Method for splitting biotin enantiomer by adopting simulated moving bed chromatography

Abstract

The invention discloses a method for splitting biotin enantiomers by simulated moving bed chromatography, which comprises the following steps: injecting a salt solution of a D-biotin crude product to be separated into a feed point of the simulated moving bed chromatography, and injecting an eluent into an eluent input point of the simulated moving bed chromatography, respectively obtaining high-purity D-biotin salt and low-purity D-biotin salt from a raffinate extraction point and an extracting solution extraction point of the simulated moving bed chromatography; the stationary phase of the simulated moving bed chromatography is a polystyrene / divinylbenzene reversed-phase polymer filler with the particle size range of 5-50 [mu] m, and the uniformity coefficient is 1.0-1.3; the eluent is an alkaline aqueous solution. Compared with a freezing crystallization mode, the method has the advantages of low energy consumption, low operation cost and high separation efficiency, can be continuously operated, and is suitable for industrial production.

Description

Technical Field

[0001] The invention belongs to the technical field of chiral compound separation, and particularly relates to a method for separating biotin enantiomers by using simulated moving bed chromatography. Background Art

[0002] D-biotin, also known as vitamin H, vitamin B7 and coenzyme R, belongs to the B group of water-soluble vitamins. It is an indispensable nutrient for maintaining the normal physiological functions of animal bodies and is widely used in medicine, cosmetics, food additives and feed.

[0003] The widespread use of D-biotin has promoted its synthesis, of which chemical synthesis is relatively mature. However, the biotin obtained by chemical synthesis contains two configurations: D- and L-forms. The current method for resolving D,L-biotin is usually to first react D,L-biotin with an optically active substance to produce diastereomeric derivatives. The derivatives are then separated by appropriate separation methods (crystallization) using the differences in their properties (different solubility in solvents). Finally, the pH of the solution is adjusted to restore the derivatives to the acid. This separation method is cumbersome and involves the use and recovery of derivatizing agents, resulting in high separation costs.

[0004] Patent CN109251210A discloses a method for purifying D-biotin. This method involves dissolving crude D-biotin in a water-low-carbon alcohol mixed solvent under heating, stirring, and reflux. The resulting product is then decolorized with activated carbon and cooled for crystallization. This method does not involve chiral separation of D,L-biotin and is more suitable for recrystallization purification of crude D-biotin.

[0005] The D-biotin purification method disclosed in patent CN101195629B requires recrystallization of D-biotin using a mixed solvent of lower alkyl alcohol and glacial acetic acid to remove impurities. If the D-biotin obtained in this step does not meet the optical rotation requirements, L-arginine is used as a chiral resolving agent and dissolved in a mixture of water and lower alkyl alcohol. Taking advantage of the difference in the properties of D-biotin arginine salt (insoluble in lower alkyl alcohol solutions) and L-biotin arginine salt (soluble in lower alkyl alcohol solutions), D-biotin is precipitated as a solid by freeze crystallization, resulting in a D-biotin yield of 84.7% to 93.2%. This method employs the classic chiral compound resolution method of forming diastereomeric derivatives to resolve D and L-biotin. L-arginine is introduced during the resolution process, resulting in a recovery rate of only 73.2%. This results in cumbersome purification steps and high production costs, and the freeze crystallization process is energy-intensive.

[0006] It can be seen that the existing D, L-biotin enantiomer separation uses the classic method of forming diastereomeric salts, which has cumbersome operation steps and high separation costs after the introduction of derivatization reagents. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a method for resolving biotin enantiomers using simulated moving bed chromatography. Compared with the classic chiral isomer separation method of forming diastereomeric salts, this method has the advantages of low operating cost and high separation efficiency, and can be operated continuously, making it suitable for industrial production.

[0008] A method for separating biotin enantiomers using simulated moving bed chromatography, comprising:

[0009] A salt solution of a crude D-biotin product to be separated is injected into a feed point of a simulated moving bed chromatography, an eluent is injected into an eluent input point of the simulated moving bed chromatography, and a high-purity D-biotin product and a low-purity D-biotin product are obtained from a raffinate extraction point and an extract extraction point of the simulated moving bed chromatography, respectively;

[0010] The stationary phase of the simulated moving bed chromatography is a polystyrene / divinylbenzene type reverse phase polymer filler.

[0011] The eluent is an alkaline aqueous solution.

