A chromatographic stationary phase embedded with aminocarbamoylhydrazide groups and its preparation method

Abstract

The present invention discloses a chromatographic stationary phase embedded with a carbamoylhydrazide group and a preparation method thereof. Using a carbamoylhydrazide technology, a silane bearing a carbamoylhydrazide group is first obtained. The silane is then bonded to porous silica gel, and finally, the silica gel is tail-capped with a tail-capping agent to produce a novel chromatographic stationary phase embedded with a carbamoylhydrazide group. The chromatographic stationary phase embedded with a carbamoylhydrazide group prepared by the present invention has a novel structure and a wide range of applications. The embedded polar group improves the hydrophilicity of the long-chain alkyl group and reduces the tailing factor of polar compounds, particularly alkaline compounds. Furthermore, the phase exhibits good separation selectivity for most polar and non-polar compounds.

Description

Technical Field

[0001] The invention belongs to the technical field of high performance liquid chromatography filling materials, and particularly relates to a chromatographic stationary phase embedded with a carbamoyl hydrazide group and a preparation method thereof. Background Art

[0002] High-performance liquid chromatography (HPLC), as an important analytical method, is currently widely used in various fields such as biology, medicine, industry, agriculture, and chemistry. As the core component of HPLC systems, the development of chromatographic stationary phases has profoundly influenced the development of HPLC. Among them, alkyl-bonded stationary phases occupy a major position in modern reversed-phase chromatographic stationary phases. They have advantages such as good chemical inertness and stability, and their preparation process is very mature. Alkyl-bonded stationary phases often use porous silica spheres as carriers and alkyl chains as bonding phases, such as octadecyl (C18), docosyl (C22), and triacontyl (C30). They have a simple chromatographic retention mechanism and exhibit good separation selectivity for most lipophilic compounds.

[0003] Liquid chromatography stationary phases with polar functional groups embedded in alkyl chains were introduced in the early 1990s. One of their key advantages is the reduction of secondary interactions between free silyl groups on the packing surface and basic analytes, thereby improving peak shape for basic compounds. This type of packing differs significantly from conventional reversed-phase packings in that it contains a hydrophilic group. While the hydrophobic interactions of polar embedded stationary phases are weaker than those of corresponding alkyl stationary phases, they can provide more interactions, such as hydrogen bonding, for complex analytes, potentially improving separations in complex matrices.

[0004] Currently, a large number of polar groups have been introduced into the roots or side chains of the alkyl chains on the surface of silica gel, such as amino groups, amide groups, ether groups, urea groups, etc. These groups can increase different forces, not only enhancing the hydrophilicity of the stationary phase, but also protecting alkaline compounds from secondary reactions with dissociated silanol groups under acidic or neutral conditions. Therefore, they have a certain shielding effect on silanol groups, thereby improving the separation of alkaline compounds. However, due to the limited shielding effect of the embedded polar groups, the residual silanol groups still have secondary reactions with the alkaline analytes, causing tailing of the chromatographic peaks of the alkaline compounds, affecting the separation degree and separation efficiency. Therefore, the development of a new type of polar group chromatographic stationary phase with a stronger silanol shielding effect is expected to further improve the separation of alkaline compounds.

[0005] From a chemical perspective, carbamoylhydrazide is equivalent to an amide / hydrazide hybrid, exhibiting excellent stability and hydrophilicity. Embedding carbamoylhydrazide groups into fillers also inherits the various properties of this group, such as hydrogen bond donor-acceptor interactions and carbonyl-carbonyl affinity, potentially resulting in better separation of samples with complex structures and diverse compositions. Furthermore, chromatographic stationary phases embedded with carbamoylhydrazide groups would enrich the variety of reversed-phase chromatographic stationary phases, broaden their scope of application, and provide more options for the analysis and separation of compounds. Given these facts, the development of a chromatographic stationary phase embedded with carbamoylhydrazide groups is highly significant. Summary of the Invention

[0006] The present invention aims to provide a novel chromatographic stationary phase embedded with carbamoylhydrazide groups and a method for preparing the same. The chromatographic stationary phase embedded with carbamoylhydrazide groups provided by the present invention has a novel structure. By embedding polar groups, the hydrophilicity of long-chain alkyl groups is improved, the tailing factor of polar compounds, particularly alkaline compounds, is reduced, and good separation selectivity is achieved for most polar and non-polar compounds.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a novel chromatographic stationary phase embedded with a carbamoylhydrazide group, wherein the chromatographic stationary phase embedded with a carbamoylhydrazide group has the following structure:

[0009]

[0010] In the structural formula, R is any one of an aliphatic hydrocarbon group and an aromatic hydrocarbon group.

