CN113514566A

CN113514566A - Method for detecting potential residual solvent benzene in homopiperazine

Info

Publication number: CN113514566A
Application number: CN202010279301.8A
Authority: CN
Inventors: 陈云建; 杨建玲
Original assignee: KPC Pharmaceuticals Inc
Current assignee: KPC Pharmaceuticals Inc
Priority date: 2020-04-10
Filing date: 2020-04-10
Publication date: 2021-10-19

Abstract

The invention provides a method for detecting potential residual solvent benzene in homopiperazine, which comprises the following steps: a) mixing a sample to be detected with potassium carbonate, performing gas chromatography detection, and calculating according to a detection result and an established standard curve to obtain the content of potential residual solvent benzene in the homopiperazine; the stationary liquid of the chromatographic column for gas chromatography detection is 6% cyanopropylphenyl-94% dimethylpolysiloxane; the gas chromatography detection adopts a headspace sample injector, the equilibrium temperature of the headspace bottle is 80-90 ℃, and the equilibrium time of the headspace bottle is 20-40 min. Compared with the prior art, the detection method provided by the invention adopts optimized chromatographic conditions, and has good detection effect on benzene; the detection method has high accuracy, high sensitivity, high precision and high durability, and is suitable for detecting the potential residual solvent benzene in the high piperazine.

Description

Method for detecting potential residual solvent benzene in homopiperazine

Technical Field

The invention relates to the technical field of medicine quality control, in particular to a method for detecting potential residual solvent benzene in homopiperazine.

Background

Homopiperazine is a nitrogen-containing hetero seven-membered ring compound, is an important medical intermediate, is an important product starting from chemical industry and medical industry, and is widely applied to the fields of medicines, pesticides, surfactants, energetic materials and the like.

At present, the synthesis of homopiperazine takes ethylenediamine as a starting material, and is prepared by three steps of reactions of sulfonylation, cyclization and desulfonylation; however, the homopiperazine obtained by the above synthesis method may have a potential solvent benzene residue, which adversely affects the subsequent application of the homopiperazine, and therefore, the benzene residue needs to be detected and controlled in quality control.

Disclosure of Invention

In view of this, the present invention aims to provide a method for detecting benzene, a potential residual solvent in high piperazine, which has high accuracy, good sensitivity, good precision and good durability, and is suitable for detecting benzene, a potential residual solvent in high piperazine.

The invention provides a method for detecting potential residual solvent benzene in homopiperazine, which comprises the following steps:

a) mixing a sample to be detected with potassium carbonate, performing gas chromatography detection, and calculating according to a detection result and an established standard curve to obtain the content of potential residual solvent benzene in the homopiperazine;

the stationary liquid of the chromatographic column for gas chromatography detection is 6% cyanopropylphenyl-94% dimethylpolysiloxane;

the gas chromatography detection adopts a headspace sample injector, the equilibrium temperature of the headspace bottle is 80-90 ℃, and the equilibrium time of the headspace bottle is 20-40 min.

Preferably, the chromatographic column for gas chromatographic detection in the step a) is a capillary chromatographic column DB-624 UI.

Preferably, the column temperature conditions of the gas chromatography detection in the step a) are as follows:

the initial temperature is 30-50 deg.C, and is maintained for 10min, and the temperature is raised to 200 deg.C at the rate of 50 deg.C per minute, and is maintained for 10 min.

Preferably, the sample inlet temperature of the gas chromatography detection in the step a) is 140-160 ℃, and the split ratio is (4-6): 1.

preferably, the carrier gas for gas chromatography detection in step a) is nitrogen, the flow rate of the carrier gas is 2.8mL/min to 3.2mL/min, and the sample injection amount of the sample to be detected is 0.8mL to 1.2 mL.

Preferably, the chromatographic conditions of the headspace sampler in step a) further comprise:

the temperature of the sample injection ring is 85-95 ℃, and the temperature of the transmission pipe is 105-115 ℃;

the sample injection ring filling time is 0.01 min-0.03 min, and the sample injection ring balancing time is 0.4 min-0.6 min;

the pressurizing time is 25 s-35 s, and the sample injection time is 0.5 min-1.5 min;

the oscillation mode is high-speed oscillation, and the oscillation time is 0.5 min-1.5 min.

Preferably, the detector for gas chromatography detection in step a) is a hydrogen flame ionization detector, and the temperature of the detector is 190-210 ℃.

Preferably, before the gas chromatography detection in step a), the method further comprises:

pretreating the sample to be detected and potassium carbonate to obtain a sample solution; the pretreatment process specifically comprises the following steps:

and (3) taking the water solution of dimethyl sulfoxide with the volume fraction of 80% as a diluent to dissolve and dilute the high piperazine sample to be tested and potassium carbonate to obtain a test solution.