[0012] The method of the present invention optimizes the use of an inexpensive conventional stationary phase (achiral filler) and utilizes the slight difference in the partition coefficients of biotin enantiomers in the stationary phase and the mobile phase to directly resolve biotin using simulated moving bed technology, thereby avoiding the use and recovery of a large amount of derivatizing agents. The purity of D-biotin in the final product can be as high as over 99.90%, and the yield of D-biotin can be as high as 96.00%.

[0013] Preferably, the stationary phase is a reverse phase polymer filler with a particle size ranging from 5 to 50 μm and a uniformity coefficient of 1.0 to 1.3, specifically PolyRP-100, PolyRP-300, XT-20, or XT-30.

[0014] Preferably, the simulated moving bed chromatography is composed of 4 to 32 identical chromatography columns connected in series.

[0015] Preferably, the eluent is one or more aqueous solutions of NaOH, KOH or LiOH.

[0016] Preferably, the pH of the eluent is between 8 and 12.

[0017] Preferably, the crude D-biotin to be separated is prepared by chemical synthesis, wherein the mass content of D-biotin in the crude D-biotin to be separated is 97.0-98.9%, and the mass content of L-biotin is 0.10-0.40%. The crude D-biotin to be separated is reacted with an alkaline solution of the same molar equivalent, and dissolved in water to form a salt solution with a concentration of 10-100 mg / mL, preferably 40-60 mg / mL.

[0018] The alkaline solution is one or more aqueous solutions of NaOH, KOH or LiOH, which are consistent with the alkali in the eluent.

[0019] Preferably, the injection flow rate is 0.05-0.80 mL / min, the elution flow rate is 1.00-10.00 mL / min, the extract flow rate is 0.45-6.50 mL / min, and the raffinate flow rate is 0.50-8.00 mL / min; further preferably, the injection flow rate is 0.10-0.50 mL / min, the elution flow rate is 1.20-6.50 mL / min, the extract flow rate is 0.50-3.50 mL / min, and the raffinate flow rate is 0.75-4.00 mL / min.

[0020] Preferably, the ratio of the injection flow rate to the elution flow rate is 1:10-20;

[0021] The ratio of the extraction liquid flow rate to the raffinate flow rate is 1:1.01-1.50.

[0022] Preferably, the feed point, eluent input point, extract withdrawal point and raffinate withdrawal point are switched to the next chromatographic column along the direction of mobile phase flow at regular intervals; the simulated moving bed chromatography is switched regularly for 10.0 to 30.0 minutes.

[0023] Preferably, the operating temperature of the simulated moving bed chromatography separation is 20-40°C.

[0024] Preferably, the high-purity D-biotin salt is pH-adjusted with dilute acid and filtered to further obtain high-purity D-biotin.

[0025] Compared with the prior art, the beneficial effects of the present invention are embodied in:

[0026] The present invention utilizes a simulated moving bed system, optimizing the use of inexpensive conventional stationary phases (achiral) and mobile phases to directly resolve biotin and obtain a high-purity D-biotin product. This avoids the extensive use and recovery of derivatizing agents, simplifies operational steps and procedures, and offers a simple process, low energy consumption, and stable product quality. The process can process large quantities, enabling continuous automated production and suitability for industrialized production. Furthermore, the process boasts high separation efficiency, low stationary phase and solvent consumption, and is environmentally friendly, with a D-biotin yield exceeding 96.00%. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the simulated moving bed chromatography separation of biotin enantiomers of the present invention;

[0028] Figure 2 This is a chromatogram of the crude D-biotin (SMB raw material) used in Example 1;

[0029] Figure 3 This is a chromatogram of the high-purity D-biotin product obtained in Example 1;

[0030] Figure 4 This is the chromatogram of the low-purity D-biotin product obtained in Example 1. DETAILED DESCRIPTION

