Method for detecting toxic trace impurities in BPA

Abstract

The invention discloses a method for detecting toxic trace impurities in BPA, and relates to the technical field of drug impurity detection.The toxic trace impurities including 2-iodopropane, 2-chloropropane, 1-iodobutane and 1-chlorobutane are detected at the same time through HS-SPME-GC-MS. The method comprises the operation steps of to-be-detected sample dissolution, matrix modification, impurity enrichment and machine detection. The method for detecting the 2-iodopropane, the 2-chloropropane, the 1-iodobutane and the 1-chlorobutane in the BPA overcomes the technical problems that in the prior art, detection results of trace impurities such as the 2-iodopropane, the 1-iodobutane, the 2-chloropropane and the 1-chlorobutane in the BPA are inaccurate, and reproducibility of a detection method is low, and the method for detecting the 2-iodopropane, the 2-chloropropane, the 1-iodobutane and the 1-chlorobutane in the BPA is simple and accurate to operate.

Description

Technical Field

[0001] This invention relates to the field of pharmaceutical impurity detection technology, specifically to a method for detecting trace amounts of toxic impurities in BPA. Background Technology

[0002] 4-Borate-L-phenylalanine (BPA) is a boron-containing non-natural amino acid that plays an indispensable role in modern oncology. It is a key boron delivery drug that has obtained clinical approval for boron neutron capture therapy (BNCT). BNCT is an advanced, cellular-level precision binary targeted radiotherapy that has shown great therapeutic potential, especially in treating aggressive malignancies that are difficult to treat with conventional therapies, such as glioblastoma multiforme and recurrent head and neck cancer.

[0003] The chemical synthesis routes for obtaining enantiomeric pure L-BPA are quite complex, typically involving multiple steps. A mainstream and widely reported synthetic strategy involves starting with halophenylalanine derivatives and introducing borate groups onto the benzene ring via palladium-catalyzed cross-coupling reactions or organolithium-based boration reactions. For example, using N-protected (S)-4-iodo-L-phenylalanine as a starting material is a common process route.

[0004] This synthetic strategy is a potential source of impurities that directly constitute specific alkyl halides. During complex chemical transformations, iodine atoms in the starting materials, chlorinated solvents or reagents used in the synthesis process, may react with residual alkylating agents, solvents, or their degradation products (e.g., propyl or butyl fragments from the tert-butoxycarbonyl (Boc) protecting group) to generate toxic impurities such as 2-iodopropane, 1-iodobutane, 2-chloropropane, and 1-chlorobutane. These impurities are not random contaminants but process impurities directly related to the established BPA production process, yet specific control strategies must be established. Currently, reproducible research methods are lacking for studying these impurities.

[0005] In existing technology centers, gas chromatography-mass spectrometry (GC-MS) is commonly used to study these substances. However, because BPA samples dissolve in high-boiling-point polar aprotic solvents, they are often soluble in highly polar solvents. Furthermore, 2-iodopropane, 1-iodobutane, 2-chloropropane, and 1-chlorobutane are relatively nonpolar or weakly polar volatile compounds. According to phase equilibrium partition laws (such as Henry's Law), the high solubility of the solute in the liquid phase means its partial pressure in the gas phase will be very low. In other words, the analyte molecules are strongly "bound" in the liquid phase, resulting in a very unfavorable partition coefficient (K) from the liquid to the gas phase. Even after heating to equilibrium, only a very small number of impurity molecules can "escape" into the gas phase for collection and analysis. This leads to inaccurate results for the detection of 2-iodopropane, 1-iodobutane, 2-chloropropane, and 1-chlorobutane. Furthermore, because 2-iodopropane, 1-iodobutane, 2-chloropropane, and 1-chlorobutane are trace substances in pharmaceuticals, their low concentrations may not reach the detection limit. This results in a decrease in the accuracy of GC-MS detection of 2-iodopropane, 1-iodobutane, 2-chloropropane, and 1-chlorobutane, leading to inaccurate experimental results. Summary of the Invention

[0006] The purpose of this invention is to solve the technical problems of inaccurate detection results and low reproducibility of detection methods for trace impurities 2-iodopropane, 1-iodobutane, 2-chloropropane, and 1-chlorobutane in BPA in the prior art. This invention provides the following technical solution:

[0007] A method for detecting toxic trace impurities in BPA, using HS-SPME-GC-MS to simultaneously detect toxic trace impurities 2-iodopropane, 2-chloropropane, 1-iodobutane and 1-chlorobutane.