Preferably, the establishing of the standard curve in the step a) specifically includes the following steps:

a1) preparing a series of standard solutions with concentration, wherein the standard solutions are obtained by dissolving and diluting benzene and potassium carbonate by using a dimethyl sulfoxide aqueous solution with a volume fraction of 80% as a diluent;

a2) and respectively carrying out gas chromatography detection on the standard solutions with the series of concentrations, and establishing a standard curve according to the detection result and the concentration of benzene in the standard solutions with the series of concentrations.

Preferably, the concentration of the series of concentrations of the standard solution in the step a1) is 0.02 μ g/mL to 0.5 μ g/mL.

In addition, the invention adopts the optimized diluent, has no interference to the retention time of the benzene outgoing peak, and obviously reduces the mixed peak.

Drawings

FIG. 1 is a chromatogram of the diluent obtained in comparative example 1;

FIG. 2 is a chromatogram of a control solution obtained in comparative example 1;

FIG. 3 is a chromatogram of the diluent obtained in comparative example 2;

FIG. 4 is a chromatogram of a test solution of 100mg of sodium chloride obtained in comparative example 2;

FIG. 5 is a chromatogram of a test solution of 100mg of sodium sulfate obtained in comparative example 2;

FIG. 6 is a chromatogram of a test solution of 100mg of potassium carbonate obtained in comparative example 2;

FIG. 7 is a chromatogram of a test sample addition solution containing 100mg of benzene STD + sodium chloride obtained in comparative example 2;

FIG. 8 is a chromatogram of a test sample addition solution containing 100mg of benzene STD + sodium sulfate obtained in comparative example 2;

FIG. 9 is a chromatogram of a test sample addition solution containing 100mg of benzene STD + potassium carbonate obtained in comparative example 2;

FIG. 10 is a linear regression plot of the resulting benzene from the detection method provided in example 1;

FIG. 11 is a chromatogram of a detection limiting solution obtained by the detection method provided in example 1;

FIG. 12 is a chromatogram of a limiting quantitation solution obtained by the detection method provided in example 1;

FIG. 13 is a chromatogram of a blank solution obtained by the detection method provided in example 2;

FIG. 14 is a chromatogram of a benzene control solution obtained by the detection method provided in example 2;

FIG. 15 is a chromatogram of the proprietary solution obtained by the detection method provided in example 2;

FIG. 16 is a linear regression plot of benzene obtained by the detection method provided in example 2.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments of the present invention, and it should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

According to the invention, firstly, a sample to be detected and potassium carbonate are mixed and then subjected to gas chromatography detection, so as to obtain a detection result (chromatogram). In the invention, the sample to be detected is a homopiperazine sample to be detected; such potassium carbonates are inorganic salts well known to those skilled in the art. Before the gas chromatography detection, the method preferably further comprises the following steps:

and pretreating the sample to be detected and potassium carbonate to obtain a test solution. In the present invention, the pretreatment process preferably includes:

and (3) taking the water solution of dimethyl sulfoxide with the volume fraction of 80% as a diluent to dissolve and dilute the high piperazine sample to be tested and potassium carbonate to obtain a test solution. The invention selects the dimethyl sulfoxide aqueous solution with the volume fraction of 80% as the diluent, and has no interference to the retention time of the benzene peak, and the impurity peak is obviously reduced.

In a preferred embodiment of the present invention, the pretreatment process specifically comprises:

accurately weighing 100mg of potassium carbonate and 0.5g of homopiperazine, placing the potassium carbonate and the homopiperazine in a 20mL headspace bottle, adding 5mL of diluent to dissolve the potassium carbonate and the homopiperazine, and shaking up to obtain a test solution.

In the present invention, the gas chromatography detection is preferably measured according to the residual solvent measurement method (chinese pharmacopoeia 2015 edition four parts general rule 0861); the present invention is not particularly limited to the gas chromatography detection apparatus, and a gas chromatography detector known to those skilled in the art is used. In the invention, the stationary liquid of the chromatographic column for gas chromatography detection is 6% cyanopropylphenyl-94% dimethylpolysiloxane; the chromatographic column is preferably a capillary chromatographic column DB-624UI, and the specific specification is 30m multiplied by 320 mu m multiplied by 1.8 mu m.

In the present invention, the column temperature conditions for the gas chromatography detection are preferably:

the initial temperature is 30-50 ℃, the temperature is maintained for 10min, the temperature is raised to 200 ℃ at the rate of 50 ℃ per minute, and the temperature is maintained for 10 min;

more preferably:

the initial temperature was 40 deg.C for 10min, and the temperature was raised to 200 deg.C at a rate of 50 deg.C per minute for 10 min. The invention adopts the preferable column temperature condition, can improve the target peak, and leads the peak type to be better and the base line to be flatter.

In the invention, the gas chromatography detection sample inlet temperature is preferably 140-160 ℃, and more preferably 150 ℃; the gas chromatography detection split ratio is preferably (4-6): 1, more preferably 5: 1. aiming at the detection of potential residual solvent benzene in homopiperazine, the limitation of the injection port temperature and the split ratio has important influence on the improvement of a target peak, such as stable baseline and improvement of chromatographic peak separation degree.

