A method for determining the content of polyfluoroaniline and various related impurities

Abstract

The invention discloses a method for determining the content of polyfluoroaniline and various related impurities, and relates to the technical field of polyfluoroaniline analysis. The determination method comprises the following steps: preparing a gas chromatograph equipped with a high-precision automatic sample injector and an FID detector; preparing an improved chromatographic column with a specification of 30m×0.32mm×0.5μm; preparing a dilution solution acetonitrile and a control solution; accurately measuring polyfluoroaniline and impurity samples, adding a diluent acetonitrile to dissolve and dilute, and shaking well; injecting the sample solution for detection; deducting the blank, and reading the content of each substance by the area normalization method. The advantages of the present invention are: the present invention adopts a gas chromatography analysis method to separate polyfluoroaniline and various impurities, and the separation effect is good during the determination process, and more than 7 substances with similar structures can be easily separated, with good tolerance, stable detection results, and the characteristics of high accuracy and strong specificity; and the method has a short running time, which provides help for the design parameters of distillation and purification in production and improves the quality of polyfluoroaniline.

Description

Technical Field

[0001] The invention relates to the technical field of polyfluoroaniline analysis, and in particular to a method for determining the contents of polyfluoroaniline and multiple related impurities. Background Art

[0002] In the synthesis process of polyfluoroaniline, because it involves multi-step reactions such as hydrogenation, acylation, chlorination, addition, etc., the reaction conditions are harsh and complicated, so it is easier to produce some isomeric impurities and other by-products. Since the isomers and by-products have similar structures and similar properties, it is difficult to separate each substance well, and the separation effect is poor. It is difficult to measure the impurity content of polyfluoroaniline and the synthetic process. The present invention adopts gas chromatography, and cooperates with a chromatographic column with an improved stationary phase coating to separate polyfluoroaniline and various impurities, thereby reducing the difficulty of separation, improving the separation effect, and improving the accuracy of content determination. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a method for determining the content of polyfluoroaniline and various related impurities, which can solve the problems in the prior art that the separation of polyfluoroaniline and impurities generated during the synthesis process is difficult, the separation effect is poor, the determination of polyfluoroaniline and impurity contents is difficult, and the accuracy of the determination results is low.

[0004] In order to solve the above technical problems, the technical solution of the present invention is: comprising the following steps:

[0005] S1. Preparation of measurement conditions:

[0006] S1.1. Prepare a gas chromatograph equipped with a high-precision automatic sample injector and FID detector;

[0007] S1.2. Prepare a chromatographic column. The modified chromatographic column is a weak polar stationary phase, bonded and cross-linked with 5% diphenyl and 95% dimethyl polysiloxane. The chromatographic column specification is 30m×0.32mm×0.5μm;

[0008] S2. Solution preparation:

[0009] S2.1. Prepare dilution solution acetonitrile and control solution;

[0010] S2.2, sample solution: accurately measure 1.0g of polyfluoroaniline and impurity sample, accurately weigh, place in a 20mL volumetric flask, add 9.0g of diluent acetonitrile to dissolve and dilute, shake well;

[0011] S3, inject the sample solution for detection: the measurement conditions are: FID detector temperature 300°C, injection volume 0.2μL, split ratio 10:1, injection port temperature 250°C, carrier gas N2, carrier gas flow rate 2.5mL / min, hydrogen flow rate 40mL / min, air flow rate 450mL / min, and the chromatographic column is heated to 280°C;

[0012] S4. Subtract the blank and read the content of each substance using the area normalization method.

[0013] Furthermore, in the step S2.1, the control solution is prepared by taking 100 mg of each reference substance, accurately weighing it, placing it in a 20 mL weighing bottle, adding 10 g of diluent to dissolve it, and shaking it well; accurately weighing 0.5 g, 0.8 g, and 1.0 g of the above solution into three 20 mL weighing bottles, respectively, adding 9.5 g, 9.2 g, and 9.0 g of diluent to dissolve and dilute it, and shaking it well.