[0008] A method for detecting trace toxic impurities in BPA includes the following steps:

[0009] S1: Dissolving the sample: Accurately weigh the BPA raw material into a headspace vial and dissolve it in a polar organic solvent; S2: Matrix modification: Add a dry, anhydrous, non-volatile inorganic salt to the solution prepared in step S1, seal the headspace vial, and shake to mix.

[0010] S3: Impurity enrichment: Headspace solid-phase microextraction (HS-SPME) device is used to adsorb and desorb toxic trace impurities into another headspace vial;

[0011] S4: On-machine testing: Take the gas from the headspace sample vial in step S3 and analyze it by GC-MS.

[0012] The polar organic solvent in step S1 is any one of DMSO, DMF, N,N-dimethylacetamide, and N-methyl-2-pyrrolidine.

[0013] The anhydrous nonvolatile inorganic salt in step S2 is any one of anhydrous sodium sulfate, anhydrous magnesium sulfate, anhydrous calcium chloride, and potassium carbonate.

[0014] In step S1, the polar organic solvent is DMSO; in step S2, the anhydrous non-volatile inorganic salt is anhydrous sodium sulfate.

[0015] A method for detecting trace toxic impurities in BPA further includes: plotting a standard curve; wherein plotting the standard curve includes the following steps:

[0016] S01: Accurately weigh 2-iodopropane, 2-chloropropane, 1-iodobutane and 1-chlorobutane standards, place them in headspace vials respectively, add the same polar organic solvent as in step S1 to dissolve them, and obtain standard solutions.

[0017] S02: Dilute each standard solution to obtain standard test solutions of different concentrations;

[0018] S03: Perform matrix modification, impurity enrichment, and instrument detection on the standard test solution in sequence according to steps S2 to S4; the instrument detection conditions are the same as those in step S4.

[0019] In step S3, the adsorbent of headspace solid phase microextraction (HS-SPME) is coated with a composite extraction fiber containing any one of divinylbenzene, carbon molecular sieve and polydimethylsiloxane.

[0020] In step S3, the settings for headspace solid-phase microextraction (HS-SPME) are as follows:

[0021] Sample equilibrium temperature: 60℃-80℃; Sample equilibrium time: 15min-30min; SPME fiber extraction time: 20-40min; Desorption temperature: 250℃; Desorption time: 2-4min.

[0022] Preferably, in step S3, the settings for headspace solid-phase microextraction (HS-SPME) are as follows:

[0023] Sample equilibrium temperature: 70℃; Sample equilibrium time: 20 min; SPME fiber extraction time: 30 min; Desorption temperature: 250℃; Desorption time: 2 min.

[0024] In step S4, the GC-MS configuration parameters are as follows:

[0025] Chromatographic column: Medium polarity column;

[0026] Carrier gas: Helium;

[0027] Flow rate: 1.2 mL / min;

[0028] Injection port mode: splitless, splitless time: 2 min

[0029] Temperature program: Initial temperature 40℃, hold for 5 min; then increase to 220℃ at a rate of 10℃ / min, hold for 2 min;

[0030] MS transmission line temperature: 250℃;

[0031] MS ion source temperature: 230℃;

[0032] Ionization method: Electron bombardment (EI), energy 70 eV;

[0033] Acquisition mode: Ion Monitoring and Detection (SIM) mode.

[0034] The present invention has the following advantages:

[0035] (1) This invention proposes for the first time a method using HS-SPME-GC-MS headspace solid phase microextraction gas chromatography-mass spectrometry, which realizes the simultaneous detection of four trace substances in BPA toxicity: 2-iodopropane, 1-iodobutane, 2-chloropropane and 1-chlorobutane. Compared with single detection, it saves detection time and steps. At the same time, the detection method has high laboratory reproducibility, detection stability and accuracy.

[0036] (2) This invention employs a polar organic solvent to dissolve BPA, and then adds anhydrous inorganic salts to the dissolved BPA solution. This matrix modification significantly alters the unfavorable phase distribution equilibrium in the solution, allowing trace toxic impurities to "escape" from the organic solvent into the headspace gas phase, enabling their collection and analysis. The detection method provided by this invention significantly increases the activity coefficient of relatively nonpolar analytes, thereby greatly improving the distribution efficiency of the target analyte from the liquid phase to the headspace gas phase, and consequently improving the accuracy of detection.