In the invention, the carrier gas for gas chromatography detection is preferably nitrogen, and the flow rate of the carrier gas is preferably 2.8 mL/min-3.2 mL/min, and more preferably 3.0 mL/min; the sample volume of the sample to be detected by the gas chromatography is preferably 0.8 mL-1.2 mL, and more preferably 1.0 mL.

In the invention, a headspace sample injector is adopted for the gas chromatography detection, the equilibrium temperature of a headspace bottle is 80-90 ℃, preferably 85 ℃, and the equilibrium time of the headspace bottle is 20-40 min, preferably 30 min; the chromatographic conditions of the headspace sampler preferably further comprise:

the oscillation mode is high-speed oscillation, and the oscillation time is 0.5 min-1.5 min;

more preferably:

the temperature of the sample injection ring is 90 ℃, and the temperature of the transmission pipe is 110 ℃;

the sample injection ring filling time is 0.02min, and the sample injection ring balancing time is 0.5 min;

pressurizing for 30s, and sampling for 1 min;

the oscillation mode is high-speed oscillation, and the oscillation time is 1 min.

In the invention, the flow rate of the tail gas blowing gas detected by the gas chromatography is preferably 18 mL/min-22 mL/min, and more preferably 20 mL/min; the hydrogen flow rate detected by the gas chromatography is preferably 38 mL/min-42 mL/min, and more preferably 40 mL/min; the air flow rate detected by the gas chromatography is preferably 340mL/min to 360mL/min, and more preferably 350 mL/min.

In the present invention, the detector for gas chromatography detection is preferably a hydrogen Flame Ionization Detector (FID), and the detector temperature is preferably 190 ℃ to 210 ℃, more preferably 200 ℃.

In the invention, the change of the single chromatographic condition has a directional effect under the condition that the overall chromatographic condition is determined, but when the overall chromatographic condition is changed, the directional effect generated by the change of the same chromatographic condition can be changed and even opposite directional effect can be generated; therefore, the optimization of the chromatographic conditions is the result of the combined action of the chromatographic conditions which are mutually connected, and the independent decomposition of a certain chromatographic condition in the whole chromatographic conditions for evaluating the directional action has no significance. The detection method provided by the invention adopts optimized chromatographic conditions, and has good detection effect on benzene; the detection method has high accuracy, high sensitivity, high precision and high durability, and is suitable for detecting the potential residual solvent benzene in the high piperazine.

And after the detection result is obtained, calculating the content of the potential residual solvent benzene in the high piperazine according to the detection result and the established standard curve. In the present invention, the establishment of the standard curve preferably specifically includes the following steps:

The method comprises the steps of firstly preparing standard solutions with series concentrations, and dissolving and diluting benzene and potassium carbonate by using a dimethyl sulfoxide aqueous solution with a volume fraction of 80% as a diluent to obtain the standard solutions. In the present invention, the preparation method of the standard solution with the series of concentrations is preferably specifically:

accurately weighing 20mg of benzene, placing the weighed benzene into a 100mL measuring flask, adding a diluent to dissolve and dilute the benzene to a scale, shaking up the benzene, accurately weighing 1mL of benzene, placing the benzene into the 100mL measuring flask, adding the diluent to dissolve and dilute the benzene to the scale, and using the benzene as a benzene standard stock solution (2 mu g/mL);

further diluting the obtained benzene standard stock solution by adopting a diluent to obtain benzene standard solutions with series concentrations;

and finally, precisely weighing 100mg of potassium carbonate, placing the potassium carbonate into a 20mL headspace bottle, sucking 5mL of benzene standard solution with the series of concentrations, and rolling a cover to obtain the standard solution with the series of concentrations. The invention selects the dimethyl sulfoxide aqueous solution with the volume fraction of 80% as the diluent, and has no interference to the retention time of the benzene peak, and the impurity peak is obviously reduced.

In the present invention, the concentration of the standard solution of the series of concentrations is preferably 0.02. mu.g/mL-0.5. mu.g/mL, more preferably 0.02432. mu.g/mL-0.48640. mu.g/mL.

And then, respectively carrying out gas chromatography detection on the standard solutions with the series of concentrations, and establishing a standard curve according to the detection result and the concentration of benzene in the standard solutions with the series of concentrations. In the present invention, the gas chromatography detection is the same as that described in the above technical solution, and is not described herein again.

According to the invention, a standard curve is established through the relation between peak area and concentration in a detection result (chromatogram); the content of potential residual solvent benzene in the homopiperazine can be calculated according to the peak area of the corresponding benzene position in the detection result (chromatogram) of the sample to be detected; and, according to the product requirement, the content of residual benzene in the homopiperazine is not more than 2 ppm.