[0011] In a second aspect, the present invention provides a method for preparing a novel chromatographic stationary phase embedded with a carbamoylhydrazide group, the preparation method comprising the following steps:

[0012] A. dissolving hydrazide in aromatic hydrocarbon, and adding isocyanate silane dropwise to the aromatic hydrocarbon containing hydrazide to obtain a reaction solution containing carbamoyl hydrazide silane;

[0013] B. reacting the reaction solution containing carbamoyl hydrazide silane obtained in step A with silica gel to obtain a bonded silica gel chromatographic stationary phase;

[0014] C. Add a capping agent to the bonded silica gel chromatographic stationary phase prepared in step B for capping to obtain a chromatographic stationary phase embedded with aminocarbamoyl hydrazide groups.

[0015] Step A is specifically as follows: dissolving hydrazide in aromatic hydrocarbon, heating to 70-90° C., adding isocyanate silane dropwise, maintaining the temperature constant and continuing the reaction for 4-6 hours to obtain a reaction solution containing carbamoyl hydrazide silane.

[0016] Step B is specifically as follows: dissolving porous silica gel in aromatic hydrocarbon, heating to 110-145° C., maintaining the temperature constant and reflux for 20-30 hours, then adding the reaction solution containing aminocarbamoyl hydrazide silane prepared in step A, reflux for 20-30 hours, filtering to remove the solvent, and then washing with aromatic hydrocarbon, ethanol, methanol and acetone in sequence, and drying to obtain a bonded silica gel chromatographic stationary phase.

[0017] Step C specifically comprises: placing the bonded silica gel chromatographic stationary phase prepared in step B in aromatic hydrocarbon, heating to 100-110° C., dripping a tailing agent for 1-2 hours, continuing the reaction for 12-24 hours after the dripping is completed, filtering to remove the solvent, and then washing with aromatic hydrocarbon, ethanol, methanol and acetone in sequence to obtain a chromatographic stationary phase embedded with aminocarbamoyl hydrazide groups.

[0018] In the step A, the molar ratio of hydrazide to isocyanate silane is 1:0.95-0.99.

[0019] The aromatic hydrocarbon in steps A, B and C is toluene, xylene, ethylbenzene or benzene.

[0020] In the step A, the hydrazide includes aliphatic hydrazide and aromatic hydrazide.

[0021] In step A, the isocyanate silane conforms to the following general formula: wherein n is any natural number not less than 2, and X is at least one alkoxy group.

[0022] In the step C, the tail-sealing agent is hexamethyldisilazane or trimethylchlorosilane.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. Novel structure: The present invention proposes a reversed-phase chromatographic stationary phase containing a novel polar embedded group, wherein the stationary phase structure contains aminocarbamoylhydrazide.

[0025] 2. Wide range of applications: The embedding of polar groups improves the hydrophilicity of long-chain alkyl groups and reduces the tailing factor of polar compounds, especially alkaline compounds, and has good separation selectivity for most polar and non-polar compounds. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The figure shows the preparation flow chart of a chromatographic stationary phase embedded with aminocarbamoylhydrazide groups.

[0027] Figure 2 The chromatographic separation diagram of basic tricyclic antidepressants on 18-aminocarboxamidohydrazide bonded chromatographic stationary phase and C18 chromatographic stationary phase.

[0028] Figure 3 The chromatographic separation diagrams of uracil, benzene, naphthalene and fluorene on 18-aminocarbohydrazide silane chromatographic stationary phase from different batches.

[0029] Figure 4 The chromatographic separation diagrams of propranolol and amitriptyline on different batches of octadecylcarbamate silane chromatographic stationary phase. DETAILED DESCRIPTION

[0030] In order to enable researchers in this field to better understand the present invention, specific embodiments are described in detail.