[0031] Depend on Figure 1 As shown in the schematic diagram of the simulated moving bed chromatography for the separation of biotin enantiomers, the simulated moving bed chromatography is divided into four zones by a feed point (corresponding to the feed liquid flow rate Vf), an eluent input point (corresponding to the eluent flow rate Vd), an extract withdrawal point (corresponding to the extract flow rate Ve), and a raffinate withdrawal point (corresponding to the raffinate flow rate Vr). Each zone has 1 to 8 pillars, wherein zone I is between the eluent input point and the extract withdrawal point, where L-biotin salt is desorbed; zone II is located between the extract withdrawal point and the sample injection point, where L-biotin salt is repeatedly adsorbed, desorbed, and concentrated; and zone II is located between the extract withdrawal point and the sample injection point. Zone I is located between the injection point and the raffinate extraction point, and D-biotin salt solution is obtained in this zone; Zone IV is located between the raffinate extraction point and the eluent input point, separating Zone III from Zone I to prevent D-biotin salt in the raffinate from entering Zone I, while achieving regeneration and recycling of the eluent; a switching time Ts is given, and after Ts time, the feed point, eluent input point, extract extraction point, and raffinate extraction point are respectively switched to the next chromatographic column along the direction of mobile phase flow, and the stationary phase forms a virtual flow in the opposite direction of the mobile phase, thereby achieving a separation effect close to that of real moving bed chromatography.

[0032] Equipment and condition selection

[0033] A simulated moving bed chromatography system was used, consisting of an elution pump, a sample injection pump, an extraction pump, a raffinate pump, a chromatographic column, a pneumatic switching valve, a check valve, and a computer. The sample solution and eluent were injected into the system from the feed and eluent input points, respectively. The two enantiomers of biotin were discharged from the extract and raffinate withdrawal points, respectively. At a predetermined interval, Ts, the feed, eluent input, extract, and raffinate withdrawal points were switched to the next chromatographic column, along the direction of mobile phase flow.

[0034] Selection of column stationary phase and eluent

[0035] Monodisperse reverse phase polymer filler synthesized with polystyrene / divinylbenzene as the matrix.

[0036] The eluent is one of aqueous solutions of NaOH, KOH or LiOH with different concentrations.

[0037] Separation steps

[0038] A. Equal molar amounts of crude D-biotin react with an alkaline solution and dissolve into a salt solution with a concentration of 10-100 mg / mL. The simulated moving bed system consists of 4-32 chromatographic columns. A greater number of columns improves separation efficiency, but also increases system pressure and complexity. The preferred number of columns is 4-8. The entire simulated moving bed system is divided into four zones: the feed point, the eluent input point, the extract withdrawal point, and the raffinate withdrawal point. By controlling the opening and closing of pneumatic switching valves, the feed point, the eluent input point, the extract withdrawal point, and the raffinate withdrawal point are switched to the next chromatographic column along the mobile phase at regular intervals, thereby simulating backward movement of the stationary phase. High-purity D-biotin salt and low-purity D-biotin salt exit the system from the raffinate withdrawal point and the extract withdrawal point, respectively.

[0039] B. The obtained high-purity D-biotin salt product solution is first adjusted to pH 3 with dilute acid and then filtered to obtain a high-purity D-biotin product with a purity of more than 99.90%.

[0040] C. Finished product inspection

[0041] Mobile phase: pH = 3 phosphate buffer: acetonitrile = 90:10

[0042] Flow rate: 0.6 mL / min

[0043] Chromatographic column: CORESHELL column (4.6*100mm, 2.7μm)

[0044] Detection wavelength: 210nm

[0045] The present invention is further described below in conjunction with embodiments:

[0046] Example 1

[0047] 1. Sample preparation: Crude D-biotin (D-biotin content: 98.76%, L-biotin content: 0.32%) was reacted with an equal molar amount of NaOH and dissolved to form a salt solution. The solution was then prepared with deionized water to a concentration of 20 mg / mL. The solution was filtered through a 0.22 μm PES filter and set aside.

[0048] 2. Selection of simulated moving bed parameters: The parameters are determined as follows: The simulated moving bed system has a total of 4 chromatographic columns with specifications of Φ10mm*250mm. The numbers of chromatographic columns in the four zones are 1, 1, 1, and 1 respectively. The stationary phase is a monodisperse reversed-phase polymer filler PolyRP-100 synthesized with polystyrene / divinylbenzene as the matrix, with an average particle size of 10μm and a uniformity coefficient of 1.1. The eluent is NaOH solution with a pH of 9, an injection flow rate of 0.10mL / min, an elution flow rate of 1.36mL / min, an extract flow rate of 0.70mL / min, a raffinate flow rate of 0.76mL / min, a switching time of 20.19min, and the temperature is controlled at 30℃.

[0049] 3. Product collection: After the simulated moving bed system runs stably, collect products from the two outlets respectively, adjust the pH to 3 with dilute hydrochloric acid, and obtain the final product after filtration.