To further illustrate the present invention, the following examples are provided for illustration. The diluent used in the following examples and comparative examples of the present invention is an aqueous solution of dimethyl sulfoxide (DMSO) with a volume fraction of 80%, and the preparation method is as follows: precisely weighing 800mL of DMSO in a 1000mL volumetric flask, diluting with purified water to a scale, and shaking up to obtain the DMSO-based measuring instrument; the high piperazine test sample is obtained on the market; the solutions used in the following examples and comparative examples according to the invention were obtained according to the following formulation procedure:

standard stock solution (2. mu.g/mL): accurately weighing 20mg of benzene, placing the benzene in a 100mL measuring flask, adding a diluent to dissolve and dilute the benzene to a scale, accurately weighing 1mL of benzene, placing the benzene in the 100mL measuring flask, adding the diluent to dissolve and dilute the benzene to the scale, and shaking up the benzene to obtain the benzene.

Control solution (0.2. mu.g/mL): precisely transferring 10mL of the standard stock solution into a 100mL volumetric flask, diluting the standard stock solution to a scale with a diluent, and shaking up to obtain the stock solution; potassium carbonate 100mg was precisely weighed into a 20mL headspace bottle, and 5mL of the above control solution was aspirated, and the cap was rolled to serve as a standard solution to be tested (repeated 6 times).

Homopiperazine test solution: accurately weighing 100mg of potassium carbonate and 0.5g of homopiperazine sample into a 20mL headspace bottle, adding 5mL of diluent for dissolving, and shaking up to obtain the final product.

Comparative example 1

The measurement was carried out by a gas chromatograph according to the residual solvent measurement method (chinese pharmacopoeia 2015 edition four parts general rule 0861) under the following chromatographic conditions:

capillary chromatography column DB-624UI (30m × 0.32mm × 1.8 μm) was used; column temperature: the initial column temperature is 40 ℃, the temperature is maintained for 10min, the temperature is raised to 200 ℃ at the speed of 50 ℃/min, and the temperature is maintained for 10 min;

the temperature of a sample inlet is 150 ℃, the split ratio is 5: 1;

detector (FID) temperature is 200 ℃; the tail gas flow is 20mL/min, the hydrogen flow is 40mL/min, and the air flow is 350 mL/min;

the carrier gas is nitrogen, and the flow rate of the carrier gas is 3 mL/min;

the sample volume of the sample to be detected is 1 mL;

the headspace sampler chromatographic conditions were:

the furnace temperature is 80 ℃, the temperature of a sample injection ring is 90 ℃, the temperature of a transmission pipe is 110 ℃, the balance time of a small bottle is 30min, the sample injection ring sample filling time is 0.02min, the balance time of the sample injection ring is 0.5min, the pressurization time is 30s, the sample injection time is 1min, the oscillation mode is high-speed oscillation, and the oscillation time is 1 min;

chromatograms of the diluent and the control solution are respectively obtained and are shown in figures 1-2; wherein FIG. 1 is a chromatogram of the diluent obtained in comparative example 1, and FIG. 2 is a chromatogram of the control solution obtained in comparative example 1.

As can be seen from FIGS. 1-2, under the chromatographic conditions of comparative example 1, the retention time of benzene is 12.200min, and the diluent does not interfere with the benzene target peak; the chromatographic conditions were optimized to change the heater temperature to 90 c, taking into account the variation in the durable heater temperature.

Comparative example 2

(1) Solution preparation:

benzene STD (0.2. mu.g/mL): precisely transferring 5mL of the standard stock solution into a 50mL volumetric flask, diluting the standard stock solution to a scale with a diluent, and shaking up to obtain the product.

Test solution: respectively and precisely weighing 100mg of sodium chloride, 100mg of sodium sulfate and 100mg of potassium carbonate, respectively mixing with 0.5g of piperazine sample in a 20mL headspace bottle, sucking 5mL of diluent, rolling a cover, and shaking uniformly.

Adding a standard solution into a test sample: respectively and precisely weighing 100mg of sodium chloride, 100mg of sodium sulfate and 100mg of potassium carbonate, respectively mixing with 0.5g of piperazine sample in a 20mL headspace bottle, sucking 5mL of standard solution (0.2 mu g/mL), capping and shaking uniformly.

(2) The measurement was carried out by a gas chromatograph according to the residual solvent measurement method (chinese pharmacopoeia 2015 edition four parts general rule 0861) under the following chromatographic conditions:

the temperature of a sample inlet is 150 ℃, the split ratio is 5: 1;

the carrier gas is nitrogen, and the flow rate of the carrier gas is 3 mL/min;

the sample volume of the sample to be detected is 1 mL;

the headspace sampler chromatographic conditions were:

the furnace temperature is 90 ℃, the temperature of a sample injection ring is 90 ℃, the temperature of a transmission pipe is 110 ℃, the balance time of a small bottle is 30min, the sample injection ring sample filling time is 0.02min, the balance time of the sample injection ring is 0.5min, the pressurization time is 30s, the sample injection time is 1min, the oscillation mode is high-speed oscillation, and the oscillation time is 1 min;