[0031] Example 1: Octadecaaminoformylhydrazide chromatographic stationary phase and preparation method thereof

[0032] This embodiment provides an octadecylcarbamoylhydrazide chromatographic stationary phase, wherein the octadecylcarbamoylhydrazide chromatographic stationary phase has the following structure:

[0033]

[0034] The preparation method of the octaaminocarbamoylhydrazide chromatographic stationary phase comprises the following three steps A, B, and C in sequence:

[0035] A. 5.97 g of octadecanoylhydrazide was dissolved in 40 mL of toluene. After heating to 75°C, 4.05 g of 3-isocyanatepropyltrimethoxysilane was added dropwise. The temperature was maintained constant and the reaction was continued for 4 h to obtain a reaction solution containing octadecanoylcarbamoylhydrazide silane.

[0036] B. 15 g of fully porous spherical silica gel (diameter 10 μm, specific surface area 350 m 2 g -1 ) was dissolved in 90 mL of toluene, heated to 110°C, and refluxed for 20 hours. The reaction solution containing octadecylcarbamoyl hydrazide silane obtained in step A was then added all at once to the toluene solution containing silica gel and refluxed for 24 hours. The solvent was removed by filtration, and the mixture was then washed thoroughly with toluene, ethanol, methanol, and acetone, followed by drying to obtain a bonded silica gel stationary phase.

[0037] C. Place the bonded silica gel stationary phase in B in 90 mL of toluene and heat to 100°C. Then add 1.27 g of hexamethyldisilazane over 1 hour. After the addition is complete, reflux for 12 hours. Filter to remove the solvent, and then wash thoroughly with toluene, ethanol, methanol, and acetone in sequence to obtain 18-aminoformamide hydrazide chromatographic stationary phase.

[0038] Organic element analysis showed that the carbon content of the stationary phase was 17.67% and the nitrogen content was 2.37%.

[0039] Example 2: 2-Diaminoformylhydrazide Chromatographic Stationary Phase and Preparation Method

[0040] This embodiment provides a 22-aminoformylhydrazide chromatographic stationary phase, wherein the 22-aminoformylhydrazide chromatographic stationary phase has the following structure:

[0041]

[0042] The preparation method of the described 22-aminoformylhydrazide chromatographic stationary phase comprises the following three steps A, B, and C in sequence:

[0043] A. 14.16 g of behenyl hydrazide was azeotropically dehydrated in 70 mL of xylene, and the temperature was raised to 80° C. Then 9.10 g of 3-isocyanatepropyltrimethoxysilane was added dropwise thereto. The temperature was maintained constant and the reaction was continued for 5 h to obtain a reaction solution of behenyl carbamoyl hydrazide silane.

[0044] B. 30 g of fully porous spherical silica gel (diameter 10 μm, specific surface area 350 m 2 g -1 ) was dissolved in 180 mL of xylene, heated to 140°C, and kept at constant temperature for 24 h. The reaction solution of the di-dodecylaminoformyl hydrazide silane obtained in step A was added into the benzene solution containing silica gel at one time, and refluxed for 24 h. The solvent was filtered to remove the solvent, and then washed with benzene, ethanol, methanol and acetone in sequence, and dried to obtain a bonded silica gel stationary phase.

[0045] C. Place the silica gel product in B in 180 mL of xylene and heat to 105°C. Then, add 2.54 g of hexamethyldisilazane dropwise for 1.5 hours. After the addition is complete, reflux for 18 hours. Filter to remove the solvent, and then wash with toluene, ethanol, methanol, and acetone in sequence to obtain the di-2-aminocarboxamide chromatographic stationary phase.

[0046] Organic element analysis showed that the carbon content of the stationary phase was 20.1% and the nitrogen content was 1.89%.

[0047] Example 3: Benzylaminocarbamoyl hydrazide chromatographic stationary phase and preparation method thereof

[0048] This embodiment provides a benzylaminocarboxamide chromatographic stationary phase, wherein the benzylaminocarboxamide chromatographic stationary phase has the following structure:

[0049]

[0050] The preparation method of the benzylaminocarboxamide chromatographic stationary phase comprises the following three steps A, B, and C in sequence:

[0051] 3.44 g of A benzoylhydrazide was dissolved in 40 mL of toluene. After heating to 75°C, 4.05 g of 3-isocyanatepropyltrimethoxysilane was added dropwise. The temperature was kept constant and the reaction was continued for 4.5 h to obtain a reaction solution containing benzoylaminohydrazide silane.