[0037] (3) This invention uses headspace solid-phase microextraction (HS-SPME) to enrich toxic trace impurities, thereby improving the detection limit. Through the synergistic effect of matrix modification and analyte preconcentration, this invention achieves a huge and unexpected improvement in analytical signal intensity and signal-to-noise ratio, providing extremely high reliability and safety for analytical results. It perfectly solves the problems that existing technologies cannot overcome and provides a strong technical guarantee for ensuring the quality and safety of high-dose drug BPA. Attached Figure Description

[0038] Figure 1 The GC-MS chromatogram of 2-iodopropane in BPA;

[0039] Figure 2 The standard curve for 2-iodopropane;

[0040] Figure 3 The GC-MS chromatogram of 2-chloropropane in BPA;

[0041] Figure 4 The standard curve for 2-chloropropane;

[0042] Figure 5 The GC-MS chromatogram of 1-iodobutane in BPA;

[0043] Figure 6 The standard curve for 1-iodobutane;

[0044] Figure 7 The GC-MS chromatogram of 1-chlorobutane in BPA;

[0045] Figure 8 This is the standard curve for 1-chlorobutane. Detailed Implementation

[0046] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0047] Therefore, the following detailed description of embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely illustrates some embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0048] It should be noted that, unless otherwise specified, the embodiments and features and technical solutions in the present invention can be combined with each other.

[0049] Example 1:

[0050] The method for detecting toxic trace impurities in BPA uses HS-SPME-GC-MS to simultaneously detect toxic trace impurities 2-iodopropane, 2-chloropropane, 1-iodobutane, and 1-chlorobutane.

[0051] Specifically, the following steps are included:

[0052] S1: Dissolving the test sample: Accurately weigh 104.68 mg of BPA raw material into a 20 mL headspace vial, add 2.0 mL of polar organic solvent DMSO, and vortex the headspace vial until the BPA sample is completely dissolved to form a clear test sample solution.

[0053] S2: Matrix Modification: Add 400.00 mg of dried anhydrous sodium sulfate to the solution prepared in step S1, seal the headspace vial, and shake to mix thoroughly, ensuring uniform dispersion of the anhydrous sodium sulfate in the DMSO solution. The dried anhydrous sodium sulfate is prepared by selecting analytical grade anhydrous sodium sulfate (Na₂SO₄), drying it at 105°C for 30 min to remove trace amounts of moisture. When sealing the headspace vial, immediately cap it with an aluminum cap fitted with a PTFE or silicone septum to prevent the loss of volatile impurities, which could lead to inaccurate test results.

[0054] S3: Impurity Enrichment: Headspace solid-phase microextraction (HS-SPME) is used to adsorb and desorb toxic trace impurities into another headspace vial. The adsorbent for HS-SPME is a composite extraction fiber coated with divinylbenzene.

[0055] The headspace solid-phase microextraction (SPE) parameters are as follows: sample equilibration temperature: 70℃; sample equilibration time: 20 min; SPME fiber extraction time: 30 min.

[0056] After extraction for 30 min, another headspace vial was used to desorb from the headspace solid-phase microextraction (HS-SPME) absorber. The desorption temperature was 250℃ and the desorption time was 2 min.

[0057] S4: On-machine detection: Take the gas from the headspace sample vial after desorption in step S3, analyze it by GC-MS, and calculate the content.

[0058] The configuration parameters for GC-MS are as follows:

[0059] Column: Medium polarity column; preferably, the stationary phase is 6% cyanopropylphenyl-94% dimethylpolysiloxane. It is recommended to use an equivalent column such as Agilent VF-624ms, DB-624, or Restek Rxi-624Sil MS. In this embodiment, an Agilent VF-624ms column with dimensions of 30m × 0.25mm and a diameter of 1.4μm is used.

[0060] Carrier gas: Helium.

[0061] Flow rate: 1.2 mL / min;

[0062] Injection port mode: splitless, splitless time: 2 min

[0063] Temperature program: Initial temperature 40℃, hold for 5 min; then increase to 220℃ at a rate of 10℃ / min, hold for 2 min;

[0064] MS transmission line temperature: 250℃;

[0065] MS ion source temperature: 230℃;

[0066] Ionization method: Electron bombardment (EI), energy 70 eV;

[0067] Acquisition mode: Ion Monitoring and Detection (SIM) mode.

[0068] The specific selected ion monitoring (SIM) parameters for 2-iodopropane, 2-chloropropane, 1-iodobutane, and 1-chlorobutane are detailed in the table below:

[0069]

[0070] Plotting the standard curve: The plotting of the standard curve includes the following steps:

[0071] S01: Accurately weigh 2-iodopropane, 2-chloropropane, 1-iodobutane and 1-chlorobutane standards and place them in headspace vials respectively. Add DMSO to dissolve them to obtain standard solutions.