chromatograms of the diluent, 100mg of sodium chloride, 100mg of sodium sulfate, 100mg of potassium carbonate, 100mg of benzene STD + sodium chloride, 100mg of benzene STD + sodium sulfate, and 100mg of benzene STD + potassium carbonate are obtained respectively and are shown in FIGS. 3-9; wherein, fig. 3 is a chromatogram of the diluent obtained in comparative example 2, fig. 4 is a chromatogram of a test solution of 100mg of sodium chloride obtained in comparative example 2, fig. 5 is a chromatogram of a test solution of 100mg of sodium sulfate obtained in comparative example 2, fig. 6 is a chromatogram of a test solution of 100mg of potassium carbonate obtained in comparative example 2, fig. 7 is a chromatogram of a test solution of 100mg of benzene STD + sodium chloride obtained in comparative example 2, fig. 8 is a chromatogram of a test solution of 100mg of benzene STD + sodium sulfate obtained in comparative example 2, and fig. 9 is a chromatogram of a test solution of 100mg of benzene STD + potassium carbonate obtained in comparative example 2.

The results are shown in Table 1.

TABLE 1 chromatographic results data for different solutions

Different inorganic salts	Retention time (min)	Peak area	Recovery (%)
				Diluent	/	/	/
Benzene STD	12.202	7.14859	/
				Diluent + sodium chloride	/	0	/
Benzene STD + sodium chloride 100mg	12.203	5.18716	72.56
				Diluent + sodium sulphate	/	0	/
Benzene STD + sodium sulfate 100mg	12.202	5.19221	72.63
				Diluent + potassium carbonate	/	0	/
Benzene STD + Potassium carbonate 100mg	12.202	5.13232	71.79

The result shows that the retention time and the peak area of the benzene are not obviously influenced by adding different inorganic salts, but the recovery rate measured under the chromatographic condition is not ideal, so that the chromatographic condition is optimized, and the temperature of a heater is changed to 85 ℃; on the basis, detection results of different inorganic salts are comprehensively considered, 100mg of potassium carbonate is selected, and further detection results are shown in table 2.

TABLE 285 ℃ chromatographic results data

The temperature of the heater is 85 DEG C	Retention time (min)	Peak area	Recovery (%)
				Diluent	/	/	/
Limit concentration of 80%	12.202	3.96039	/
				80% benzene limit concentration + test article	12.203	3.53220	89.27

As can be seen from Table 2, the recovery rate was significantly improved when the heater temperature was 85 ℃.

Example 1

(1) Solution preparation:

benzene Linear stock (2. mu.g/mL): 10mg of benzene is taken and placed in a 50mL measuring flask, a diluent is added to dissolve and dilute the benzene to the scale, then 1mL of benzene is precisely measured and placed in a 100mL measuring flask, and the diluent is added to dissolve and dilute the benzene to the scale to be used as a benzene standard stock solution (the benzene weighing amount is 12.16mg, and the concentration is 2.432 mu g/mL).

Benzene control solution (0.2. mu.g/mL): taking the benzene linear stock solution (2.432 mu g/mL), precisely measuring 5mL, placing in a 50mL measuring flask, adding a diluent to dissolve and dilute to a scale, precisely weighing 100mg of potassium carbonate, placing in a 20mL headspace flask, adding 5mL of the solution, capping, and shaking uniformly to obtain the final product.

Test solution: precisely weighing about 0.5g of a test sample and 100mg of potassium carbonate, placing the test sample and the 100mg of potassium carbonate into a 20mL headspace bottle, adding 5mL of diluent, rolling a cover, and shaking uniformly to obtain a test sample solution; the test sample is homopiperazine of different batches.

(2) Preparing a linear test solution according to the table 3, injecting the solution into an Agilent7890B gas chromatograph according to the chromatographic conditions of the table 4, recording a chromatogram, and performing linear regression analysis by taking the concentration as a horizontal coordinate and the peak area as a vertical coordinate to obtain a linear regression equation and obtain a linear correlation coefficient r, a slope and an intercept; the linearity results are shown in table 5 and fig. 10.

Table 3 benzene linearity test solution preparation data

Table 4 chromatographic conditions for the detection method provided in example 1

TABLE 5 benzene linearity results

The results show that the linear equation of benzene in the concentration range of 0.0243 mug/mL-0.48640 mug/mL is that y is 31.76591x +0.18036, the correlation coefficient r is 0.9999, the intercept is 0.18036, and the peak area is 10% of the peak area of the limit level which is less than 100%; therefore, benzene concentration in the range of 0.02432. mu.g/mL-0.48640. mu.g/mL was linearly related.

(3) And (3) sample determination:

the above-mentioned blank solvent, benzene reference solution and sample solution were measured precisely and 1mL each, and injected into a gas chromatograph, and the amount of benzene residual solvent in the sample was calculated by an external standard method, and the results are shown in Table 6.

TABLE 6 results of sample measurement

The results show that no benzene residue is detected in each batch of homopiperazine samples.

