A method for determining piperidine residues

Abstract

The invention discloses a method for determining piperidine residue, which comprises the following steps: the solvent is 1-5% ethylenediamine DMSO solution, the chromatographic column of the gas chromatograph is a CP-Volamine capillary column, the starting temperature is 75-85°C, maintained for 15 minutes, heated to 240°C at a rate of 30°C per minute, maintained for 10 minutes; injection port temperature: 215-225°C, detector FID temperature: 245-255°C, column flow rate: 1.8-2.2ml / min, split ratio 3:1. The present invention uses gas chromatography to determine the residual piperidine in the product with high separation efficiency, high recovery rate, fast analysis speed and high detection sensitivity, and can better control the piperidine residue in the product.

Description

Technical Field

[0001] The invention relates to the field of analytical technology, and in particular to a method for determining piperidine residues. Background Art

[0002] Piperidine is also known as hexahydropyridine, English name Piperidine, molecular formula: C5H 11 N is highly irritating and toxic to the human body. Small doses can stimulate the sympathetic and parasympathetic ganglia, while large doses have an inhibitory effect. If accidentally ingested, it can cause weakness, nausea, salivation, difficulty breathing, muscle paralysis and suffocation.

[0003] The main uses of piperidine are as solvent, organic synthesis intermediate, epoxy resin crosslinker, condensation catalyst, etc. It is also widely used in the pharmaceutical field and is an important raw material for products such as dipyridamole, cinacalcet, 3-fluoromethyllauric acid, etc. Therefore, it is extremely necessary to effectively control the residual amount of piperidine in the product and realize separation and detection. Summary of the invention

[0004] The purpose of the invention is to screen out a suitable solvent, explore a suitable pretreatment method, and establish a method for determining piperidine residues so as to better control the piperidine residues in the product.

[0005] The method for measuring piperidine residue of the present invention comprises the following steps:

[0006] Blank solvent: 1% ethylenediamine DMSO solution;

[0007] Test solution: accurately weigh about 1.0g of the sample to be tested, place it in a 10ml volumetric flask, add 1% ethylenediamine DMSO solution to dissolve it by ultrasonication and make up to the mark, shake well, and use this as the test solution;

[0008] Reference solution: accurately weigh an appropriate amount of piperidine, place it in corresponding volumetric bottles, dissolve it with 1% ethylenediamine DMSO solution and dilute it to make a solution containing 0.02 mg of piperidine per 1 ml, which is used as the reference solution;

[0009] Chromatographic column: CP-Volamine capillary column (30m×0.32mm×5μm)

[0010] Chromatographic conditions were as follows: starting temperature at 80°C, maintained for 15 min, heated to 240°C at a rate of 30°C per minute, maintained for 10 min; injection port temperature: 220°C, detector FID temperature: 250°C, column flow rate: 2.0 ml / min, split ratio 3:1;

[0011] Take 1 μl of the blank solvent, test solution, and reference solution respectively;

[0012] Calculate the linear regression equation between the concentration of the reference solution and the corresponding peak area value. The correlation coefficient should be no less than 0.99, and the peak shape of the reference solution should be symmetrical.

[0013] Depending on the pH value of the sample to be tested, the concentration of ethylamine DMSO solution can be adjusted between 1% and 5%. When the pH value is low, a higher concentration can be used, and when the pH value is high, a lower concentration can be used to achieve better results.

[0014] The invention uses gas chromatography to determine the residual piperidine in the product, has high separation efficiency, high recovery rate, fast analysis speed and high detection sensitivity, and can better control the residual piperidine in the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Screening chromatogram of the chromatographic column of Example 1

