Method for detecting cancerogen in sulfadoxine

Abstract

The invention relates to a method for detecting carcinogens in sulfadoxine. The method comprises the following steps: 1, preparing a blank solution and a test solution; 2, preparing a reference substance solution; and 3, taking the blank solution, the reference solution and the test solution, respectively carrying out gas chromatography determination in a gas chromatograph, recording a chromatogram, recording peak areas of trichloroethylene, aniline and N, N-dimethylaniline, and calculating the content of trichloroethylene, aniline and N, N-dimethylaniline in the sulfadoxine sample. By improving sulfadoxine pretreatment, limiting specific chromatographic conditions and accurately controlling detection conditions, the detection method disclosed by the invention is high in sensitivity, short in analysis time, high in specificity, relatively good in accuracy and precision and high in repeatability, and can meet sample detection requirements.

Description

Technical Field

[0001] This invention relates to the field of pharmaceutical testing and analysis technology, specifically to a method for detecting carcinogens in sulfadoxine. Background Technology

[0002] Sulfadoxin is a long-acting sulfonamide drug administered systemically, and is a broad-spectrum antibacterial agent. Its mechanism of action is similar to other sulfonamides; it competitively acts on dihydrofolate synthase in bacteria, preventing PABA from being used as a raw material to synthesize tetrahydrofolate, thus inhibiting bacterial protein synthesis and exerting its antibacterial effect. Sulfadoxin exhibits strong antibacterial activity against hemolytic streptococci, pneumococci, Shigella spp., Staphylococcus aureus, Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa, and Salmonella. In addition, sulfadoxine also has antimalarial activity.

[0003] Sulfadoxine, a commonly used active pharmaceutical ingredient (API), requires strict quality control for its safety. Trichloroethylene, aniline, and N,N-dimethylaniline, as potential impurities in this API, are under strict scrutiny due to their carcinogenicity: trichloroethylene is classified as a Group 1 carcinogen by the International Agency for Research on Cancer (IARC) of the World Health Organization, indicating it is carcinogenic to humans; aniline is classified as a Group 2B carcinogen (possibly carcinogenic to humans); and N,N-dimethylaniline is classified as a Group 3 carcinogen (its carcinogenicity to humans is not yet established, but requires careful control). Currently, there are no publicly available studies or analytical methods for detecting trichloroethylene, aniline, and N,N-dimethylaniline in sulfadoxine API. Therefore, establishing accurate and reliable detection methods is crucial for ensuring the quality of sulfadoxine API. In the existing technology, the analysis of trichloroethylene, aniline and N,N-dimethylaniline in sulfadoxine raw material faces the following difficulties: direct injection of the sample after dissolution or headspace injection matrix interference, low recovery rate, difficulty in separating the three components at the same time, and low sensitivity. Summary of the Invention

[0004] To address the aforementioned technical problems, the present invention aims to provide a method for detecting carcinogens in sulfadoxine. This invention improves the sulfadoxine pretreatment process, defines specific chromatographic conditions, and precisely controls the detection conditions, providing a highly efficient and reliable GC chromatographic analysis method. This solves the problems of insufficient resolution, sensitivity, and matrix interference in the detection of Group 3 carcinogens in sulfadoxine raw materials using existing technologies.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: The first objective of this invention is to provide a method for detecting carcinogens in sulfadoxine, the method comprising the following steps: (1) Dissolve the sulfadoxine sample in sodium hydroxide solution, then add diluent and sodium chloride in sequence, let stand, and take the lower layer as the test solution for later use; add sodium hydroxide solution and sodium chloride in sequence to the diluent, let stand, and take the lower layer as the blank solution for later use. (2) Weigh trichloroethylene, aniline, N,N-dimethylaniline, and dissolve them in cyclohexane to prepare reference stock solution ①. Dilute the reference stock solution ① with cyclohexane to prepare reference stock solution ②. Dilute the reference stock solution ② with dichloromethane to prepare reference stock solution ③. Add sodium hydroxide solution and sodium chloride solution to the reference stock solution ③ in sequence, mix and let stand, and take the lower layer as the reference solution. (3) Inject the blank solution, reference solution, and test solution into the gas chromatograph and record the chromatograms; calculate the contents of trichloroethylene, aniline, and N,N-dimethylaniline in the sulfadoxine sample; The formula for the calculation is: ; Wherein, A 供试品 The peak area of ​​trichloroethylene / aniline / N,N-dimethylaniline in the test solution; The A 对照品 The average peak area of ​​the reference solution is trichloroethylene / aniline / N,N-dimethylaniline. The g 供试品 Weigh the sample for testing; The g 对照品 The sample weight of the reference solution trichloroethylene / aniline / N,N-dimethylaniline; Furthermore, record the peak areas and total peak areas of trichloroethylene, aniline, and N,N-dimethylaniline in the test solution, and then calculate the contents of trichloroethylene, aniline, and N,N-dimethylaniline in the sulfadoxine sample according to the formula.