The quantitative limit and the detection limit of the detection method provided in example 1 were evaluated, specifically:

taking the 10% level (0.02. mu.g/mL) in the linear solution in Table 3, precisely weighing 100mg of potassium carbonate in a 20mL headspace bottle, sucking 5mL of the above solution, capping, measuring according to the chromatographic conditions in Table 4, with a signal-to-noise ratio of 9.3, which is defined as the detection limit solution, and the chromatogram is shown in FIG. 11.

Taking the 20% level (0.04. mu.g/mL) in the linear solution in Table 3, precisely weighing 100mg of potassium carbonate in a 20mL headspace bottle, sucking 5mL of the above solution, capping, measuring according to the chromatographic conditions in Table 4, the signal-to-noise ratio is 13.2, the solution is defined as the limit solution, and the chromatogram is shown in FIG. 12.

Example 2

(1) Preparing a solution:

diluent agent: accurately measuring DMSO 800mL in a 1000mL volumetric flask, diluting to a scale with purified water, shaking up, and marking as: a diluent.

Standard stock solution (2. mu.g/mL): accurately weighing 20mg of benzene, placing the benzene in a 100mL measuring flask, adding a diluent to dissolve and dilute the benzene to a scale, accurately weighing 1mL of benzene, placing the benzene in the 100mL measuring flask, adding the diluent to dissolve and dilute the benzene to the scale, and shaking up; the designations are: standard stock solutions.

Control solution (0.2. mu.g/mL): precisely transferring 10mL of standard stock solution into a 100mL volumetric flask, diluting the standard stock solution to a scale with a diluent, and shaking up; the designations are: a standard solution; accurately weighing 100mg of potassium carbonate in a 20mL headspace bottle, sucking 5mL of the solution, and rolling a cover; this solution was the standard solution to be tested (repeated 6 times).

Test solution: accurately weighing 100mg of potassium carbonate and 0.5g of homopiperazine sample in a 20mL headspace bottle, adding 5mL of diluent for dissolving, and shaking up; the designations are: a test solution.

(2) The determination method comprises the following steps: precisely measuring 1mL of the reference solution and 1mL of headspace gas of the sample, respectively, injecting into a gas chromatograph, and detecting according to the following chromatographic conditions:

the temperature of a sample inlet is 150 ℃, the split ratio is 5: 1;

the carrier gas is nitrogen, and the flow rate of the carrier gas is 3 mL/min;

the sample volume of the sample to be detected is 1 mL;

the headspace sampler chromatographic conditions were:

the furnace temperature (headspace bottle temperature) is 85 ℃, the sampling ring temperature is 90 ℃, the transmission pipe temperature is 110 ℃, the vial equilibrium time (headspace time) is 30min, the sampling ring filling time is 0.02min, the sampling ring equilibrium time is 0.5min, the pressurization time is 30s, the sampling time is 1min, the oscillation mode is high-speed oscillation, and the oscillation time is 1 min;

and calculating the amount of residual solvent benzene in the test sample according to an external standard method.

(3) System suitability test requirements and limits provision: (1) injecting a blank solvent (diluent) into a gas chromatograph, and recording a chromatogram; the blank solvent did not interfere at the benzene retention time. (2) Injecting the reference solution into a gas chromatograph, and recording a chromatogram; the RSD of the benzene peak area in the control solution of 6 consecutive needles is not more than 5%.

The specificity, system applicability, linearity and range, quantitative limit and detection line, accuracy, precision, solution stability and durability of the detection method provided in embodiment 2 are evaluated, specifically:

(1) the specificity is as follows:

blank solution: diluent (80% DMSO);

benzene control solution (0.2. mu.g/mL): placing 20mg of benzene in a 100mL measuring flask, adding a diluent to dissolve and dilute the benzene to a scale, precisely measuring 1mL of benzene, placing the benzene in the 100mL measuring flask, adding the diluent to dissolve and dilute the benzene to the scale, precisely measuring 5mL of benzene, placing the benzene in a 50mL measuring flask, adding the diluent to dissolve and dilute the benzene to the scale, precisely measuring 100mg of potassium carbonate, placing the potassium carbonate in a 20mL headspace flask, adding 5mL of the solution, rolling a cover, and shaking up to obtain the potassium carbonate.

A special solution: weighing about 0.5g of a test sample and 100mg of potassium carbonate, precisely weighing, placing in a 20mL headspace bottle, adding 5mL of diluent, rolling a cover, and shaking uniformly to obtain a special solution.

Respectively taking a benzene control solution, a blank solvent and a special solution, determining according to the detection method provided in the embodiment 2, and recording a chromatogram, wherein the result is shown in the following table 7, and the chromatogram is shown in fig. 13-15; fig. 13 is a chromatogram of a blank solution obtained by the detection method provided in example 2, fig. 14 is a chromatogram of a benzene control solution obtained by the detection method provided in example 2, and fig. 15 is a chromatogram of a specific solution obtained by the detection method provided in example 2.