[0016] Figure 2 Screening chromatogram of Example 2 chromatographic column

[0017] Figure 3 Screening chromatogram of Example 3 chromatographic column

[0018] Figure 4 Example 4 Screening of chromatographic columns and solvents

[0019] Figure 5 Example 5 Screening Chromatogram of Solvent

[0020] Figure 6 Example 6 Screening Chromatogram of Solvent

[0021] Figure 7 Example 7 Screening Chromatogram of Solvent

[0022] Figure 8 Example 8 Screening Chromatogram of Solvent

[0023] Fig. 9 Example 9 Screening Chromatogram of Solvent

[0024] Fig.10 Example 10 Screening Chromatogram of Solvent

[0025] Fig.11 Example 11 Screening Chromatogram of Solvent

[0026] Fig.12 Example 12 Screening Chromatogram of Solvent

[0027] Fig.13 Optimization chromatogram of Example 13 solvent

[0028] Fig.14 Example 14 Optimization Chromatogram of Solvent

[0029] Fig.15 Chromatogram of separation test solution

[0030] Fig.16 Isopropyl alcohol linear regression plot

[0031] Fig.17 Linear regression plot of dichloromethane

[0032] Fig.18 Piperidine linear regression plot

[0033] Fig.19 Comparison chart of flow rate change test results

[0034] Fig. 20 Comparison chart of column temperature change test results

[0035] Fig.21 Comparison chart of detector temperature change test results

[0036] Fig. 22 Comparison chart of injector temperature change test results. Specific embodiments

[0037] The content of the present invention is further described in detail below by way of examples, but it should not be understood that the present invention is limited to the following examples within the scope of the above subject matter. Without departing from the above technical premise of the present invention, the corresponding replacement or modification made according to the common technical knowledge and customary means in the field are all included in the present invention.

[0038] Example 1 Screening of chromatographic columns

[0039] Instruments and reagents

[0040] Instruments: water bath, balance, gas chromatograph

[0041] Reagents: ethanol, pyridine, toluene, piperidine

[0042] Chromatographic column: TG-5MS, liquid injection, ethanol as solvent.

[0043] Column temperature: initially 80°C, maintained for 15 minutes, then increased to 240°C at a rate of 30°C per minute and maintained for 10 minutes.

[0044] Inlet temperature: 220°C, detector FID temperature: 250°C, column flow rate: 2.0 ml / min.

[0045] Results: Toluene and pyridine peaks have good shapes, but piperidine peak has severe tailing and partially overlaps with toluene peak, making it impossible to separate. The method is not applicable. Figure 1 .

[0046] Example 2 Screening of chromatographic columns

[0047] The chromatographic column is CD-BASEWAX, and other operations are the same as in Example 1.

[0048] Result: The peak shape of piperidine was poor and the response was very low. The method was not applicable. Figure 2 .

[0049] Example 3 Screening of chromatographic columns

[0050] Chromatographic column HP-5, other operations are the same as in Example 1.

[0051] Results: The peak shapes of toluene, pyridine and piperidine were good, but the elution time of piperidine and toluene partially overlapped, so the method was not applicable. Figure 3 .

[0052] Example 4 Screening of chromatographic columns and solvents

[0053] The chromatographic column was a CP-Volamine capillary column, and other operations were the same as in Example 1.

[0054] Results: The peak shape of the control solution was good and the separation degree met the requirements. However, when the dipyridamole, cinacalcet and 3-fluoromethyllauric acid samples were added with ethanol + 3% ammonia water as solvents and the standard solution containing pyridine, toluene and piperidine, the recovery rate of piperidine was determined to be 0, and the method was not applicable. Figure 4 .

[0055] Example 5 Screening of solvents

[0056] The reagents are ethanol + 0.2% ammonia water, pyridine, toluene, and piperidine. The other operations are the same as those in Example 4.

[0057] Results: Recovery solution, piperidine was not detected, the recovery rate did not meet the requirements, and the method was not applicable. Figure 5

[0058] Example 6 Screening of solvents

[0059] The reagents are ethanol + 3% ammonia water, pyridine, toluene, and piperidine. The other operations are the same as in Example 5.

[0060] Results: Recovery rate solution, piperidine can be detected, but the recovery rate does not meet the requirements, the method is not applicable. Figure 6 .

[0061] Example 7 Screening of solvents

[0062] The reagents are ethanol + 1% diethylamine, pyridine, toluene, and piperidine. The other operations are the same as in Example 5.

[0063] Results: Recovery solution, piperidine was not detected, the recovery rate did not meet the requirements, and the method was not applicable. Figure 7 .