[0050] 4. Finished product inspection: Liquid chromatography results of crude D-biotin (SMB raw material), high-purity D-biotin product and low-purity D-biotin product are as follows: Figure 2 、 Figure 3 and Figure 4 As shown, the D-biotin content of the raffinate outlet product is 2.57 mg / mL and the purity is 99.92%.

[0051] Each kilogram of stationary phase can produce 0.14 kg of D-biotin per day, the mobile phase consumption is 95.83 L / (kg.d), and the recovery rate is 98.89%.

[0052] The above recovery rate Among them, m R,D -Biotin---Mass of product D-biotin in the raffinate, mg; m F,D -Biotin---Mass of product D-biotin in feed, mg; Q R ---Raffinate flow rate, mL / min; Q F ---Injection flow rate, mL / min; C R,D -Biotin---Average content of product D-biotin in the raffinate, mg / mL; C F,D -Biotin---D-biotin content in the feed, mg / mL.

[0053] Example 2

[0054] 1. Sample preparation: Crude D-biotin (D-biotin content: 98.58%, L-biotin content: 0.29%) was reacted with an equal molar amount of KOH and dissolved to form a salt solution. The solution was then prepared with deionized water to a concentration of 60 mg / mL and filtered through a 0.22 μm PES filter for later use.

[0055] 2. Selection of simulated moving bed parameters: The parameters are determined as follows: the simulated moving bed system has a total of 6 chromatographic columns with specifications of Φ20mm*250mm. The numbers of chromatographic columns in the four zones are 1, 2, 2, and 1 respectively. The stationary phase is a monodisperse reversed-phase polymer filler PolyRP-300 synthesized with polystyrene / divinylbenzene as the matrix, with an average particle size of 20μm and a uniformity coefficient of 1.1. The pH of the eluent KOH solution is 11, the injection flow rate is 0.47mL / min, the elution flow rate is 6.13mL / min, the extraction flow rate is 3.17mL / min, the raffinate flow rate is 3.44mL / min, the switching time is 17.32min, and the temperature is controlled at 35℃.

[0056] 3. Product collection: After the simulated moving bed system runs stably, collect products from the two outlets respectively, adjust the pH to 3 with dilute acid, and obtain the final product after filtration.

[0057] 4. Finished product inspection: The D-biotin content of the raffinate export product was detected using analytical conditions and was 7.91 mg / mL, with a purity of 99.86%.

[0058] Each kilogram of stationary phase can produce 0.25 kg of D-biotin per day, the mobile phase consumption is 54.10 L / (kg.d), and the recovery rate is 97.88%.

[0059] Example 3

[0060] 1. Sample preparation: Crude D-biotin (D-biotin content: 98.54%, L-biotin content: 0.27%) was reacted with an equal molar amount of LiOH and dissolved to form a salt solution. The solution was prepared with deionized water to a concentration of 50 mg / mL and filtered through a 0.22 μm PES filter for later use.

[0061] 2. Selection of simulated moving bed parameters: The parameters are determined as follows: the simulated moving bed system has a total of 8 chromatographic columns with specifications of Φ10mm*250mm. The number of chromatographic columns in the four zones are 2, 2, 2, and 2 respectively. The stationary phase is a monodisperse reversed-phase polymer filler PolyRP-100 synthesized with polystyrene / divinylbenzene as the matrix, with an average particle size of 30μm and a uniformity coefficient of 1.2. The eluent LiOH solution has a pH of 10, an injection flow rate of 0.12mL / min, an elution flow rate of 1.67mL / min, an extract flow rate of 0.87mL / min, a raffinate flow rate of 0.92mL / min, a switching time of 15.9min, and the temperature is controlled at 35℃.

[0062] 3. Product collection: After the simulated moving bed system runs stably, collect products from the two outlets respectively, adjust the pH to 3 with dilute acid, and obtain the final product after filtration.

[0063] 4. Finished product inspection: The D-biotin content of the raffinate export product was detected using analytical conditions and was 6.20 mg / mL, with a purity of 99.86%.

[0064] Each kilogram of stationary phase can produce 0.20 kg of D-biotin per day, the mobile phase consumption is 58.94 L / (kg.d), and the recovery rate is 96.48%.

[0065] Example 4

[0066] 1. Sample preparation: Crude D-biotin (D-biotin content: 97.83%, L-biotin content: 0.34%) was reacted with an equal molar amount of NaOH and dissolved to form a salt solution. The solution was then prepared with deionized water to a concentration of 30 mg / mL and filtered through a 0.22 μm PES filter for later use.

