolactone, gamma-butyrolactone and epsilon-caprolactone in the standard stock solution of the 7 types of fine chemicals are the same and are 10-100 mg/mL.

Preferably, the concentration of the internal standard in the internal standard stock solution is 10-100 mg/mL.

Preferably, the concentration of the class 7 fine chemical in the series of standard curve solutions is between 1.0 and 10 mg/mL.

Preferably, the concentration of the internal standard substance in the series of standard curve solutions is 1-5 mg/mL.

Preferably, the sampling range of the detection sample in the step (6) is 10-250 mg.

Preferably, the pore size of the organic filter membrane is 0.22 μm.

The reagents used in the invention are analytically pure, and the purity is more than 99%.

The purity of the high-purity nitrogen used by the gas chromatography analysis of the invention is more than 99.99 percent.

The standard stock solution of the 7 types of fine chemicals simultaneously contains tetrahydrofuran, ethanol, cyclohexanol, cyclohexanone, delta-valerolactone, gamma-butyrolactone and epsilon-caprolactone.

The invention has the advantages that:

the invention provides an analysis method capable of quantitatively and qualitatively analyzing 7 fine chemicals of tetrahydrofuran, ethanol, cyclohexanol, cyclohexanone, delta-valerolactone, gamma-butyrolactone and epsilon-caprolactone.

Drawings

FIG. 1 gas chromatogram.

Detailed Description

Example 1

A method for the quantitative analysis of classes 7 fine chemicals, said classes 7 fine chemicals comprising tetrahydrofuran, ethanol, cyclohexanol, cyclohexanone, delta-valerolactone, gamma-butyrolactone and epsilon-caprolactone, said method comprising the steps of:

(1) preparing standard stock solutions of 7 types of fine chemicals: weighing tetrahydrofuran, ethanol, cyclohexanol, cyclohexanone, delta-valerolactone, gamma-butyrolactone and epsilon-caprolactone respectively, mixing, placing in a volumetric flask, and performing constant volume with an organic solvent to obtain standard stock solutions of 7 types of fine chemicals;

(2) preparing an internal standard stock solution: weighing an internal standard substance in a volumetric flask, and performing constant volume by using an organic solvent to obtain an internal standard substance standard stock solution; wherein the internal standard substance is any one of naphthalene, benzene and toluene;

(3) preparing a series of standard curve solutions: respectively mixing the 7 types of fine chemicals standard stock solution and the internal standard substance standard stock solution in a volumetric flask, and performing constant volume by using an organic solvent to obtain a mixed standard curve solution; respectively preparing at least 5 mixed standard curve solutions to form a series of standard curve solutions; in the series of standard curve solutions, the concentrations of the internal standard substances are the same, and the concentrations of the fine chemicals are different;

(4) and (3) chromatographic analysis: respectively carrying out gas chromatography analysis on the series of standard curve solutions, and recording peak areas;

(5) establishment of a standard curve: fitting to obtain a standard curve by taking the concentration ratio of the object to be measured and the internal standard substance as a horizontal coordinate x and the peak area ratio of the object to be measured and the internal standard substance as a vertical coordinate y, wherein the linear correlation coefficient R is greater than 0.9999;

(6) analysis and detection of the mixture: weighing a detection sample, placing the detection sample in a volumetric flask, adding an internal standard stock solution, and carrying out constant volume with an organic solvent to obtain a detection solution; filtering the detection solution by an organic filter membrane, performing gas chromatography, recording peak areas, and calculating according to the standard curve to obtain the concentration of 7 types of fine chemicals in the mixture; wherein the concentration of the internal standard substance in the detection solution is the same as the concentration of the internal standard substance in the series of standard curve solutions;

wherein the organic solvent is any one of methanol, acetonitrile and acetone.

Preferably, the conditions of the gas chromatography are: the injection port temperature is 200-.

Example 2

On the basis of example 1, the concentrations of tetrahydrofuran, ethanol, cyclohexanol, cyclohexanone, delta-valerolactone, gamma-butyrolactone and epsilon-caprolactone in the standard stock solution of the 7 types of fine chemicals are the same and are 10-100 mg/mL;

in the internal standard stock solution, the concentration of the internal standard substance is 10-100 mg/mL;

in the series of standard curve solutions, the concentration of 7 types of fine chemicals is 1.0-10 mg/mL;

in the series of standard curve solutions, the concentration of the internal standard substance is 1-5 mg/mL;

the sampling range of the detection sample in the step (6) is 10-250 mg;

the aperture of the organic filter membrane is 0.22 mu m.