[0064] Example 8 Screening of solvents

[0065] The reagents are ethanol + 10% diethylamine, pyridine, toluene, and piperidine. The other operations are the same as in Example 5.

[0066] Results: Recovery rate solution, detected more impurities, piperidine recovery rate of about 60%, the recovery rate does not meet the requirements, the method is not applicable. Figure 8 .

[0067] Example 9 Screening of solvents

[0068] The reagents are DMSO, pyridine, toluene and piperidine, and the other operations are the same as in Example 5.

[0069] Results: Recovery rate solution, piperidine recovery rate is about 70%, the recovery rate does not meet the requirements, the method is not applicable. Fig. 9 .

[0070] Example 10 Screening of solvents

[0071] The reagents are DMSO, sodium phosphate, sodium hydroxide, pyridine, toluene and piperidine. The other operations are the same as those in Example 5.

[0072] Results: When DMSO pH was adjusted with saturated sodium phosphate, sodium phosphate precipitated in DMSO, the separation between piperidine and toluene deteriorated, and the blank had interference, so the method was not applicable; using 0.1M sodium hydroxide as solvent and headspace injection, dipyridamole, cinacalcet, and 3-fluoromethyllauric acid samples were insoluble, so the method was not applicable; using 0.5M sodium hydroxide as solvent and headspace injection at 75℃ for 30min, the recovery rate of piperidine was 0, which did not meet the requirements, so the method was not applicable. Fig.10 .

[0073] Example 11 Screening of solvents

[0074] The reagents are ethylenediamine, pyridine, toluene and piperidine, and the other operations are the same as those in Example 5.

[0075] Results: The peak shape of the reference substance was good. When dipyridamole, cinacalcet, and 3-fluoromethyllauric acid samples were treated with ethylenediamine as solvent and piperidine was added, the recovery rate was over 95%, which met the requirements. However, ethylenediamine is highly corrosive and has a significant impact on the chromatographic column and detection equipment. The method needs to be optimized. Fig.11 .

[0076] Example 12 Screening of solvents

[0077] The reagents are 10% ethylenediamine DMSO solution, pyridine, toluene, and piperidine. The recovery rates of piperidine when 10%, 5%, and 1% ethylenediamine DMSO solution are used as solvent are screened respectively. Other operations are the same as those in Example 11.

[0078] Results: The peak shape of the reference substance was good. When dipyridamole, cinacalcet, and 3-fluoromethyllauric acid samples were treated with 10% ethylenediamine DMSO solution and piperidine was added, the recovery rate was above 95%, which met the requirements. Fig.12 .

[0079] Example 13 Optimization of solvent

[0080] The reagents are 5% ethylenediamine DMSO solution and piperidine, and the other operations are the same as Example 12.

[0081] Results: The recovery rate of piperidine was above 95%, and the recovery rate met the requirements. Fig.13 .

[0082] Example 14 Optimization of solvent

[0083] The reagents are 1% ethylenediamine DMSO solution and piperidine, and the other operations are the same as Example 13.

[0084] Results: The peak shape of the reference substance was good. Cinacalcet hydrochloride was used as the solvent for the sample with 1% ethylenediamine DMSO solution, and piperidine was added. The recovery rate was more than 95%, and the recovery rate met the requirements.

[0085] Conclusion: The samples can be dissolved using different proportions of ethylenediamine and DMSO as solvents, and the recovery rate of piperidine meets the requirements. In order to reduce the damage of ethylenediamine to the chromatographic column, it is better to use 1% ethylenediamine DMSO solution as solvent. Fig.14 .