[0072] S02: Dilute each standard solution to obtain standard test solutions of different concentrations;

[0073] S03: The standard test solution was subjected to matrix modification, impurity enrichment and instrument detection in sequence according to steps S2 to S4 in Example 1; the instrument detection conditions and headspace solid phase microextraction (HS-SPME) were the same as those in step S4.

[0074] See Figures 1-8 According to GC-MS analysis, the concentrations of the standards prepared for 2-iodopropane, 2-chloropropane, 1-iodobutane, and 1-chlorobutane, the corresponding peak areas, and the equations of the standard curves prepared by the standard curve method are detailed in the table below:

[0075]

[0076]

[0077] In this embodiment, the linear correlation coefficients of 2-iodopropane, 2-chloropropane, 1-iodobutane, and 1-chlorobutane were all higher than 0.99, indicating good linear correlation. Calculations showed that the limits of quantitation (LOQ) for 2-iodopropane, 2-chloropropane, 1-iodobutane, and 1-chlorobutane were all less than 10 ppb, far below the 60 ppb limit required in the ICH M7(R2) guidance, "Assessing and controlling DNA-active (mutagenic) impurities in pharmaceutical products to limit potential carcinogenic risks," indicating that the detection method meets the requirements.

[0078] Substituting the peak areas of the trace toxic impurities 2-iodopropane, 2-chloropropane, 1-iodobutane, and 1-chlorobutane obtained by GC-MS detection into the corresponding linear equations yields the toxicity of each impurity. Calculations showed that the contents of 2-iodopropane, 2-chloropropane, 1-iodobutane, and 1-chlorobutane were 25.5 ppb, 12.5 ppb, 15.6 ppb, and 13.3 ppb, respectively, meeting the requirements of the regulation "Assessing and controlling DNA-active (mutagenic) impurities in pharmaceuticals to limit potential carcinogenic risks."

[0079] Example 2:

[0080] The method for detecting toxic trace impurities in BPA uses HS-SPME-GC-MS to simultaneously detect toxic trace impurities 2-iodopropane, 2-chloropropane, 1-iodobutane, and 1-chlorobutane.

[0081] Specifically, the following steps are included:

[0082] S1: Dissolving the test sample: Accurately weigh 103.52 mg of BPA active pharmaceutical ingredient from the same batch as in Example 1 into a 20 mL headspace vial, add 2.0 mL of polar organic solvent N,N-dimethylformamide, and vortex the headspace vial until the BPA sample is completely dissolved to form a clear test sample solution.

[0083] S2: Matrix Modification: Add 400.0 mg of dried anhydrous magnesium sulfate to the solution prepared in step S1, seal the headspace vial, and shake to mix thoroughly, ensuring uniform dispersion of the anhydrous magnesium sulfate in the N,N-dimethylformamide solution. The dried anhydrous magnesium sulfate is prepared by selecting analytical grade anhydrous magnesium sulfate (MgSO4), drying it at 105°C for 30 min to remove trace moisture, and obtaining dried anhydrous magnesium sulfate. When sealing the headspace vial, immediately cap it with an aluminum cap fitted with a PTFE or silicone septum to prevent the loss of volatile impurities, which could lead to inaccurate test results.

[0084] S3: Impurity Enrichment: Headspace solid-phase microextraction (HS-SPME) is used to adsorb and desorb toxic trace impurities into another headspace vial. The adsorbent for HS-SPME is a composite extraction fiber coated with divinylbenzene.

[0085] The headspace solid-phase microextraction (SPE) parameters are as follows: sample equilibration temperature: 60℃; sample equilibration time: 15 min; SPME fiber extraction time: 20 min.

[0086] After extraction for 30 min, another headspace vial was used to desorb from the headspace solid-phase microextraction (HS-SPME) absorber. The desorption temperature was 250℃ and the desorption time was 2 min.

[0087] S4: On-machine detection: Take the gas from the headspace injection bottle after desorption in step S3, and perform GC-MS detection under the same conditions as in Example 1. Calculate the content using the standard curve method.

[0088] In calculating the contents of 2-iodopropane, 2-chloropropane, 1-iodobutane, and 1-chlorobutane, the standard curve in Example 1 was used to calculate the contents of 2-iodopropane, 2-chloropropane, 1-iodobutane, and 1-chlorobutane to be 25.0 ppb, 11.9 ppb, 16.4 ppb, and 13.9 ppb, respectively.

[0089] Example 3:

[0090] The method for detecting toxic trace impurities in BPA uses HS-SPME-GC-MS to simultaneously detect toxic trace impurities 2-iodopropane, 2-chloropropane, 1-iodobutane, and 1-chlorobutane.