TABLE 7 solvent positioning results

Name of solvent	Retention time (min)
		Benzene and its derivatives	12.206

The results show that no interfering peaks were found at the benzene retention time positions and that the blank solvent did not interfere with the assay. Therefore, the specificity of the method is good.

(2) The system applicability is as follows:

preparing a blank solvent: diluent (80% DMSO).

Control solution (0.2. mu.g/mL): placing 20mg of benzene in a 100mL measuring flask, adding a diluent to dissolve and dilute the benzene to a scale, shaking up, precisely transferring 1mL of benzene to the 100mL measuring flask, adding the diluent to dissolve and dilute the benzene to the scale, shaking up to serve as a reference stock solution, precisely measuring 5mL of the reference stock solution, placing the reference stock solution in a 50mL measuring flask, adding the diluent to dissolve and dilute the benzene to the scale, and shaking up; accurately weighing 100mg of potassium carbonate, placing the potassium carbonate in a 20mL headspace bottle, adding 5mL of reference solution, capping, and shaking up to obtain the potassium carbonate (repeating for 6 times).

Injecting the solution into a gas chromatograph, and recording a chromatogram; the results are shown in Table 8.

TABLE 8 results of benzene system suitability test

The results show that the blank solvent does not interfere at the benzene retention time; the RSD of the benzene peak area in the control solutions of 6 consecutive needles was 0.36%. Therefore, the system applicability of the method meets the requirement.

(3) Linearity and range:

linear stock (2. mu.g/mL): placing 20mg of benzene in a 100mL measuring flask, adding a diluent to dissolve and dilute to a scale, shaking up, precisely transferring 1mL of benzene in the 100mL measuring flask, adding the diluent to dissolve and dilute to the scale, and shaking up to obtain a linear stock solution.

Preparing linear test solutions according to the table 9, precisely weighing 100mg of potassium carbonate, placing the potassium carbonate in a 20mL headspace bottle, adding 5mL of each linear test solution, capping, shaking up, injecting into a chromatograph, recording a chromatogram, performing linear regression analysis by taking the concentration as a horizontal coordinate and the peak area as a vertical coordinate to obtain a linear regression equation, and obtaining a linear correlation coefficient r, a slope and an intercept; the results are shown in Table 10 and the linear regression plot is shown in FIG. 16.

TABLE 9 benzene Linear test solution preparation

TABLE 10 benzene linearity results

The results show that the linear equation of benzene in the concentration range of 0.02432 mug/mL-0.48640 mug/mL is 27.79827x +0.17330, the correlation coefficient r is 0.9997, the intercept is 0.17330, and the peak area is 10% of the peak area of the limit level of less than 100%.

And (4) conclusion: benzene concentration was well correlated linearly between 0.02432. mu.g/mL and 0.48640. mu.g/mL.

(4) Quantitative limit and detection line:

benzene limiting solution (0.08. mu.g/mL): precisely transferring the benzene stock solution into a 2.0-50 mL measuring flask, diluting the measuring flask to a scale with a diluent, shaking up, precisely weighing 100mg of potassium carbonate, placing the measuring flask in a 20mL headspace bottle, adding 5mL of the solution, rolling a cover, shaking up to obtain a benzene quantitative limit solution (repeating for 6 times).

Benzene detection limit solution (0.02. mu.g/mL): precisely transferring the benzene stock solution into a measuring flask of 1.0mL to 100mL, diluting the measuring flask to a scale with a diluent, shaking up, precisely weighing 100mg of potassium carbonate, placing the measuring flask in a 20mL headspace bottle, adding 5mL of the solution, rolling a cover, shaking up to obtain a benzene detection limiting solution (repeating for 6 times).

Injecting the solution into a gas chromatograph, and recording a chromatogram; the results are shown in Table 11.

TABLE 11 benzene quantitation limit and detection limit results

The result shows that the quantitative limit concentration of benzene in homopiperazine is 0.08 mu g/mL, which is equivalent to 40% of the limit concentration, the signal-to-noise ratio is more than 10, and the RSD% of the continuous 6-needle peak area is less than 10%; the detection limit concentration is 0.02 mu g/mL, which is equivalent to the level of 10% of the limit concentration, the signal-to-noise ratio is 3-10, and the RSD% of the continuous 6-needle peak area is less than 10%. Therefore, the sensitivity of the method is satisfactory.

(5) Accuracy:

control stock solution: linear stock solutions in the same (3) linear sum range;

80%, 100% and 120% limiting concentration control solutions: the same linear solution limits of 80%, 100% and 120% under item 7.3.

Adding a standard test solution at a limit concentration of 80%: precisely weighing 0.5g of high piperazine sample and 100mg of potassium carbonate, placing the high piperazine sample and the potassium carbonate in a 20mL headspace bottle, precisely transferring 5.0mL of 80% limit concentration reference solution, and shaking up; three portions were prepared in parallel.