[0086] Example 15 Establishment of detection method and system suitability test

[0087] Blank solvent: DMSO;

[0088] Test solution: accurately weigh about 1.0 g of cinacalcet, place in a 10 ml volumetric flask, add 1% ethylenediamine DMSO solution, ultrasonically dissolve and dilute to the mark, shake well, and use as the test solution;

[0089] Reference solution: dilute with 1% ethylenediamine DMSO solution to a 1 ml mixed solution containing about 2.0 mg of isopropanol, 2.0 mg of dichloromethane and 0.02 mg of piperidine as the reference solution;

[0090] Sample separation test solution: accurately weigh about 1.0g of cinacalcet, put it in a 10ml volumetric flask, accurately add 1ml of the control solution stock solution, add 1% ethylenediamine DMSO solution, ultrasonically dissolve and dilute to the scale, shake well, and use it as the sample separation test solution;

[0091] Positioning test solution: accurately measure 1 ml of isopropanol and dichloromethane reference substance stock solutions and place them in a 100 ml volumetric flask, accurately measure 1 ml of piperidine reference substance stock solution and place it in a 25 ml volumetric flask, and dilute to the mark with 1% ethylenediamine DMSO solution to serve as the respective solvent positioning solutions;

[0092] Chromatographic column: CP-Volamine capillary column (30m×0.32mm×5μm)

[0093] The chromatographic conditions were as follows: starting temperature was 80°C, maintained for 15 minutes, heated to 240°C at a rate of 30°C per minute, and maintained for 10 minutes; injection port temperature: 220°C, detector FID temperature: 250°C, column flow rate: 2.0 ml / min, split ratio 3:1.

[0094] Take 1 μl of each solution and record the chromatogram. Fig.15 The test results of the test sample plus reference solution are shown in Table 1, and the specificity test results are shown in Table 2.

[0095] Table 1 Precision test results

[0096]

[0097] Table 2 Specificity test results

[0098]

[0099] Results: There was no interference from the blank solvent; the resolution between each solvent was greater than 1.5; after 5 consecutive injections of isopropanol, the RSD of the peak area was 4.26%, and the RSD of the main peak retention time was 0.25%; after 5 consecutive injections of dichloromethane, the RSD of the peak area was 2.90%, and the RSD of the main peak retention time was 0.18%; after 5 consecutive injections of piperidine, the RSD of the peak area was 2.99%, and the RSD of the main peak retention time was 0.15%; the results showed that the method had good system applicability and specificity.

[0100] Example 16 Linearity and Range Test

[0101] Take appropriate amounts of isopropanol, dichloromethane and piperidine, weigh them accurately, add 1% ethylenediamine DMSO solution to dissolve and dilute to prepare reference stock solutions containing 100 mg of isopropanol, 100 mg of dichloromethane and 1.0 mg of piperidine per 1 ml, accurately measure 5 ml of each reference stock solution, place it in a 25 ml volumetric bottle, and dilute it with 1% ethylenediamine DMSO solution to a reference stock solution containing about 20 mg of isopropanol, 20 mg of dichloromethane and 0.2 mg of piperidine per 1 ml. Measure 1.0 ml, 1.0 ml, 2.0 ml, 1.0 ml, 3.0 ml and 2.0 ml of the reference stock solution, place them in 50 ml, 25 ml, 25 ml, 10 ml, 25 ml and 10 ml volumetric bottles respectively, add 1% ethylenediamine DMSO solution to dilute to the mark, shake well, and the solution is ready. 1 μl of sample was injected respectively, and the chromatogram was recorded, with the injection concentration (μg / ml) as the horizontal axis (x-axis) and the peak area as the vertical axis (y-axis). The results of the linear and range tests are shown in Tables 3, 4, 5 and Fig.16 , 17 、18.

[0102] Table 3 Isopropanol linearity and range test results

[0103]

[0104] Table 4 Dichloromethane linearity and range test results

[0105]

[0106] Table 5 Piperidine linearity and range test results

[0107]

[0108] The results showed that the linear equation of isopropanol was y=0.0333x+0.8072, and the peak area and concentration showed a good linear relationship in the range of 39.38138μg / ml to 3938.13800μg / ml. 2 =0.9995, the y-intercept deviation is 0.012; the linear equation of dichloromethane is y=0.0087x+0.0305, and the peak area and concentration show a good linear relationship in the range of 42.19376μg / ml to 4219.37640μg / ml, R 2 =0.9998, the y-intercept deviation is 0.002; the linear equation of piperidine is y=0.0453x–0.0338, and the peak area and concentration show a good linear relationship in the range of 4.15008μg / ml to 41.50080μg / ml, R 2 =0.9975, and the y-intercept deviation is -0.037.