[0067] 2. Selection of simulated moving bed parameters: The parameters are as follows: The simulated moving bed system has 8 chromatographic columns with specifications of Φ10mm*250mm. The number of chromatographic columns in the four zones are 1, 3, 3, and 1 respectively. The stationary phase filler is Amberchrom TM XT-30 macroporous polymer reverse phase packing, average particle size of 30 μm, uniformity coefficient of 1.25, eluent NaOH solution pH 11, injection flow rate 0.13 mL / min, elution flow rate 1.98 mL / min, extraction flow rate 1.01 mL / min, raffinate flow rate 1.10 mL / min, switching time 13.82 min, temperature controlled at 30 °C.

[0068] 3. Product collection: After the simulated moving bed system runs stably, collect the products from the two outlets respectively, adjust the pH to 3 with dilute acid, and obtain the final product after filtration;

[0069] 4. Finished product inspection: The D-biotin content of the raffinate export product was tested under analytical conditions and was 3.39 mg / mL, with a purity of 99.87%;

[0070] Each kilogram of stationary phase can produce 0.13 kg of D-biotin per day, the mobile phase consumption is 69.99 L / (kg.d), and the recovery rate is 97.74%.

[0071] Example 5

[0072] 1. Sample preparation: Crude D-biotin (D-biotin content: 98.23%, L-biotin content: 0.30%) was reacted with an equal molar amount of NaOH and dissolved to form a salt solution. The solution was prepared with deionized water to a concentration of 20 mg / mL and filtered through a 0.22 μm PES filter membrane before use.

[0073] 2. Selection of simulated moving bed parameters: The parameters are as follows: The simulated moving bed system has 4 chromatographic columns with specifications of Φ20mm*250mm. The number of chromatographic columns in the four zones is 1, 1, 1, and 1 respectively. The stationary phase filler is Amberchrom TM The XT-20 macroporous polymer reverse phase packing had an average particle size of 20 μm, a uniformity coefficient of 1.2, an eluent NaOH solution with a pH of 8, an injection flow rate of 0.42 mL / min, an elution flow rate of 4.97 mL / min, an extract flow rate of 2.66 mL / min, a raffinate flow rate of 2.73 mL / min, a switching time of 22.76 min, and the temperature was controlled at 30°C.

[0074] 3. Product collection: After the simulated moving bed system runs stably, collect the products from the two outlets respectively, adjust the pH to 3 with dilute acid, and obtain the final product after filtration;

[0075] 4. Finished product inspection: The D-biotin content of the raffinate export product was tested under analytical conditions and was 2.97 mg / mL, with a purity of 99.82%;

[0076] Each kilogram of stationary phase can produce 0.15 kg of D-biotin per day, the mobile phase consumption is 87.61 L / (kg.d), and the recovery rate is 98.26%.

[0077] Comparative Example 1

[0078] 1. Sample preparation: Crude D-biotin (D-biotin content: 98.54%, L-biotin content: 0.27%) was reacted with an equal molar amount of NaOH solution and dissolved to form a salt solution. The solution was prepared with deionized water to a concentration of 50 mg / mL and filtered through a 0.22 μm PES filter membrane before use.

[0079] 2. Selection of simulated moving bed parameters: The parameters are determined as follows: The simulated moving bed system has a total of 8 chromatographic columns with specifications of Φ10mm*250mm. The number of chromatographic columns in the four zones are 2, 2, 2, and 2 respectively. The stationary phase is a monodisperse reversed-phase polymer filler PolyRP-100 synthesized with polystyrene / divinylbenzene as the matrix, with an average particle size of 30μm and a uniformity coefficient of 1.2. The pH of the eluent NaOH solution is 10, the injection flow rate is 0.09mL / min, the elution flow rate is 0.92mL / min, the extraction flow rate is 0.41mL / min, the raffinate flow rate is 0.60mL / min, the switching time is 26.60min, and the temperature is controlled at 35℃.

[0080] 3. Product collection: After the simulated moving bed system is running stably, products are collected from the two outlets respectively. The purity of the D-biotin product of the raffinate outlet is 98.76% when tested under analytical conditions.

[0081] The above results show that incorrect parameters cannot effectively remove L-biotin and cannot produce a high-purity D-biotin product with a purity of more than 99.90% through crystallization.