[0091] Specifically, the following steps are included:

[0092] S1: Dissolving the test sample: Accurately weigh 100.0 mg of the same batch of BPA active pharmaceutical ingredient as in Example 1 into a 20 mL headspace vial, add 2.0 mL of the polar organic solvent N,N-dimethylacetamide, and vortex the headspace vial until the BPA sample is completely dissolved to form a clear test sample solution.

[0093] S2: Matrix Modification: Add 400.0 mg of dried anhydrous calcium chloride to the solution prepared in step S1, seal the headspace vial, and shake to mix thoroughly, ensuring uniform dispersion of the anhydrous calcium chloride in the N,N-dimethylacetamide solution. The dried anhydrous calcium chloride is prepared by selecting analytical grade anhydrous calcium chloride (CaCl2), drying it at 105°C for 30 min to remove trace amounts of moisture. When sealing the headspace vial, immediately cap it with an aluminum cap fitted with a PTFE or silicone septum to prevent the loss of volatile impurities, which could lead to inaccurate test results.

[0094] S3: Impurity Enrichment: Headspace solid-phase microextraction (HS-SPME) is used to adsorb and desorb toxic trace impurities into another headspace vial. The adsorbent for HS-SPME is a composite extraction fiber coated with divinylbenzene.

[0095] The headspace solid-phase microextraction (SPE) parameters are as follows: sample equilibrium temperature: 80℃; sample equilibrium time: 30 min; SPME fiber extraction time: 40 min.

[0096] After extraction for 30 min, another headspace vial was used to desorb from the headspace solid-phase microextraction (HS-SPME) absorber. The desorption temperature was 250℃ and the desorption time was 4 min.

[0097] S4: On-machine detection: Take the gas from the headspace injection bottle after desorption in step S3, and perform GC-MS detection under the same conditions as in Example 1. Calculate the content using the standard curve method.

[0098] In calculating the contents of 2-iodopropane, 2-chloropropane, 1-iodobutane, and 1-chlorobutane, the standard curve in Example 1 was used to calculate the contents of 2-iodopropane, 2-chloropropane, 1-iodobutane, and 1-chlorobutane to be 25.3 ppb, 12.2 ppb, 15.1 ppb, and 12.9 ppb, respectively.

[0099] Example 4:

[0100] The method for detecting toxic trace impurities in BPA uses HS-SPME-GC-MS to simultaneously detect toxic trace impurities 2-iodopropane, 2-chloropropane, 1-iodobutane, and 1-chlorobutane.

[0101] Specifically, the following steps are included:

[0102] S1: Dissolving the test sample: Accurately weigh 100.0 mg of the same batch of BPA active pharmaceutical ingredient as in Example 1 into a 20 mL headspace vial, add 2.0 mL of the polar organic solvent N-methyl-2-pyrrolidine, and vortex the headspace vial until the BPA sample is completely dissolved to form a clear test sample solution.

[0103] S2: Matrix Modification: Add 400.0 mg of dried anhydrous potassium carbonate to the solution prepared in step S1, seal the headspace vial, and shake to mix thoroughly, ensuring uniform dispersion of the anhydrous potassium carbonate in the N-methyl-2-pyrrolidine solution. The dried anhydrous potassium carbonate is prepared by selecting analytical grade anhydrous potassium carbonate (K₂CO₃), drying it at 105°C for 30 min to remove trace amounts of moisture. When sealing the headspace vial, immediately cap it with an aluminum cap fitted with a PTFE or silicone septum to prevent the loss of volatile impurities, which could lead to inaccurate test results.

[0104] S3: Impurity Enrichment: Headspace solid-phase microextraction (HS-SPME) is used to adsorb and desorb toxic trace impurities into another headspace vial. The adsorbent for HS-SPME is a composite extraction fiber coated with divinylbenzene.

[0105] The headspace solid-phase microextraction (SPE) parameters are as follows: sample equilibrium temperature: 70℃; sample equilibrium time: 25 min; SPME fiber extraction time: 35 min.

[0106] After extraction for 30 min, another headspace vial was used to desorb from the headspace solid-phase microextraction (HS-SPME) absorber. The desorption temperature was 250℃ and the desorption time was 3 min.

[0107] S4: On-machine detection: Take the gas from the headspace injection bottle after desorption in step S3, and perform GC-MS detection under the same conditions as in Example 1. Calculate the content using the standard curve method.

[0108] In calculating the contents of 2-iodopropane, 2-chloropropane, 1-iodobutane, and 1-chlorobutane, the standard curve in Example 1 was used to calculate the contents of 2-iodopropane, 2-chloropropane, 1-iodobutane, and 1-chlorobutane to be 24.6 ppb, 12.6 ppb, 15.7 ppb, and 13.5 ppb, respectively.