[0006] The beneficial effects of this invention are: by improving the pretreatment of sulfadoxine, limiting specific chromatographic conditions, and precisely controlling the detection conditions, the detection method of this invention has high sensitivity, short analysis time, strong specificity, good accuracy and precision, and strong repeatability, which can meet the sample detection requirements.

[0007] Furthermore, the diluent includes cyclohexane and dichloromethane, wherein the volume ratio of cyclohexane to dichloromethane is 5:95.

[0008] The beneficial effects of adopting the above-mentioned further scheme are: sulfadoxine is almost insoluble in water but readily soluble in sodium hydroxide solution. By dissolving sulfadoxine in sodium hydroxide solution, adding cyclohexane-dichloromethane diluent, and then extracting the target analyte by sodium chloride salting-out, the sample matrix interference is effectively removed, improving the extraction efficiency and detection accuracy of the target analyte.

[0009] Based on the above technical solution, the present invention can be further improved as follows.

[0010] Furthermore, the chromatographic column used for detection in step (3) is a medium polar capillary column with a specification of 30m*0.53mm*3.0μm, and the stationary phase is 6% cyanopropylphenyl / 94% dimethylpolysiloxane.

[0011] Furthermore, the chromatographic column of the present invention is an Agilent DB-624 (30m×0.53mm×3.0μm), a Phenomen ZB-624 (30m×0.53mm×3.0μm) or a column with equivalent performance.

[0012] The beneficial effects of adopting the above-mentioned further scheme are: by screening specific medium polar chromatographic columns, the 6% cyanopropylphenyl / 94% dimethyl polysiloxane stationary phase can significantly improve the separation performance of the analytes. Compared with the DB-FFAP polar chromatographic column, this method has higher separation degree for components with large polarity differences such as trichloroethylene and aniline, more symmetrical peak shape, reduced co-elution interference, and optimized and improved separation efficiency.

[0013] Furthermore, in the reference solution, the concentration of trichloroethylene is 53.25 μg / ml to 53.34 μg / ml, the concentration of aniline is 47.5 μg / ml to 48.4 μg / ml, and the concentration of N,N-dimethylaniline is 8.25 μg / ml to 8.34 μg / ml.

[0014] Furthermore, in the reference stock solution ①, the concentration of trichloroethylene is 26.63 μg / ml to 26.67 mg / ml, the concentration of aniline is 23.75 μg / ml to 24.20 mg / ml, and the concentration of N,N-dimethylaniline is 4.13 μg / ml to 4.17 mg / ml; In the reference stock solution ②, the concentration of trichloroethylene is 1065.0 μg / ml to 1066.8 μg / ml, the concentration of aniline is 950 μg / ml to 968 μg / ml, and the concentration of N,N-dimethylaniline is 165.0 μg / ml to 166.8 μg / ml; In the reference stock solution ③, the concentration of trichloroethylene is 53.25~53.34 μg / ml, the concentration of aniline is 47.5 μg / ml~48.4 μg / ml, and the concentration of N,N-dimethylaniline is 8.25 μg / ml~8.34 μg / ml.

[0015] The beneficial effect of adopting the above-mentioned further scheme is that dichloromethane is too volatile, and the balance cannot be stabilized when it is directly used as a solvent for weighing the reference standard. Using cyclohexane as the first step solvent can significantly improve the accuracy of the reference standard weighing.

[0016] Furthermore, in step (3), the carrier gas used for detection is nitrogen, the injection port split ratio is 3:1, and the flow rate of the chromatographic column is 4.5 mL / min to 5.5 mL / min.