Adding a standard test solution at a limit concentration of 100%: precisely weighing 0.5g of high piperazine sample and 100mg of potassium carbonate, placing the high piperazine sample and the potassium carbonate in a 20mL headspace bottle, precisely transferring 5.0mL of 100% limit concentration reference solution, and shaking up; three portions were prepared in parallel.

Adding a standard test solution at a limit concentration of 120%: precisely weighing 0.5g of high piperazine sample and 100mg of potassium carbonate, placing the high piperazine sample and the potassium carbonate in a 20mL headspace bottle, precisely transferring 5.0mL of 120% limit concentration reference substance solution, and shaking up; three portions were prepared in parallel.

Injecting the solution into a gas chromatograph according to requirements, recording a chromatogram, feeding three needles into each part, and calculating the recovery rate; the results are shown in Table 12.

TABLE 12 benzene accuracy test results

The result shows that the recovery rate of benzene is in the range of 87.97-98.13%; the average recovery of 9 solutions was 92.14% with an RSD of 4.46%. Therefore, the accuracy of the method is good.

(6) Precision:

6 parts of the 100% limit spiked sample solution were prepared as per the method in accuracy (5), and the benzene content and RSD% of the 6 parts were calculated and the results are shown in Table 13.

TABLE 13 examination of the Phenylarginine Density

The results showed that the average benzene content in 6 test samples added with the standard was 88.41% and the RSD was 0.81%.

Therefore, the method is excellent in precision.

(7) Solution stability:

blank solution: diluent (80% DMSO);

Adding a standard test solution: precisely weighing about 0.5g of a test sample and 100mg of potassium carbonate, placing the test sample and the potassium carbonate in a 20mL headspace bottle, adding 5mL of benzene reference solution, rolling a cover, and shaking up to obtain a standard added test sample solution.

And (3) sampling blanks and the solution at different times, recording a chromatogram, observing peak area change, comparing with the peak area of 0 hour, and calculating relative deviation, wherein the result is shown in the following table 14.

TABLE 14 benzene solution stability test results

The results show that the control solution and the standard sample solution are placed for 1 day at room temperature, and compared with the detection result at 0 hour, the maximum values of the relative deviation of the peak areas of the benzene control solution and the standard sample solution are respectively 4.50 percent and-6.52 percent. Therefore, the control solution and the standard sample solution are stable within 1 day at room temperature.

(8) Durability:

taking the blank solution, the reference solution and the added standard sample solution in the solution stability in the step (7), and detecting according to the chromatographic conditions of the detection method provided in the embodiment 2 to be used as the detection data of the initial conditions; the chromatographic conditions were slightly varied according to Table 15, the benzene contents in the control and test samples were measured, and the tolerance of the method was examined; the results are shown in Table 16 (stability 0 hours results as durability initial conditions).

TABLE 15 durability test

Parameter(s)	Initial conditions	Range of change
			Temperature at sample inlet	150℃	±10℃
Flow rate of carrier gas	3.0mL/min	±0.2mL/min
			Initial column temperature	40℃	±10℃
Amount of Potassium carbonate used	100mg	±20mg
			Equilibration time of headspace bottle	30min	±10min
Equilibrium temperature of headspace bottle	85℃	±5℃

TABLE 16 method durability test results

The results show that the blank solvent does not interfere with benzene measurements under each durability condition. The maximum relative deviation of the benzene content in the control solution and the maximum relative deviation of the benzene content in the spiked samples were-6.70% and-9.56%, respectively, as compared to the initial conditions. Therefore, under each durability condition, the blank solvent does not interfere with the measurement of homopiperazine benzene; the relative deviation of the benzene content is not more than 10% as compared with the initial condition, and the durability of the method is good.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for detecting potential residual solvent benzene in homopiperazine comprises the following steps:

2. The detection method according to claim 1, wherein the chromatographic column for gas chromatography detection in step a) is a capillary chromatographic column DB-624 UI.

3. The detection method according to claim 1, wherein the column temperature conditions of the gas chromatography detection in the step a) are as follows:

4. The detection method according to claim 1, wherein the sample inlet temperature of the gas chromatography detection in the step a) is 140-160 ℃, and the split ratio is (4-6): 1.

5. the detection method according to claim 1, wherein the carrier gas for gas chromatography detection in step a) is nitrogen, the flow rate of the carrier gas is 2.8mL/min to 3.2mL/min, and the sample volume of the sample to be detected is 0.8mL to 1.2 mL.

6. The detection method according to claim 1, wherein the chromatographic conditions of the headspace sampler in step a) further comprise:

7. The detection method according to claim 1, wherein the detector for gas chromatography detection in step a) is a hydrogen flame ionization detector, and the temperature of the detector is 190-210 ℃.

8. The detection method according to claim 1, wherein before the gas chromatography detection in step a), the method further comprises:

9. The detection method according to claim 1, wherein the establishment of the standard curve in step a) specifically comprises the following steps:

10. The detection method according to claim 9, wherein the concentration of the series of concentrations of the standard solution in step a1) is 0.02 μ g/mL to 0.5 μ g/mL.