[0109] Example 5: Spiked Recycling

[0110] S1: Dissolving the test sample: Accurately weigh 100.0 mg of BPA raw material from the same batch as in Example 1 into three 20 mL headspace vials. Add 50 μg each of 2-iodopropane, 2-chloropropane, 1-iodobutane, and 1-chlorobutane to the first headspace vial. Add 100 μg each of 2-iodopropane, 2-chloropropane, 1-iodobutane, and 1-chlorobutane to the second headspace vial. Add 150 μg each of 2-iodopropane, 2-chloropropane, 1-iodobutane, and 1-chlorobutane to the third headspace vial. Then add 2.0 mL of polar organic solvent DMSO to each headspace vial. Vortex the headspace vials until the BPA sample is completely dissolved. Then add the solution to form a clear test sample solution.

[0111] S2: Matrix Modification: Add 400.0 mg of dry anhydrous sodium sulfate to each headspace vial of the solution prepared in step S1, seal the vial, and shake to mix thoroughly, ensuring uniform dispersion of the anhydrous sodium sulfate in the DMSO solution. The dry anhydrous sodium sulfate is prepared by selecting analytical grade anhydrous sodium sulfate (Na₂SO₄), drying it at 105°C for 30 min to remove trace amounts of moisture. When sealing the headspace vials, immediately cap them with an aluminum cap fitted with a PTFE or silicone septum to prevent the loss of volatile impurities, which could lead to inaccurate test results.

[0112] S3: Impurity Enrichment: Headspace solid-phase microextraction (HS-SPME) is used to adsorb and desorb toxic trace impurities into another headspace vial. The adsorbent for HS-SPME is a composite extraction fiber coated with divinylbenzene.

[0113] The headspace solid-phase microextraction (SPE) parameters are as follows: sample equilibration temperature: 70℃; sample equilibration time: 20 min; SPME fiber extraction time: 30 min.

[0114] After extraction for 30 min, another headspace vial was used to desorb from the headspace solid-phase microextraction (HS-SPME) absorber. The desorption temperature was 250℃ and the desorption time was 2 min.

[0115] S4: On-machine detection: Take the gas from the three headspace vials after desorption in step S3, analyze it by GC-MS, and calculate the content.

[0116] The calculated recoveries are detailed in the table below:

[0117]

[0118] Example 6: Stability Test

[0119] Using the same batch of BPA active pharmaceutical ingredient as in Example 1, the above experiment was repeated 6 times, following the exact same operating procedures, GC-MS detection methods, and calculation methods as in Example 1. Detailed detection results are shown in the table below:

[0120]

[0121]

[0122] Comparative Example 1:

[0123] Comparative Example 1 used the same batch of BPA as Example 1, and employed the same detection and quantitative analysis methods. The contents of trace toxic impurities 2-iodopropane, 2-chloropropane, 1-iodobutane, and 1-chlorobutane were simultaneously detected by HS-SPME-GC-MS. The difference was that anhydrous sodium sulfate was not added in Comparative Example 1, i.e., the matrix modification step S2 was not performed. Using the same GC-MS conditions as Example 1, the contents of 2-iodopropane, 2-chloropropane, 1-iodobutane, and 1-chlorobutane in Comparative Example 1 were calculated to be 20.3 ppb, 7 ppb, 6.6 ppb, and 8.3 ppb, respectively. The data results for Comparative Example 1 and Example 1 are as follows:

[0124]

[0125] Compared to Example 1, the signal-to-noise ratio (SNR) of trace impurities in the BPA solution with added anhydrous sodium sulfate was more than 10 times higher than that in the solution without added anhydrous sodium sulfate, representing a difference of one order of magnitude. This indicates a significant improvement in the accuracy of the detection results. The most direct manifestation of this improvement is the marked increase in the detection levels of 2-iodopropane, 2-chloropropane, 1-iodobutane, and 1-chlorobutane. This order-of-magnitude increase in sensitivity is a direct manifestation of the "non-aqueous system salting-out effect" proposed in this invention. This effect effectively drives trace impurities that are difficult to volatilize due to their high solubility to the headspace, allowing them to be efficiently captured and enriched by SPME fibers. This effect, especially in the DMSO system, significantly improves the accuracy for such toxic trace impurities.