[0017] The beneficial effects of adopting the above-mentioned further scheme are as follows: trichloroethylene is non-polar with a boiling point of 87.2℃, aniline is moderately polar with a boiling point of 196℃, and N,N-dimethylaniline is moderately polar with a boiling point of 193℃. This invention uses a moderately polar chromatographic column, sets specific chromatographic conditions, and combines precise column temperature programs, flow rates, and other parameters to achieve efficient separation of trichloroethylene, aniline, and N,N-dimethylaniline (resolution ≥ 1.5, theoretical plate number ≥ 5000), laying the foundation for accurate determination.

[0018] Furthermore, the injection volume during the detection in step (3) is 1 μL.

[0019] The beneficial effects of adopting the above-mentioned further scheme are as follows: trichloroethylene is non-polar with a boiling point of 87.2℃, aniline is moderately polar with a boiling point of 196℃, and N,N-dimethylaniline is moderately polar with a boiling point of 193℃. This invention uses a moderately polar chromatographic column, sets specific chromatographic conditions, and combines precise column temperature programs, flow rates, and other parameters to achieve efficient separation of trichloroethylene, aniline, and N,N-dimethylaniline (resolution ≥ 1.5, theoretical plate number ≥ 5000), laying the foundation for accurate determination.

[0020] Furthermore, in step (3), the hydrogen flow rate during detection is 30 mL / min, the air flow rate is 300 mL / min, and the supplementary gas is nitrogen with a flow rate of 25 mL / min.

[0021] The beneficial effects of adopting the above-mentioned further scheme are as follows: trichloroethylene is non-polar with a boiling point of 87.2℃, aniline is moderately polar with a boiling point of 196℃, and N,N-dimethylaniline is moderately polar with a boiling point of 193℃. This invention uses a moderately polar chromatographic column, sets specific chromatographic conditions, and combines precise column temperature programs, flow rates, and other parameters to achieve efficient separation of trichloroethylene, aniline, and N,N-dimethylaniline (resolution ≥ 1.5, theoretical plate number ≥ 5000), laying the foundation for accurate determination.

[0022] Furthermore, in step (3), the temperature of the vaporization chamber during detection is 250℃ and the temperature of the detector is 280℃; the column chamber adopts programmed temperature rise, with an initial column temperature of 48℃~52℃, the initial column temperature held for 1 min, a heating rate of 13~17℃ / min, a final column temperature of 220℃, and a final column temperature held for 6 min.

[0023] The beneficial effects of adopting the above-mentioned further scheme are: the present invention can accurately control the detection conditions, and use a flame ionization detector in conjunction with programmed temperature rise and split injection to achieve rapid analysis at a carrier gas flow rate of 5.0 mL / min (total running time ≤20 minutes), while avoiding column overload.

[0024] Furthermore, the injection sequence in step (3) is blank solution, reference solution, blank solution, test solution, and reference solution.

[0025] The beneficial effects of adopting the above-mentioned further scheme are as follows: Existing technologies, such as direct injection or headspace injection, suffer from matrix interference in the determination of sulfadoxine, resulting in a spiked recovery rate of approximately 70%. This invention, by improving sample pretreatment, effectively eliminates interference from complex matrices in sulfadoxine, improves sensitivity, and increases the spiked recovery rate to over 90%. Experimental data show that this method has good repeatability (RSD < 5%), a detection limit ( < 10 ppm), and a recovery rate (91.9% ~ 113.5%). Attached Figure Description

[0026] Figure 1 This is a chromatogram of the reference solution prepared in Example 1 of the present invention. Detailed Implementation

[0027] The principles and features of the present invention are described below. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0028] Impurity limits and the basis for these limits The PDE (particulate matter excess) of trichloroethylene was 0.8 mg / day, and the limit was calculated as PDE ÷ MDD = 533 ppm. The limit for aniline (AI) is 720 μg / day; the limit is calculated as AI ÷ MDD = 480 ppm. The TD50 of N,N-dimethylaniline is 125 mg / kg / day, and the limit is calculated as TD50 ÷ 50000 × 50 kg (human body weight) ÷ MDD = 83 ppm.

[0029] Example 1: Preparation of diluent Measure 5.0 ml of cyclohexane into a 100 ml volumetric flask, dilute to the mark with dichloromethane, and shake well to use as a diluent.

[0030] Example 2: Instruments and conditions: Agilent 7890B gas chromatograph, FID detector, column: Phenomen ZB-624 (30m × 0.53mm × 3.0μm), stationary phase: 6% cyanopropylphenyl / 94% dimethylpolysiloxane; detector temperature: 280℃; injection port temperature: 200℃; nitrogen as carrier gas, injection port split ratio: 3:1, nitrogen flow rate: 5.0mL / min; hydrogen flow rate: 30mL / min; air flow rate: 300mL / min; makeup gas: nitrogen, makeup gas flow rate: 25mL / min; column flow rate: 5mL / min; injection volume: 1μL; initial column temperature: 50℃.