[0014] Furthermore, in step S2.2, the contents of seven impurities in the sample are determined simultaneously with polyfluoroaniline, and the structures and codes of the seven components are as follows:

[0015]

[0016]

[0017] Furthermore, in step S3, the temperature heating program of the chromatographic column is as follows: starting temperature 130°C, maintaining for 1.2 min; heating to 170°C at a heating rate of 5°C / min, maintaining for 3.5 min; heating to 185°C at a heating rate of 10°C / min; heating to 280°C at a heating rate of 30°C / min, maintaining for 1.2 min, and the total operating time is 18.7 min.

[0018] The advantages of the invention are as follows: the invention adopts a gas chromatography analysis method and cooperates with a chromatographic column with an improved stationary phase coating to separate polyfluoroaniline and various impurities, thereby reducing the difficulty of separation, being simple to operate, having a good separation effect during the determination process, being able to easily separate more than 7 substances with similar structures, having good tolerance, and having stable detection results. The accuracy of content determination (calculated by sample recovery rate) reaches more than 93.6%, and has the characteristics of high accuracy and strong specificity; and the method has a short running time, that is, the experimental results can be easily and quickly obtained, thereby effectively and quickly clarifying the impurity distribution, providing great help for the design parameters of distillation and purification in production, and improving the quality of polyfluoroaniline. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the test spectrum of the method in the present invention. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. The following embodiments can enable technicians in this field to understand the present invention more comprehensively, but the present invention is not limited to the scope of the embodiments.

[0021] This specific implementation method uses gas chromatography (GC) to determine the content of polyfluoroaniline and its related impurities, involving the separation of no less than 7 structurally similar substances. Specifically, an Agilent series gas chromatograph equipped with a FID detector and a high-precision automatic sampler is used, and a Finomei customized stationary phase coated chromatographic column is used to detect at least 7 substances.

[0022] The structure of polyfluoroaniline is shown below:

[0023] The impurity contents of 7 components in the sample were determined simultaneously with polyfluoroaniline. The structures and codes of the 7 components are as follows:

[0024]

[0025] Embodiment 1:

[0026] The following technical solution is adopted: comprising the following steps:

[0027] S1. Preparation of determination conditions: The chromatographic column is a Finomei chromatographic column, which is a modified chromatographic column with a weak polar stationary phase, bonded and cross-linked 5% diphenyl and 95% dimethylpolysiloxane, and the chromatographic column specification is 30m×0.32mm×0.5μm.

[0028] S2. Solution preparation:

[0029] S2.1. Prepare dilution solution acetonitrile and control solution;

[0030] S2.2, sample solution: accurately measure 1.0g of polyfluoroaniline and impurity sample, accurately weigh, place in a 20mL volumetric flask, add 9.0g of diluent acetonitrile to dissolve and dilute, shake well;

[0031] For the control solution, take 100 mg of each reference substance, accurately weigh it, place it in a 20 mL weighing bottle, add 10 g of diluent to dissolve, and shake well; accurately weigh 0.5 g, 0.8 g, and 1.0 g of the above solution in three 20 mL weighing bottles, respectively, add 9.5 g, 9.2 g, and 9.0 g of diluent in turn to dissolve and dilute, and shake well.

[0032] S3, inject the sample solution for detection: the measurement conditions are: FID detector temperature 300°C, injection volume 0.2 μL, split ratio 10:1, injection port temperature 250°C, carrier gas N2, carrier gas flow rate 2.5 mL / min, hydrogen flow rate 40 mL / min, air flow rate 450 mL / min;

[0033] The temperature program of the chromatographic column was as follows: starting temperature 130°C, maintained for 1.2 min; heating to 170°C at a heating rate of 5°C / min, maintained for 3.5 min; heating to 185°C at a heating rate of 10°C / min; heating to 280°C at a heating rate of 30°C / min, maintained for 1.2 min. The total operating time was 18.7 min.

[0034] S4. Subtract the blank and read the content of each substance using the area normalization method.

[0035] The test spectrum of the method in the present invention is shown in the attached Figure 1 , the separation effect is excellent.

[0036] Embodiment 2:

[0037] The accuracy of the method was investigated by adding impurities of different concentrations into the samples. The investigated concentrations were 0.25%, 0.5% and 0.75% of the sample concentration. Each concentration was repeated 3 times. The recoveries were all greater than 93.6%, and the relative standard deviation was ≤2.3%. The accuracy was calculated by measured value / true value × 100%.