Example 3

A method for the quantitative analysis of classes 7 fine chemicals, said classes 7 fine chemicals comprising tetrahydrofuran, ethanol, cyclohexanol, cyclohexanone, delta-valerolactone, gamma-butyrolactone and epsilon-caprolactone, said method comprising the steps of:

(1) preparing standard stock solutions of 7 types of fine chemicals: weighing 1-10g of tetrahydrofuran, ethanol, cyclohexanol, cyclohexanone, delta-valerolactone, gamma-butyrolactone and epsilon-caprolactone respectively, mixing, placing in a 100mL volumetric flask, and performing constant volume with an organic solvent to obtain standard stock solutions of 7 types of fine chemicals;

(2) preparing an internal standard stock solution: weighing 1-10g of internal standard substance in a 100mL volumetric flask, and performing constant volume by using an organic solvent to obtain an internal standard substance standard stock solution; wherein the internal standard substance is any one of naphthalene, benzene and toluene;

(3) preparing a series of standard curve solutions: respectively mixing the 7 types of fine chemicals standard stock solution and the internal standard substance standard stock solution in a volumetric flask, and performing constant volume by using an organic solvent to obtain a mixed standard curve solution; respectively preparing at least 5 mixed standard curve solutions to form a series of standard curve solutions; in the series of standard curve solutions, the concentrations of the internal standard substances are the same, and the concentrations of the fine chemicals are different; the method comprises the following specific steps:

respectively taking 1-5mL of the 7-class fine chemical standard stock solution and 0.5-2mL of the internal standard stock solution, adding the solutions into a 15mL volumetric flask, fixing the volume by using an organic solvent, and shaking up for 1-2min to obtain a mixed standard curve solution 1; respectively taking 1-5mL of the 7-class fine chemical standard stock solution and 1-3mL of the internal standard stock solution, adding the solutions into a 20mL volumetric flask, fixing the volume by using an organic solvent, and shaking up for 1-2min to obtain a mixed standard curve solution 2; respectively taking 1-5mL of the 7-class fine chemical standard stock solution and 1.5-4mL of the internal standard stock solution, adding the solutions into a 30mL volumetric flask, fixing the volume by using an organic solvent, and shaking up for 1-2min to obtain a mixed standard curve solution 3; respectively taking 1-5mL of the 7-class fine chemical standard stock solution and 2-5mL of the internal standard stock solution, adding into a 50mL volumetric flask, carrying out constant volume on the organic solvent, and shaking up for 1-2min to obtain a mixed standard curve solution 4; respectively taking 1-5mL of the 7-class fine chemical standard stock solution and 5-10mL of the internal standard stock solution, adding the solutions into a 150mL volumetric flask, fixing the volume by using an organic solvent, and shaking up for 1-2min to obtain a mixed standard curve solution 5; obtaining 5 mixed standard curve solutions with different concentrations to form a series of standard curve solutions;

(4) and (3) chromatographic analysis: respectively carrying out gas chromatography analysis on the series of standard curve solutions, and recording peak areas; wherein, the gas chromatographic analysis conditions are as follows:

the used instruments are: a Sammer fly TRACE-1310 gas chromatograph;

a chromatographic column: one of TG-WAX, DB-1, HP-5;

column flow rate: 1.0-5.0 mL/min;

sample inlet temperature: 200 ℃ and 300 ℃;

a detector: hydrogen Flame Ionization Detector (FID), temperature: 200 ℃ and 300 ℃, air flow: 300-500 mL/min, hydrogen flow rate of 30-50 mL/min, tail gas blowing flow rate: 20-40mL/min

Column temperature: maintaining at 60-120 deg.C for 5-10min, heating to 200 deg.C at 5-25 deg.C/min, and maintaining for 10-20 min;

carrier gas: high-purity nitrogen (99.999%)

The split ratio is as follows: 10-100: 1;

sample introduction amount: 0.5-3.0 μ L;