[0031] The settings for temperature-elution programming are as follows: (1) Accurately weigh 0.2g of sulfadoxine API, place it in a stoppered test tube, add 2.0ml of 1mol / L sodium hydroxide solution to dissolve it, accurately add 2.0ml of diluent, vortex for 30 seconds, add 1.0g of sodium chloride, vortex for 30 seconds, let stand, and take the lower layer as test solution 1 for later use; repeat the preparation steps of test solution 1 to obtain test solution 2; Accurately measure 2.0 ml of the diluent from Example 1 into a stoppered test tube, add 2.0 ml of 1 mol / L sodium hydroxide solution, vortex for 30 seconds, add 1 g of sodium chloride, vortex for 30 seconds, let stand, and take the lower layer as a blank solution. (2) Accurately weigh 0.666 g of trichloroethylene, 0.60 g of aniline, and 0.104 g of N,N-dimethylaniline, place them in a 25 ml volumetric flask, dissolve and dilute to the mark with cyclohexane, and shake well to prepare reference stock solution ① (the trichloroethylene content in reference stock solution ① is 26.64 mg / ml, the aniline content is 24.0 mg / ml, and the N,N-dimethylaniline content is 4.16 mg / ml). Accurately measure 1.0 ml of reference stock solution ① into a 25 ml volumetric flask, dilute to the mark with cyclohexane, and shake well to prepare reference stock solution ② (the trichloroethylene content in reference stock solution ② is 1066 μg / ml, the aniline content is 960 μg / ml, and the N,N-dimethylaniline content is 166 μg / ml). Accurately measure 1.0 ml of reference stock solution ① into a 25 ml volumetric flask, dilute to the mark with cyclohexane, and shake well to prepare reference stock solution ② (the trichloroethylene content in reference stock solution ② is 1066 μg / ml, the aniline content is 960 μg / ml, and the N,N-dimethylaniline content is 166 μg / ml). 1.0 ml of the reference stock solution ② was placed in a 20 ml volumetric flask, diluted to the mark with dichloromethane, and shaken well to obtain the reference stock solution ③ (containing trichloroethylene 53.28 μg / ml, aniline 48.0 μg / ml, and N,N-dimethylaniline 8.32 μg / ml). 2.0 ml of the reference stock solution ③ was accurately measured and placed in a stoppered test tube. 2.0 ml of 1 mol / L sodium hydroxide solution was added, and the mixture was vortexed for 30 seconds. 1 g of sodium chloride was added, and the mixture was vortexed for 30 seconds. The mixture was allowed to stand, and the lower layer was taken as the reference solution, containing trichloroethylene 53.28 μg / ml, aniline 48.0 μg / ml, and N,N-dimethylaniline 8.32 μg / ml.

[0032] (3) Set the gas chromatography conditions, inject 1 μL of solution into the injection port through the injector and it is instantly vaporized. The vaporized sample is split into two streams. A small portion of the sample enters the capillary column under the guidance of the carrier gas. After separation by the capillary column, it enters the FID detector to obtain the peak area of ​​each component. The gas chromatography conditions are as described above. The first injection is blank solution, followed by six consecutive injections of reference solution, then one injection of test solution 1, one injection of test solution 2, and the last injection of reference solution in the injection sequence. The solution is injected into the gas chromatograph and the chromatogram is recorded. (4) Record the peak areas of trichloroethylene, aniline, and N,N-dimethylaniline and the total peak area in test solution 1 and test solution 2. Calculate the contents of trichloroethylene, aniline, and N,N-dimethylaniline in sulfadoxine according to formula (1). Formula (1) is: ; Among them: A 供试品 The peak area of ​​trichloroethylene / aniline / N,N-dimethylaniline in the test solution; A 对照品 The average peak area of ​​the reference solution is trichloroethylene / aniline / N,N-dimethylaniline. g 供试品 The sample weight is in grams. g 对照品 The sample weight (g) of the reference solution trichloroethylene / aniline / N,N-dimethylaniline; 2 represents the dilution factor of the test sample; 25×25×20 is the dilution factor of the reference standard; 10 6 Unit conversion factor; The above solutions were tested according to the injection sequence. The blank solution should show no significant interfering peaks at the retention times of trichloroethylene, aniline, and N,N-dimethylaniline. The resolution of trichloroethylene, aniline, and N,N-dimethylaniline in the reference solution should be no less than 1.5, the theoretical plate number should be no less than 5000, and the RSD of the peak areas of trichloroethylene, aniline, and N,N-dimethylaniline in the reference solution after six consecutive injections should not exceed 10.0%, and the RSD of the retention time should not exceed 1.0%. Calculated using the external standard method, the test sample should contain no more than 533 ppm of trichloroethylene, no more than 480 ppm of aniline, and no more than 83 ppm of N,N-dimethylaniline.