[0126] Comparative Example 2:

[0127] Comparative Example 2 used the same batch of BPA as Example 1, and employed the same detection and quantitative analysis methods. The contents of toxic trace impurities 2-iodopropane, 2-chloropropane, 1-iodobutane, and 1-chlorobutane were simultaneously detected by HS-SPME-GC-MS. The difference was that step S3, impurity enrichment, was omitted in Comparative Example 2. The headspace vial from step S2 was directly analyzed under the same GC-MS conditions as in Example 1. The calculated contents of 2-iodopropane, 2-chloropropane, 1-iodobutane, and 1-chlorobutane in Comparative Example 1 were all undetectable.

[0128] Example 7:

[0129] Example 7 used the same batch of BPA as Example 1, and employed the same detection and quantitative analysis methods. The contents of toxic trace impurities 2-iodopropane, 2-chloropropane, 1-iodobutane, and 1-chlorobutane were simultaneously detected by HS-SPME-GC-MS. The difference lay in the headspace solid-phase microextraction (HS-SPME) parameters: sample equilibration temperature: 60°C; sample equilibration time: 10 min; SPME fiber extraction time: 15 min; after 15 min of extraction, another headspace vial was used to desorb from the HS-SPME absorber at a desorption temperature of 250°C and a resolution time of 1 min. The calculated contents of 2-iodopropane, 2-chloropropane, 1-iodobutane, and 1-chlorobutane were 22.5 ppb, 10.3 ppb, 12.4 ppb, and 10.4 ppb, respectively.

[0130] Example 8:

[0131] Example 8 used the same batch of BPA as Example 1, and employed the same detection and quantitative analysis methods. The contents of toxic trace impurities 2-iodopropane, 2-chloropropane, 1-iodobutane, and 1-chlorobutane were simultaneously detected by HS-SPME-GC-MS. The difference lay in the headspace solid-phase microextraction (HS-SPME) parameters used in Example 8, as follows: sample equilibration temperature: 90℃; sample equilibration time: 40 min; SPME fiber extraction time: 45 min; after 45 min of extraction, another headspace vial was used to desorb from the headspace solid-phase microextraction (HS-SPME) absorber at a temperature of 250℃ and a resolution time of 5 min. The calculated contents of 2-iodopropane, 2-chloropropane, 1-iodobutane, and 1-chlorobutane were 24.9 ppb, 12.3 ppb, 15.9 ppb, and 13.6 ppb, respectively.

[0132] The experimental results of Examples 1-4 demonstrate that when BPA raw material is dissolved in a polar organic solvent, the addition of anhydrous non-volatile inorganic salts to the solvent ensures that trace toxic impurities escape into the gas phase, preventing them from being "bound" in the liquid and improving detection accuracy. Comparing Examples 1-4 and Comparative Example 1, in a DMSO solution of BPA without the addition of anhydrous sodium sulfate, the vaporization rate of trace toxic impurities is low, resulting in lower detection rates and inaccurate results. Comparing Examples 1-4 and Comparative Example 2, headspace solid-phase microextraction (HS-SPME) enriches the trace impurities, achieving concentrations within the detection limit range and ensuring their detection. Comparing Examples 1 and Examples 7-8, the solid-phase microextraction parameters provided by this invention enable stable vaporization and enrichment of trace toxic impurities in BPA. The spiked recovery experiment in Example 6 and the stability test in Example 7 show that the average recovery rate of all analytes is within the ideal range of 91.6%-106.8%, and the repeatability (n=6) RSD < 5.0%, all of which meet the detection requirements; the detection method provided by the present invention is stable and accurate.

[0133] In summary, this invention provides a simple, stable, accurate, and reproducible method for detecting trace impurities in BPA, namely 2-iodopropane, 2-chloropropane, 1-iodobutane, and 1-chlorobutane. Through simple dissolution, matrix modification, and impurity enrichment operations, simultaneous detection of these four substances is achieved under the same detection conditions. The core principle of this invention lies in creatively applying the physicochemical phenomenon of the "salting-out effect" to a non-aqueous, polar, aprotic solvent system to solve the technical problem of trace impurities being "encapsulated" by the solvent and not easily volatilized.