[0109] Example 17 Detection Limit and Quantification Limit Test

[0110] The reference solution was diluted step by step, and the detection limit of each solvent was calculated with a signal-to-noise ratio S / N of not less than 3, and the quantification limit of each solvent was calculated with a signal-to-noise ratio S / N of not less than 10. The results are shown in Tables 6 and 7.

[0111] Table 6 Results of detection limit and quantification limit of each solvent to be tested

[0112]

[0113] Table 7 Results of quantitative limit precision test

[0114]

[0115] The results showed that the quantitative limit concentration of isopropanol was equivalent to 0.039% of the test sample concentration, and the RSD of the peak area for 5 consecutive injections was 8.83%; the quantitative limit concentration of dichloromethane was equivalent to 0.042% of the test sample concentration, and the RSD of the peak area for 5 consecutive injections was 8.53%; the quantitative limit concentration of piperidine was equivalent to 0.004% of the test sample concentration, and the RSD of the peak area for 5 consecutive injections was 9.89%; the quantitative limit under these chromatographic conditions met the requirements.

[0116] Example 18 Repeatability Test

[0117] Take 1.0g of this product, accurately weigh it, and place 6 parallel portions in 10ml volumetric bottles, add 1% ethylenediamine DMSO solution to dissolve it ultrasonically and dilute it to the mark as the test solution. Inject 1μl, and the results are shown in Table 1.3.2-8. The isopropanol content in the samples is 0.601%, the dichloromethane content is 0.353%, and piperidine is not detected; take 1.0g of this product, accurately weigh it, and place 6 parallel portions in 10ml volumetric bottles, accurately add 1ml of the control solution reserve solution, add 1% ethylenediamine DMSO solution to dissolve it ultrasonically and dilute it to the mark, shake well, and use it as the sample repeatability test solution. Inject 1μl, and the results are shown in Tables 8 and 9. The absolute deviation of the content in the sample repeatability test solution is less than 20% of the quality standard limit.

[0118] Table 8 Repeatability test results

[0119]

[0120] Table 9 Sample addition repeatability test results

[0121]

[0122] Conclusion: The same experimenter repeated the measurement of the same batch of samples 6 times, and the results showed that the number of solvent peaks above the quantitative limit was consistent. The detected contents of isopropanol and dichloromethane in the 6 test solutions were all 0.601%, 0.353%, and no piperidine was detected. The same experimenter repeated the measurement of the same batch of samples with the addition of control solution concentration 6 times, and the results showed that the number of solvent peaks above the quantitative limit was consistent. The absolute deviations of the contents in the 6 test solutions were all less than 20% of the quality standard limit. The RSD of the total solvent content (n=6) was 2.70%, which met the requirements, indicating that the method has good repeatability.

[0123] Example 19 Intermediate Precision Test

[0124] To investigate the influence of random variation factors on precision, different analysts, using different instruments on different days, analyzed the same batch under the repeatability test item to evaluate. Take 1.0g of this product, accurately weigh, and place 6 parallel portions in 10ml volumetric bottles, accurately add 1ml of control solution stock solution, add 1% ethylenediamine DMSO solution to ultrasonically dissolve and dilute to the scale, shake well, and make the intermediate precision test solution, inject 1μl, and the results are shown in Table 10.

[0125] Table 10 Precision test results

[0126]

[0127] The absolute deviations were all less than 20% of the quality standard limit, and the RSD (n=12) of the total solvent content was 3.82%, which met the requirements, indicating that the method had good precision.

[0128] Example 20 Recovery Test

[0129] Reference stock solution: Accurately weigh appropriate amounts of isopropanol, dichloromethane, and piperidine, place them in corresponding volumetric bottles, dissolve and dilute with 1% ethylenediamine DMSO solution to make a solution containing approximately 100 mg of isopropanol, 100 mg of dichloromethane, and 1 mg of piperidine per 1 ml, as the reference stock solution of each solvent. Accurately measure 5 ml of the reference stock solution of each solvent to a 25 ml volumetric flask, add 1% ethylenediamine DMSO solution to dilute to the scale, as the recovery stock solution. Accurately measure 1 ml of the recovery stock solution, place it in a 10 ml volumetric flask, and dilute with 1% ethylenediamine DMSO solution to a mixed solution containing approximately 2 mg of isopropanol, 2 mg of dichloromethane, and 0.02 mg of piperidine per 1 ml, as the reference solution.