[0033] The chromatogram of the reference standard is as follows: Figure 1 As shown: In this embodiment, the elution order of the reference solution was dichloromethane, cyclohexane, trichloroethylene, aniline, and N,N-dimethylaniline. The resolutions of trichloroethylene, aniline, and N,N-dimethylaniline were 7.3, 52.6, and 11.3, respectively, with theoretical plate numbers of 47,540, 188,882, and 216,890. The blank solution showed no interference at the retention times of trichloroethylene, aniline, and N,N-dimethylaniline.

[0034] The average peak areas of trichloroethylene, aniline, and N,N-dimethylaniline in the reference solution after six consecutive injections were 104.86, 338.33, and 62.59, respectively. The peak areas of trichloroethylene, aniline, and N,N-dimethylaniline in the test solution were all below the detection limit.

[0035] After six consecutive injections of the reference solution, the results were calculated using the formula. The system precision is shown in Table 1, the detection line and limit of quantitation are shown in Tables 2 and 3, and the linearity test results are shown in Table 4.

[0036] Table 1 System Precision Table 2: Detection Limit Table 3 Limits of Quantification Table 4 Linearity Results From the results in Tables 1-4, we can conclude that: (1) In this embodiment, the peaks of trichloroethylene, aniline, and N,N-dimethylaniline are sharp, with peak height RSD% ≤ 1.6% and retention time RSD% of 0.1%. The system has good precision; (2) In this embodiment, the peaks of trichloroethylene, aniline, and N,N-dimethylaniline are sharp, indicating strong detection ability and high method sensitivity; (3) In this embodiment, the components have a good linear relationship within their respective concentration ranges.

[0037] Example 2: (1) Method accuracy Referring to the results of Example 1, the accuracy of the detection method of the present invention within the concentration range from the limit of quantitation to 120% of the relative limit concentration was verified by designing a recovery experiment. The experiment was conducted at four concentration points: 1) limit of quantitation concentration; 2) 50% of the relative limit concentration; 3) 100% of the relative limit concentration; and 4) 120% of the relative limit concentration. Six samples were measured at each relative limit concentration of 100%, and three samples were measured at each of the other three concentrations. The recovery rates of these spiked samples were calculated, and their average value and precision were evaluated to determine whether the accuracy of the method within this range met the requirements. The results are shown in Table 5. Table 5 Accuracy Results From Table 5, we can obtain: The recoveries of each component were between 80% and 120%, and the RSD of the recoveries of the 15 test samples were all less than 10%, demonstrating that the method of the present invention has good accuracy.

[0038] (6) Method precision The method was repeated by determining the content of each component in 6 100% limit spiking solutions of carcinogens. On different dates, 6 100% level spiking solutions were prepared again by different personnel using different instruments and the same sample preparation method as the repeated tests. These solutions were then injected and tested according to the law as intermediate precision tests. The precision of the method was evaluated by this method. The results are shown in Tables 6 and 7 below.

[0039] Table 6 Repeatability Table 7: Intermediate Precision The results show that the method has good precision.

[0040] (7) Sample determination Nine batches of test samples provided by Jiangsu Jinshen Pharmaceutical Technology Co., Ltd. were analyzed according to the analytical method of Example 1, and the results are shown in Table 8.

[0041] Table 8 Sample Measurement Results Table 8 shows that all results meet the limit requirements. In summary, the method of this invention meets industry standards in all methodological validation parameters, exhibits high sensitivity, short analysis time, strong specificity, good accuracy and precision, and strong repeatability, thus satisfying sample testing requirements.