(5) establishment of a standard curve: fitting to obtain a standard curve by taking the concentration ratio of the object to be measured and the internal standard substance as a horizontal coordinate x and the peak area ratio of the object to be measured and the internal standard substance as a vertical coordinate y, wherein the linear correlation coefficient R is greater than 0.9999; respectively obtaining a standard curve of tetrahydrofuran, a standard curve of ethanol, a standard curve of cyclohexanol, a standard curve of cyclohexanone, a standard curve of delta-valerolactone, a standard curve of gamma-butyrolactone and a standard curve of epsilon-caprolactone; wherein the substance to be detected is tetrahydrofuran, ethanol, cyclohexanol, cyclohexanone, delta-valerolactone, gamma-butyrolactone and epsilon-caprolactone;

(6) analysis and detection of the mixture: weighing 10-250mg of a detection sample, placing the detection sample in a 25mL volumetric flask, and adding 1-5mL of an internal standard stock solution; fixing the volume with organic solvent, and shaking for 1-2min to obtain detection solution; filtering the detection solution through an organic filter membrane with the aperture of 0.22 mu m, performing gas chromatography, recording peak area, and calculating according to the standard curve to obtain the concentration of 7 types of fine chemicals in the detection sample; wherein the concentration of the internal standard substance in the detection solution is the same as the concentration of the internal standard substance in the series of standard curve solutions;

wherein the organic solvent is any one of methanol, acetonitrile and acetone.

Example 4

A method for the quantitative analysis of classes 7 fine chemicals, said classes 7 fine chemicals comprising tetrahydrofuran, ethanol, cyclohexanol, cyclohexanone, delta-valerolactone, gamma-butyrolactone and epsilon-caprolactone, said method comprising the steps of:

(1) preparing standard stock solutions of 7 types of fine chemicals: weighing 5g of tetrahydrofuran, ethanol, cyclohexanol, cyclohexanone, delta-valerolactone, gamma-butyrolactone and epsilon-caprolactone respectively, mixing, placing in a 100mL volumetric flask, and performing constant volume with acetonitrile to obtain standard stock solutions of 7 types of fine chemicals; in the standard stock solution of the 7 types of fine chemicals, the concentrations of tetrahydrofuran, ethanol, cyclohexanol, cyclohexanone, delta-valerolactone, gamma-butyrolactone and epsilon-caprolactone are all 50 mg/mL;

(2) preparing an internal standard stock solution: taking naphthalene as an internal standard substance, weighing 2.0g of naphthalene into a 100mL volumetric flask, and carrying out constant volume with acetonitrile to obtain 20mg/mL internal standard substance standard stock solution;

(3) preparing a series of standard curve solutions: respectively mixing the 7 types of fine chemicals standard stock solution and the internal standard substance standard stock solution in a volumetric flask, and performing constant volume by using an organic solvent to obtain a mixed standard curve solution; respectively preparing at least 5 mixed standard curve solutions to form a series of standard curve solutions; in the series of standard curve solutions, the concentrations of the internal standard substances are the same, and the concentrations of the fine chemicals are different; the method comprises the following specific steps:

respectively taking 3mL of the 7-class fine chemical standard stock solution and 0.75mL of the internal standard stock solution, adding the solutions into a 15mL volumetric flask, carrying out constant volume on acetonitrile, and shaking up for 1-2min to obtain a mixed standard curve solution 1; respectively taking 3mL of the 7-class fine chemical standard stock solution and 1mL of the internal standard stock solution, adding the 7-class fine chemical standard stock solution and the internal standard stock solution into a 20mL volumetric flask, carrying out constant volume on acetonitrile, and shaking up for 1-2min to obtain a mixed standard curve solution 2; respectively taking 3mL of the 7-class fine chemical standard stock solution and 1.5mL of the internal standard stock solution, adding the 7-class fine chemical standard stock solution and the internal standard stock solution into a 30mL volumetric flask, carrying out constant volume on acetonitrile, and shaking up for 1-2min to obtain a mixed standard curve solution 3; respectively taking 3mL of the 7-class fine chemical standard stock solution and 2.5mL of the internal standard stock solution, adding the solutions into a 50mL volumetric flask, carrying out constant volume on acetonitrile, and shaking up for 1-2min to obtain a mixed standard curve solution 4; respectively taking 3mL of the 7-class fine chemical standard stock solution and 7.5mL of the internal standard stock solution, adding the solutions into a 150mL volumetric flask, carrying out constant volume on acetonitrile, and shaking up for 1-2min to obtain a mixed standard curve solution 5; obtaining 5 mixed standard curve solutions with different concentrations to form a series of standard curve solutions; the concentrations of the internal standard substances are all 1.0mg/mL, and the concentrations of tetrahydrofuran, ethanol, cyclohexanol, cyclohexanone, delta-valerolactone, gamma-butyrolactone and epsilon-caprolactone in the mixed standard curve solution 1 are all 10 mg/mL; in the mixed standard curve solution 2, the concentrations of tetrahydrofuran, ethanol, cyclohexanol, cyclohexanone, delta-valerolactone, gamma-butyrolactone and epsilon-caprolactone are all 7.5 mg/mL; in the mixed standard curve solution 3, the concentrations of tetrahydrofuran, ethanol, cyclohexanol, cyclohexanone, delta-valerolactone, gamma-butyrolactone and epsilon-caprolactone are all 5.0 mg/mL; in the mixed standard curve solution 4, the concentrations of tetrahydrofuran, ethanol, cyclohexanol, cyclohexanone, delta-valerolactone, gamma-butyrolactone and epsilon-caprolactone are all 3.0 mg/mL; in the mixed standard curve solution 5, the concentrations of tetrahydrofuran, ethanol, cyclohexanol, cyclohexanone, delta-valerolactone, gamma-butyrolactone and epsilon-caprolactone are all 1.0 mg/mL;