[0052] B. 15 g of fully porous spherical silica gel (diameter 10 μm, specific surface area 350 m 2 g -1 ) in 90 mL of toluene, heat to 115°C, and maintain reflux for 20 hours. Then, add the reaction solution containing phenylmethylaminoformyl hydrazide silane obtained in step A all at once to the toluene solution containing silica gel and reflux for 24 hours. Filter to remove the solvent, then wash thoroughly with toluene, ethanol, methanol, and acetone, followed by drying to obtain a bonded silica gel stationary phase.

[0053] C. Place the bonded silica gel stationary phase in B in 90 mL of toluene and heat to 110°C. Then add 1.27 g of hexamethyldisilazane over 1 hour. After the addition is complete, reflux for 16 hours. Filter to remove the solvent, and then wash thoroughly with toluene, ethanol, methanol, and acetone in sequence to obtain the benzylaminocarboxamide chromatographic stationary phase.

[0054] Organic element analysis showed that the carbon content of the stationary phase was 15.43% and the nitrogen content was 4.21%.

Claims

1. A chromatographic stationary phase embedded with a carbamoyl hydrazide group, characterized in that The chromatographic stationary phase embedded with aminocarbamoylhydrazide groups has the following structural formula: In the structural formula, R is any one of an aliphatic hydrocarbon group and an aromatic hydrocarbon group.

2. A method for preparing the chromatographic stationary phase embedded with carbamoyl hydrazide groups according to claim 1, characterized in that: The preparation method comprises the following steps: A. dissolving hydrazide in aromatic hydrocarbon, and then adding isocyanate silane dropwise to the aromatic hydrocarbon containing hydrazide to obtain a reaction solution containing carbamoyl hydrazide silane; B. reacting the reaction solution containing carbamoyl hydrazide silane obtained in step A with silica gel to obtain a bonded silica gel chromatographic stationary phase; C. Add a capping agent to the bonded silica gel chromatographic stationary phase prepared in step B for capping to obtain a chromatographic stationary phase embedded with aminocarbamoyl hydrazide groups.

3. The preparation method according to claim 2, wherein The step A specifically comprises: dissolving hydrazide in aromatic hydrocarbon, heating to 70-90° C., adding isocyanate silane dropwise, maintaining the temperature constant and continuing the reaction for 4-6 hours to obtain a reaction solution containing carbamoyl hydrazide silane.

4. The preparation method according to claim 2, characterized in that The step B specifically comprises: dissolving porous silica gel in aromatic hydrocarbon, heating to 110-145° C., maintaining the temperature and refluxing for 20-30 hours, then adding the reaction solution containing aminocarbamoyl hydrazide silane prepared in step A, refluxing for 20-30 hours, filtering to remove the solvent, and then washing with aromatic hydrocarbon, ethanol, methanol and acetone in sequence, and drying to obtain a bonded silica gel chromatographic stationary phase.

5. The preparation method according to claim 2, characterized in that The step C specifically comprises: placing the bonded silica gel chromatographic stationary phase prepared in step B in aromatic hydrocarbon, heating to 100-110° C., dripping a tailing agent for 1-2 hours, continuing the reaction for 12-24 hours after the dripping is complete, filtering to remove the solvent, and then washing with aromatic hydrocarbon, ethanol, methanol and acetone in sequence to obtain a chromatographic stationary phase embedded with a carbamoyl hydrazide group.

6. The method according to claim 2 or 3, characterized in that: The molar ratio of hydrazide to isocyanate silane is 1:0.95-0.

99.

7. The method according to any one of claims 2 to 5, characterized in that: The aromatic hydrocarbon is toluene, xylene, ethylbenzene or benzene.

8. The method according to claim 2 or 3, characterized in that: The hydrazide includes an aliphatic hydrazide or an aromatic hydrazide.

9. The method according to claim 2 or 5, characterized in that: The tail-sealing agent is hexamethyldisilazane or trimethylchlorosilane.

Images