[0130] Quantitative limit recovery stock solution: Take 1 ml of the reference stock solutions of isopropanol and dichloromethane, place them in 10 ml volumetric flasks respectively, dilute to the mark with 1% ethylenediamine DMSO solution, shake well, take 1 ml of the diluted isopropanol and 1 ml of dichloromethane, place them in a 10 ml volumetric flask, dilute to the mark with 1% ethylenediamine DMSO solution, shake well, and use them as the quantitative limit recovery stock solutions of isopropanol and dichloromethane respectively.

[0131] Solution with 80%, 100% and 120% recovery rate by adding sample: accurately weigh 2.5g, 1.0g and 2.5g of the product and place them in 25ml, 10ml and 25ml volumetric flasks respectively, add 1% ethylenediamine DMSO solution for ultrasonic dissolution, accurately measure 2ml, 1ml and 3ml of the above recovery rate stock solution and place them in 25ml, 10ml and 25ml volumetric flasks respectively, dilute to the scale with 1% ethylenediamine DMSO solution, shake well and use as solution with 80%, 100% and 120% recovery rate by adding sample.

[0132] Isopropanol and dichloromethane solution with quantitative limit concentration: accurately weigh 2.5 g of the product, place it in a 25 ml volumetric flask, add 1% ethylenediamine DMSO solution and ultrasonically dissolve it, add appropriate amount of isopropanol and dichloromethane quantitative limit recovery rate stock solution, make up to the scale with 1% ethylenediamine DMSO solution, shake well, and use this as the isopropanol and dichloromethane solution with quantitative limit concentration.

[0133] Piperidine sample quantitative limit concentration solution: accurately weigh 1.0 g of this product, put it in a 10 ml volumetric flask, add 1% ethylenediamine DMSO solution and ultrasonically dissolve it, add an appropriate amount of piperidine reference solution, dilute to the scale with 1% ethylenediamine DMSO solution, shake well, and use this as the piperidine sample quantitative limit concentration solution.

[0134] Three portions were prepared at each concentration level in the same manner, and the chromatographic conditions determined in Example 15 were used for determination. The recovery was calculated by the external standard method based on the peak area. The results are shown in Tables 11, 12, and 13.

[0135] Table 11 Isopropanol recovery test results

[0136]

[0137] Table 12 Dichloromethane recovery test results

[0138]

[0139] Table 13 piperidine recovery test results

[0140]

[0141] Conclusion: The average recoveries of isopropanol at the four concentration levels of quantification limit, low, medium and high were 100.37%, 95.96%, 96.47% and 94.61%, respectively, and the RSD of the four levels was 7.47%, less than 10.0%; the average recoveries of dichloromethane at the four concentration levels of quantification limit, low, medium and high were 88.10%, 100.71%, 100.86% and 99.26%, respectively, and the RSD of the four levels was 6.12%, less than 10.0%; the average recoveries of piperidine at the four concentration levels of quantification limit, low, medium and high were 88.14%, 100.20%, 95.86% and 94.38%, respectively, and the RSD of the four levels was 5.11%, less than 10.0%. The results showed that the method had good accuracy.

[0142] Example 21 Durability Test

[0143] Take the reference solution and 100% limit test solution and analyze them according to the following chromatographic conditions. The test results are shown in Fig.19 , 20 , 21, 22Tables 14, 15.

[0144] Table 14 Durability test results

[0145]

[0146] Table 15 Durability test

[0147]

[0148] Results and discussion: The injection port temperature varied in the range of 215℃~225℃, the flow rate varied in the range of 1.8ml / min~2.2ml / min, the detector temperature varied in the range of 245℃~255℃, the initial column temperature varied in the range of 75℃~85℃, the separation of each solvent in the control solution was greater than 1.5 (when the detector temperature was 255℃, the separation of isopropanol and adjacent impurity peaks was slightly worse but did not affect the quantification), the relative deviation of each solvent in the 100% limit test solution did not exceed 20% of the quality standard, indicating that the method has good durability.