(4) and (3) chromatographic analysis: respectively carrying out gas chromatography analysis on the series of standard curve solutions, and recording peak areas; the chromatogram obtained is shown in FIG. 1, in which the abscissa represents time and the ordinate represents current; wherein, the gas chromatographic analysis conditions are as follows:

the used instruments are: a Sammer fly TRACE-1310 gas chromatograph;

a chromatographic column: a Saimer fly capillary column TG-WAX; specification of chromatographic column: 60 m.times.0.25 mm,1.0 μm (temperature range: -60-325/350 ℃);

column flow rate: 1.0 mL/min;

sample inlet temperature: 250 ℃;

a detector: hydrogen Flame Ionization Detector (FID), temperature: 250 ℃, air flow: 400 mL/min, hydrogen flow rate of 40mL/min, tail gas blowing flow rate: 35mL/min

Column temperature: heating at 60 deg.C for 10min, heating at 10 deg.C/min to 200 deg.C, and maintaining for 20 min;

carrier gas: high purity nitrogen (99.999%);

the split ratio is as follows: 80: 1;

sample introduction amount: 1 mu L of the solution;

(5) establishment of a standard curve: fitting to obtain a standard curve by taking the concentration ratio of the object to be measured and the internal standard substance as a horizontal coordinate x and the peak area ratio of the object to be measured and the internal standard substance as a vertical coordinate y, wherein the linear correlation coefficient R is greater than 0.9999; the standard curve for tetrahydrofuran is obtained: y =31.3596x-0.8823, R is 0.99994; the standard curve for ethanol is: y =47.6417x-0.3418, R is 0.99993; the standard curve for cyclohexanol is: y =51.4414x-0.4424, R is 0.99997; the standard curve for cyclohexanone is: y =51.074x-3.1125, R is 0.99998; the standard curve for delta valerolactone is: y =34.0046x-0.6470, R is 0.99993; the standard curve for gamma butyrolactone was: y =29.7039x-0.3524, R is 0.99991; the standard curve for epsilon-caprolactone is: y =39.1832x-1.5247, R is 0.99995; wherein the substance to be detected is tetrahydrofuran, ethanol, cyclohexanol, cyclohexanone, delta-valerolactone, gamma-butyrolactone and epsilon-caprolactone;

(6) analysis and detection of the mixture:

in the detection sample adopted in the embodiment, the theoretical content of each component is 0.15mg/mg of tetrahydrofuran, 0.12 mg/mg of ethanol, 0.10 mg/mg of cyclohexanol, 0.09 mg/mg of cyclohexanone, 0.20 mg/mg of delta-valerolactone, 0.15mg/mg of gamma-butyrolactone and 0.19 mg/mg of epsilon-caprolactone;