[0038] Embodiment 3:

[0039] The tolerance of the test method was investigated by changing parameters such as carrier gas flow rate and heating rate. Only one parameter was changed in each test, and the parameter change range was ±10%. The results were compared with the results when the parameters were not changed. The retention time deviation of polyfluoroaniline and 7 related impurities was no more than 12.1%, the tailing factor was no more than 1.5, and the separation degree was no less than 1.5, which met the tolerance requirements of the method.

[0040] Comparative Example 1:

[0041] One chromatographic column each from different manufacturers (Agilent, Shimadzu, Waters) with similar specifications as those described in the present invention was prepared and tested under the same conditions as the custom-made Finomei chromatographic column: the separation degree of the impurities HPCFA and IHPCFA of the Agilent brand chromatographic column was less than 1.5, and the peaks of the impurities EALA and DCFAP of the Shimadzu brand chromatographic column and the Waters brand chromatographic column basically overlapped.

[0042] By adopting the analytical method of the above embodiment, the separation effect is better during the determination process, and more than 7 substances with similar structures can be easily separated, the tolerance is good, the detection results are stable, and the content determination accuracy of multiple substances (calculated by the sample recovery rate) reaches more than 93.6%, which has the characteristics of high accuracy and strong specificity; and when used in conjunction with a gas chromatograph equipped with a high-precision automatic sampler, the experimental results can be easily and quickly obtained, thereby effectively and quickly controlling the impurity distribution and improving product quality.

[0043] Due to the limitations of textual expression and the objective existence of many other similar chemical structures, ordinary technicians in this technical field can make appropriate improvements or changes without departing from the principles of the present invention, and can also combine the above-mentioned technical features in an appropriate manner; these improvements, changes or combinations, or the direct application of the inventive concept and technical solution to other occasions without improvement, should be regarded as the scope of protection of the present invention.

Claims

1. A method for determining the content of polyfluoroaniline and various related impurities, characterized in that: The following steps are involved: S1. Preparation of measurement conditions: S1.

1. Prepare a gas chromatograph equipped with a high-precision automatic sample injector and FID detector; S1.

2. Prepare a chromatographic column. The modified chromatographic column is a weak polar stationary phase, bonded and cross-linked with 5% diphenyl and 95% dimethyl polysiloxane, and the chromatographic column specifications are 30m×0.32mm×0.5μm; S2. Solution preparation: S2.

1. Prepare dilution solution acetonitrile and control solution; S2.2, sample solution: accurately measure 1.0g of polyfluoroaniline and impurity sample, accurately weigh, place in a 20mL volumetric flask, add 9.0g of diluent acetonitrile to dissolve and dilute, shake well; The contents of 7 impurities in the sample were determined simultaneously with polyfluoroaniline. The structures and codes of the 7 components are as follows: S3, inject the sample solution for detection: the measurement conditions are: FID detector temperature 300°C, injection volume 0.2μL, split ratio 10:1, injection port temperature 250°C, carrier gas N2, carrier gas flow rate 2.5mL / min, hydrogen flow rate 40mL / min, air flow rate 450mL / min, and the chromatographic column is heated to 280°C; The column temperature program was as follows: starting temperature 130°C, hold for 1.2 min; heating to 170°C at a heating rate of 5°C / min, hold for 3.5 min; heating to 185°C at a heating rate of 10°C / min; heating to 280°C at a heating rate of 30°C / min, hold for 1.2 min, with a total running time of 18.7 min; S4. Subtract the blank and read the content of each substance using the area normalization method.

2. The method for determining the content of polyfluoroaniline and various related impurities according to claim 1, characterized in that: In the step S2.1, the reference solution is prepared by accurately weighing 100 mg of each reference substance, placing it in a 20 mL weighing bottle, adding 10 g of diluent to dissolve, and shaking well; accurately weighing 0.5 g, 0.8 g, and 1.0 g of the above solution in three 20 mL weighing bottles, respectively, adding 9.5 g, 9.2 g, and 9.0 g of diluent in turn to dissolve and dilute, and shaking well.

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