[0042] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for detecting carcinogens in sulfadoxine, characterized in that, The method includes the following steps: (1) Dissolve the sulfadoxine sample in sodium hydroxide solution, then add diluent and sodium chloride in sequence, let stand, and take the lower layer as the test solution for later use; add sodium hydroxide solution and sodium chloride in sequence to the diluent, let stand, and take the lower layer as the blank solution for later use. (2) Weigh trichloroethylene, aniline, N,N-dimethylaniline, and dissolve them in cyclohexane to prepare reference stock solution ①. Dilute the reference stock solution ① with cyclohexane to prepare reference stock solution ②. Dilute the reference stock solution ② with dichloromethane to prepare reference stock solution ③. Add sodium hydroxide solution and sodium chloride solution to the reference stock solution ③ in sequence, mix and let stand, and take the lower layer as the reference solution. (3) Inject the blank solution, reference solution, and test solution into the gas chromatograph and record the chromatograms; calculate the contents of trichloroethylene, aniline, and N,N-dimethylaniline in the sulfadoxine sample; The formula for the calculation is as follows: Wherein, A 供试品 The peak area of ​​trichloroethylene / aniline / N,N-dimethylaniline in the test solution; The A 对照品 The average peak area of ​​the reference solution is trichloroethylene / aniline / N,N-dimethylaniline. The g 供试品 Weigh the sample for testing; The g 对照品 The sample weight is for the reference solution trichloroethylene / aniline / N,N-dimethylaniline.

2. The method for detecting carcinogens in sulfadoxine according to claim 1, characterized in that, The diluent includes cyclohexane and dichloromethane, with a volume ratio of cyclohexane to dichloromethane of 5:

95.

3. The method for detecting carcinogens in sulfadoxine according to claim 1, characterized in that, The chromatographic column used in step (3) is a medium polar capillary column with a specification of 30m*0.53mm*3.0μm, and the stationary phase is 6% cyanopropylphenyl / 94% dimethylpolysiloxane.

4. The method for detecting carcinogens in sulfadoxine according to claim 1, characterized in that, In the reference solution, the concentration of trichloroethylene is 53.25 μg / ml to 53.34 μg / ml, the concentration of aniline is 47.5 μg / ml to 48.4 μg / ml, and the concentration of N,N-dimethylaniline is 8.25 μg / ml to 8.34 μg / ml.

5. The method for detecting carcinogens in sulfadoxine according to claim 4, characterized in that, In the reference stock solution ①, the concentration of trichloroethylene is 26.63 μg / ml to 26.67 mg / ml, the concentration of aniline is 23.75 μg / ml to 24.20 mg / ml, and the concentration of N,N-dimethylaniline is 4.13 μg / ml to 4.17 mg / ml; In the reference stock solution ②, the concentration of trichloroethylene is 1065.0 μg / ml to 1066.8 μg / ml, the concentration of aniline is 950 μg / ml to 968 μg / ml, and the concentration of N,N-dimethylaniline is 165.0 μg / ml to 166.8 μg / ml; In the reference stock solution ③, the concentration of trichloroethylene is 53.25~53.34 μg / ml, the concentration of aniline is 47.5 μg / ml~48.4 μg / ml, and the concentration of N,N-dimethylaniline is 8.25 μg / ml~8.34 μg / ml.

6. The method for detecting carcinogens in sulfadoxine according to claim 1, characterized in that, The carrier gas used in step (3) is nitrogen, the injection port split ratio is 3:1, and the flow rate of the chromatographic column is 4.5 mL / min to 5.5 mL / min.

7. The method for detecting carcinogens in sulfadoxine according to claim 6, characterized in that, The sample injection volume during the detection described in step (3) is 1 μL.

8. The method for detecting carcinogens in sulfadoxine according to claim 6, characterized in that, In step (3), the hydrogen flow rate during detection is 30 mL / min, the air flow rate is 300 mL / min, and the supplementary gas is nitrogen with a flow rate of 25 mL / min.

9. The method for detecting carcinogens in sulfadoxine according to claim 6, characterized in that, In step (3), the temperature of the vaporization chamber during detection is 250℃ and the temperature of the detector is 280℃. The column chamber adopts programmed temperature rise, with an initial column temperature of 48℃~52℃, an initial column temperature held for 1 min, a heating rate of 13~17℃ / min, a final column temperature of 220℃, and a final column temperature held for 6 min.

10. The method for detecting carcinogens in sulfadoxine according to claim 1, characterized in that, The injection sequence in step (3) is blank solution, reference solution, blank solution, test solution, and reference solution.

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