[0134] Taking anhydrous sodium sulfate as an example, when an inorganic salt like anhydrous sodium sulfate (Na₂SO₄) is added to DMSO, sodium ions (Na⁺) and sulfate ions (SO₄²⁻) form strong ion-dipole interactions with the negatively charged oxygen atoms and positively charged sulfur atoms in the DMSO molecules. This interaction "binds" a large number of DMSO solvent molecules, forming an ionized solvation layer at the microscopic level, thereby significantly increasing the apparent polarity and ionic strength of the entire solvent system. For the relatively nonpolar alkyl halide analytes 2-iodopropane, 2-chloropropane, 1-iodobutane, and 1-chlorobutane dissolved in it, the sharp increase in solvent polarity leads to a significant decrease in their solubility in the solvent. According to Henry's Law, a decrease in the solubility of a solute in the liquid phase directly leads to a proportional increase in its equilibrium partial pressure in the gas phase. In short, the analytes 2-iodopropane, 2-chloropropane, 1-iodobutane, and 1-chlorobutane are more effectively "driven out" or "salted out" from the liquid phase into the headspace gas phase. This significantly altered the unfavorable phase distribution equilibrium, resulting in an order-of-magnitude increase in analyte concentration in the headspace. Combined with subsequent high-efficiency HS-SPME extraction, this greatly improved the detection accuracy of analytes 2-iodopropane, 2-chloropropane, 1-iodobutane, and 1-chlorobutane.

[0135] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for detecting trace impurities in BPA poisoning, characterized by, Toxic trace impurities 2-iodopropane, 2-chloropropane, 1-iodobutane and 1-chlorobutane are simultaneously detected by HS-SPME-GC-MS.

2. The method of claim 1, wherein the BPA is bisphenol A. 3 The method comprises the following steps: S1: dissolving the sample to be tested: accurately weigh the BPA raw material drug into a headspace bottle, and add a polar organic solvent for dissolution; S2: matrix modification: add dry anhydrous non-volatile inorganic salt to the solution prepared in step S1, seal the headspace bottle, and shake to mix; S3: impurity enrichment: use a headspace solid-phase microextraction (HS-SPME) device to adsorb and desorb the toxic trace impurities into another headspace sample bottle; S4: instrument detection: take the gas in the headspace sample bottle in step S3 for GC-MS sample analysis.

3. A method of detecting trace impurities in BPA poisoning according to claim 2, characterized by, The polar organic solvent in step S1 is any one of DMSO, DMF, N, N-dimethylacetamide and N-methyl-2-pyrrolidine.

4. The method of claim 3, wherein the BPA is bisphenol A. 5 The anhydrous non-volatile inorganic salt in step S2 is any one of anhydrous sodium sulfate, anhydrous magnesium sulfate, anhydrous calcium chloride and potassium carbonate.

5. A method of detecting toxic trace impurities in BPA according to claim 4, wherein, In step S1, the polar organic solvent is DMSO; in step S2, the anhydrous non-volatile inorganic salt is anhydrous sodium sulfate.

6. The method of claim 2, wherein the BPA is a BPA isophthalic acid (IPA) mixture. It also includes: drawing of a standard curve; wherein the drawing of the standard curve comprises the following steps: S01: accurately weigh 2-iodopropane, 2-chloropropane, 1-iodobutane and 1-chlorobutane standards, and then place them in a headspace bottle, add the same polar organic solvent as in step S1 for dissolution to obtain standard solutions; S02: dilute each standard solution to obtain standard sample solutions with different concentrations; S03: perform matrix modification, impurity enrichment and instrument detection on the standard sample solutions in turn according to steps S2 to S4; the instrument detection conditions are consistent with the detection conditions of step S4.

7. The method for detecting trace toxic impurities in BPA as described in claim 2, characterized in that, In step S3, the adsorbent of the headspace solid-phase microextraction (HS-SPME) is coated with a composite extraction fiber of any one of divinylbenzene, carbon molecular sieve and polydimethylsiloxane.

8. A method of detecting trace impurities in BPA poisoning according to claim 7, wherein, In step S3, the setting parameters of the headspace solid-phase microextraction (HS-SPME) are as follows: Sample equilibration temperature: 60-80℃; sample equilibration time: 15-30min; SPME fiber extraction time: 20-40min; desorption temperature: 250℃; desorption time: 2-4min.

9. A method of detecting trace impurities in BPA poisoning according to claim 8, wherein, In step S3, the setting parameters of the headspace solid-phase microextraction (HS-SPME) are as follows: Sample equilibration temperature: 70℃; sample equilibration time: 20min; SPME fiber extraction time: 30min; desorption temperature: 250℃; desorption time: 2min.

10. The method for detecting trace toxic impurities in BPA as described in claim 2, characterized in that, In step S4, the setting condition parameters of GC-MS are as follows: Chromatographic column: medium polarity chromatographic column; Carrier gas: helium; Flow rate: 1.2mL / min; Injection port mode: splitless, splitless time: 2min Temperature program: initial temperature 40℃, hold for 5min; then increase the temperature to 220℃ at a rate of 10℃ / min, hold for 2min; MS transfer line temperature: 250℃; MS ion source temperature: 230℃; Ionization mode: electron impact (EI), energy 70eV; Acquisition mode: ion monitoring (SIM) mode.

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