weighing 174mg of the detection sample, placing the detection sample in a 25mL volumetric flask, adding 1.25mL of internal standard stock solution, performing constant volume with acetonitrile, and shaking up for 1-2min to obtain a detection solution; the concentration of an internal standard substance in the detection solution is 1.0mg/mL, the detection solution is filtered by an organic filter membrane with the pore diameter of 0.22 μm, gas chromatography analysis is carried out, the peak area is recorded, and the content of each component in the detection solution can be obtained by calculation according to the standard curve: 1.023mg/mL of tetrahydrofuran, 0.854 mg/mL of ethanol, 0.586mg/mL of cyclohexanone, 0.682mg/mL of cyclohexanol, 1.125mg/mL of gamma-butyrolactone, 1.469mg/mL of delta-valerolactone and 1.327mg/mL of epsilon-caprolactone; and calculating to obtain the concentration of each component in the detection sample by conversion: tetrahydrofuran 0.147 mg/mg, ethanol 0.123 mg/mg, cyclohexanone 0.084 mg/mg, cyclohexanol 0.098 mg/mg, gamma-butyrolactone 0.162 mg/mg, delta-valerolactone 0.211 mg/mg, epsilon-caprolactone 0.191 mg/mg;

taking example 4 as an example, experiments were performed on precision, accuracy, detection limit, and quantification limit.

First, precision experiment

The detection solution of step (6) was taken, 2mL of the sample solution was collected by syringe, filtered, and injected into a sample injection vial for a total of 6 groups, numbered 1,2,3,4,5,6, and the results were measured by the above-mentioned chromatographic conditions and shown in table 1.

TABLE 1 results of precision experiments on test solutions

As can be seen from Table 1, the relative standard deviations of tetrahydrofuran, ethanol, cyclohexanol, cyclohexanone, delta-valerolactone, gamma-butyrolactone and epsilon-caprolactone in the measurement result are all less than 1.8%, which indicates that the detection method of the invention has good precision.

Second, accuracy experiment

Taking 2mL of the mixed standard curve solution 1 obtained in the step (3) of the example 4, and taking 4 groups in total; respectively placing the mixture into four 10mL volumetric flasks, respectively adding 100, 200 and 300 mu L of standard stock solution of the 7 types of fine chemicals into three volumetric flasks, respectively marking the stock solution as test solutions 1,2 and 3, and not adding the stock solution as a blank group, marking the stock solution as test solution 0, respectively and accurately adding 0.4mL of standard stock solution of an internal standard substance into the test solutions 0 to 3 to ensure that the concentration of the internal standard substance is 1.0mg/mL, fixing the volume to a scale by using an acetonitrile solvent, accurately sampling and analyzing by using a gas chromatograph, simultaneously recording peak areas, calculating the peak area ratio to obtain an actually measured additive amount, and calculating the additive recovery rate (see tables 2-8)

TABLE 2 experimental results on recovery of tetrahydrofuran by adding standard

TABLE 3 experimental results on recovery of ethanol with standard addition

TABLE 4 experimental results on the recovery of cyclohexanol by adding standard

TABLE 5 Cyclohexanone addition recovery Experimental results

TABLE 6 Delta-valerolactone recovery test results

TABLE 7 experimental results of gamma-butyrolactone standardized recovery

TABLE 8 results of recovery experiment using epsilon-caprolactone with standard addition

As can be seen from tables 2 to 8, the average recovery rates of the components are all more than 95%, and the method has high accuracy.

Third, detection and quantitation limits of the method

The detection limit of the method is calculated according to the ratio of the response value of the instrument to the noise being 3, and the quantification limit of the method is calculated according to the ratio of the response value of the instrument to the noise being 10.

Table 9 test results for detection limits and quantitation limits of the methods

It can be seen that the detection limit of each component of the reaction product is less than 0.5mg/L, the quantitative limit is less than 1.5mg/L, the sensitivity of the method is very high, and the analysis of trace components can be met.

According to the precision, the accuracy and the detection limit, the analysis method for measuring tetrahydrofuran, ethanol, cyclohexanol, cyclohexanone, delta-valerolactone, gamma-butyrolactone and epsilon-caprolactone by using the gas chromatography internal standard method is convenient and feasible, realizes effective separation and accurate quantification of 7 compounds, has high precision, good repeatability, high accuracy and simple and easy operation, can accurately perform qualitative and quantitative analysis on all measurable components in a mixture, does not need to perform any pretreatment on a sample except filtration, can realize direct and rapid detection on the sample, greatly shortens the analysis time, and has important significance for the field of fine chemical engineering.