[0082] Comparative Example 2

[0083] 1. Sample preparation: Crude D-biotin (D-biotin content: 98.54%, L-biotin content: 0.27%) was reacted with an equal molar amount of NaOH solution and dissolved to form a salt solution. The solution was then prepared with deionized water to a concentration of 50 mg / mL and filtered through a 0.22 μm PES filter for later use.

[0084] 2. Selection of simulated moving bed parameters: The parameters are determined as follows: the simulated moving bed system has a total of 8 chromatographic columns with specifications of Φ20mm*250mm. The numbers of chromatographic columns in the four zones are 1, 3, 3, and 1 respectively. The stationary phase filler is AMBERCHROM 50W×2 strongly acidic cation exchange resin (sodium type), with an average particle size of 50μm and a uniformity coefficient of 1.2. The pH of the eluent NaOH solution is 11, the injection flow rate is 0.43mL / min, the elution flow rate is 5.62mL / min, the extraction flow rate is 2.91mL / min, the raffinate flow rate is 3.14mL / min, the switching time is 18.90min, and the temperature is controlled at 35℃.

[0085] 3. Product collection: After the simulated moving bed system is running stably, products are collected from the two outlets respectively. The purity of the D-biotin product of the raffinate outlet is 98.54% when tested under analytical conditions.

[0086] The above results show that an inappropriate stationary phase filler cannot effectively remove L-biotin and cannot obtain a high-purity D-biotin product with a purity of more than 99.90% through crystallization.

Claims

1. A method for resolving biotin enantiomers using simulated moving bed chromatography, characterized in that: include: A salt solution of crude D-biotin to be separated is injected into the feed point of the simulated moving bed chromatography, an eluent is injected into the eluent input point of the simulated moving bed chromatography, and a high-purity D-biotin salt and a low-purity D-biotin salt are obtained from the raffinate extraction point and the extract extraction point of the simulated moving bed chromatography, respectively; The stationary phase of the simulated moving bed chromatography is a polystyrene / divinylbenzene type reverse phase polymer filler with a particle size range of 5 to 50 μm and a uniformity coefficient of 1.0 to 1.3; The eluent is an alkaline aqueous solution.

2. The method for resolving biotin enantiomers using simulated moving bed chromatography according to claim 1, wherein: The simulated moving bed chromatography is composed of 4 to 32 identical chromatography columns connected in series.

3. The method for resolving biotin enantiomers using simulated moving bed chromatography according to claim 1, wherein: The eluent is one or more aqueous solutions of NaOH, KOH, and LiOH.

4. The method for resolving biotin enantiomers using simulated moving bed chromatography according to claim 1 or 3, characterized in that: The pH value of the eluent is 8-12.

5. The method for resolving biotin enantiomers using simulated moving bed chromatography according to claim 1, wherein: The crude D-biotin product to be separated has a D-biotin content of 97.0 to 98.9% by mass and an L-biotin content of 0.10 to 0.40% by mass; The salt solution is obtained by reacting and dissolving crude D-biotin with an alkali solution of the same molar equivalent, and the concentration is 10-100 mg / mL, preferably 40-60 mg / mL; the alkali solution is one or more aqueous solutions of NaOH, KOH, and LiOH.

6. The method for resolving biotin enantiomers using simulated moving bed chromatography according to claim 1, wherein: The injection flow rate is 0.05-0.80 mL / min, the elution flow rate is 1.00-10.00 mL / min, the extraction flow rate is 0.45-6.50 mL / min, and the raffinate flow rate is 0.50-8.00 mL / min.

7. The method for resolving biotin enantiomers using simulated moving bed chromatography according to claim 1 or 6, characterized in that: The ratio of the injection flow rate to the elution flow rate is 1:8-20; The ratio of the extraction liquid flow rate to the raffinate flow rate is 1:1.01-1.

50.

8. The method for resolving biotin enantiomers using simulated moving bed chromatography according to claim 1, wherein: At regular intervals, the feed point, eluent input point, extract withdrawal point, and raffinate withdrawal point are switched to the next chromatographic column along the direction of mobile phase flow; The simulated moving bed chromatography is periodically switched for a period of 10.0 to 30.0 minutes.

9. The method for resolving biotin enantiomers using simulated moving bed chromatography according to claim 1, wherein: The operating temperature of the simulated moving bed chromatographic separation is 20-40°C.

10. The method for resolving biotin enantiomers using simulated moving bed chromatography according to claim 1, wherein: The high-purity D-biotin salt is further purified by adjusting the pH with dilute acid and filtering.

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