[0149] Example 22 Cinacalcet Sample Determination

[0150] Take 3 batches of Cinacalcet samples, about 1.0g, weigh accurately, put into a 10ml volumetric flask, add 1% ethylenediamine DMSO solution to the scale, shake to dissolve, and obtain. According to the residual solvent determination method, take the test solution and the reference solution for injection, record the chromatogram, and calculate the residual amount of each solvent to be tested by the peak area according to the external standard method. The results are shown in Table 16.

[0151] Table 16 Determination results of each solvent to be tested

[0152]

[0153] Example 23 Determination of 3-fluoromethyllauric acid sample

[0154] Take 3 batches of 3-fluoromethyl lauric acid, about 1.0g, the structural formula of 3-fluoromethyl lauric acid is shown in Fig.16 , accurately weighed, placed in a 10ml volumetric flask, added 1% ethylenediamine DMSO solution to the scale, shaken to dissolve, and obtained. Example 15 Determination method, take the test solution and the reference solution for injection, record the chromatogram, and calculate the residual amount of each solvent to be tested by the peak area according to the external standard method. The results are shown in Table 17.

[0155] Table 17 Determination results of each solvent to be tested

[0156]

[0157] Example 24 Dipyridamole Sample Determination

[0158] Take 3 batches of dipyridamole, about 1.0g, weigh accurately, put into a 10ml volumetric flask, add 1% ethylenediamine DMSO solution to the scale, shake to dissolve, and obtain. According to the residual solvent determination method, take the test solution and the reference solution for injection, record the chromatogram, and calculate the residual amount of each solvent to be tested by the peak area according to the external standard method. The results are shown in Table 18.

[0159] Table 18 Determination results of each solvent to be tested

[0160]

Claims

1. A method for measuring piperidine residue, characterized in that It includes the following steps: Preparation of reference solution: accurately weigh an appropriate amount of piperidine, place it in a corresponding volumetric bottle, dissolve it in 1-5% ethylenediamine DMSO solution and dilute it to make a solution containing about 0.02 mg of piperidine per 1 ml, as the reference solution; Preparation of test solution: accurately weigh about 1.0g of the sample to be tested, place it in a 10ml volumetric flask, add 1-5% ethylenediamine DMSO solution to dissolve it by ultrasonication and make up to the scale, shake well, and use it as the test solution; Preparation of blank solution: 1-5% ethylenediamine DMSO solution; The chromatographic column is: CP-Volamine capillary column; Chromatographic conditions: starting temperature 75-85°C, maintained for 15 min, raised to 240°C at a rate of 30°C per minute, maintained for 10 min; Inlet temperature: 215-225°C, detector FID temperature: 245-255°C, column flow rate: 1.8-2.2 ml / min, split ratio 3:1; Injection: Take 1 μl of the blank solvent, test solution, and reference solution respectively, and record the chromatogram for liquid injection; calculate the piperidine residue by the external standard method.

2. the method for measuring piperidine residue as claimed in claim 1, is characterized in that: The concentration of ethylenediamine DMSO solution was 1%, and the chromatographic conditions included starting temperature: 80°C, injection port temperature: 220°C, detector FID temperature: 250°C, and column flow rate: 2.0 ml / min.

3. The method for the residual piperidines of claim 1, wherein: The concentration of ethylenediamine DMSO solution is 2%, and the chromatographic conditions include starting temperature: 75°C, injection port temperature: 215°C, detector FID temperature: 245°C, and column flow rate: 1.8 ml / min.

4. The method for measuring piperidine residue according to claim 1, wherein: The concentration of ethylenediamine DMSO solution is 5%, and the chromatographic conditions include starting temperature: 85°C, injection port temperature: 225°C, detector FID temperature: 255°C, and column flow rate: 2.2 ml / min.

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