阅读说明：本技术 一种微孔聚合物聚多巴胺复合材料固相微萃取探针及其制备方法与应用 (Microporous polymer polydopamine composite solid-phase microextraction probe and preparation method and application thereof ) 是由 刘舒芹 向章敏 方舒婷 于 2020-04-20 设计创作，主要内容包括：本发明公开了一种微孔聚合物聚多巴胺复合材料固相微萃取探针及其制备方法与应用。所述固相微萃取探针包括不锈钢丝和涂覆于不锈钢丝上的表面涂层,所述表面涂层含有微孔聚合物/聚多巴胺复合材料,所述复合材料通过一种微孔聚合物的选择性孔内聚多巴胺修饰策略合成得到。本发明所述的微孔聚合物/聚多巴胺复合材料具有单一微孔分布、表面可被水浸润、对亲水性化合物具有增强的吸附性能、以及能够高效捕集多种性质不同的分析物的优点。本发明提供的微孔聚合物/聚多巴胺复合材料固相微萃取探针与商品化固相微萃取探针相比,对挥发性污染物具有更好的富集性能。(The invention discloses a solid-phase microextraction probe made of a microporous polymer polydopamine composite material, and a preparation method and application thereof. The solid-phase microextraction probe comprises a stainless steel wire and a surface coating coated on the stainless steel wire, wherein the surface coating contains a microporous polymer/polydopamine composite material, and the composite material is synthesized by a selective in-hole polydopamine modification strategy of a microporous polymer. The microporous polymer/polydopamine composite material has the advantages of single micropore distribution, water-wettable surface, enhanced adsorption performance on hydrophilic compounds and capability of efficiently trapping various analytes with different properties. Compared with a commercial solid phase microextraction probe, the microporous polymer/polydopamine composite solid phase microextraction probe provided by the invention has better enrichment performance on volatile pollutants.)

1. A microporous polymer/polydopamine composite solid phase microextraction probe is characterized in that a surface coating of the solid phase microextraction probe is a microporous polymer/polydopamine composite, and the composite is synthesized by a dopamine modification strategy in selective pores of a microporous polymer.

2. The microporous polymer/polydopamine composite solid-phase microextraction probe according to claim 1, wherein the length of the surface coating is 1-2 cm, and the thickness is 5-50 μm.

3. A method for preparing the microporous polymer/polydopamine composite solid phase microextraction probe according to claim 1 or 2, characterized by comprising the following steps:

s1: under the protection of nitrogen, adding anhydrous FeCl₃As a catalyst, adding dimethoxymethane as an external cross-linking agent, taking 1,3, 5-triphenylbenzene as a polymerization monomer, completing primary cross-linking and hypercrosslinking reactions at different temperatures by alkylation reaction under the stirring and heating states, synthesizing a microporous polymer with bimodal micropore distribution, collecting and washing a product after the reaction is completed, and drying to obtain the microporous polymer;

s2: uniformly mixing a microporous polymer with bimodal micropore distribution, dopamine hydrochloride, a trihydroxymethyl aminomethane buffer solution and ultrapure water under a stirring state, carrying out self-polymerization reaction on dopamine selectively on the surface of the microporous polymer and in smaller pores, centrifugally collecting a product after the reaction is finished, and drying to obtain the microporous polymer/polydopamine composite material;

s3: and (3) stretching the stainless steel wire into the adhesive solution, taking out and sucking the adhesive solution on the surface of the stainless steel wire, uniformly coating the microporous polymer/polydopamine composite material on the surface of the stainless steel wire, drying, repeating the steps for a plurality of times to ensure that the thickness of the coating meets the requirement, and finally aging in an inert gas atmosphere to obtain the solid-phase micro-extraction probe.

4. The method according to claim 3, wherein in step S1, the anhydrous FeCl is₃And dimethoxyThe mass ratio of the methane to the 1,3, 5-triphenylbenzene is (4-6) to (2-3) to (1-2); the primary crosslinking reaction temperature is 40-50 ℃, and the reaction time is 4-6 h; the hypercrosslinking reaction temperature is 60-100 ℃, and the reaction time is 18-30 h.

5. The method according to claim 3, wherein in step S2, the mass ratio of the microporous polymer to the dopamine hydrochloride is (8-12) to (3-5).

6. The method according to claim 3, wherein in step S2, the concentration of the buffer solution of tris is 8-12 mM, the pH value is 7-10, and the volume ratio of the buffer solution of tris to the ultrapure water is (3-5): (14-18).

7. The method according to claim 3,5 or 6, wherein in step S2, the mixing ratio of the total mass of the microporous polymer and the dopamine hydrochloride to the total volume of the tris buffer solution and the ultrapure water is 11-17 g/34-46 mL.

8. The method according to claim 3, wherein in step S2, the reaction temperature is room temperature and the reaction time is 18-30 h.

9. The method according to claim 3, wherein in step S3, the adhesive solution is a silicone adhesive/o-xylene solution, and the mass concentration of the silicone adhesive in the silicone adhesive/o-xylene solution is 0.2-0.8 g/mL.

10. Use of the microporous polymer/polydopamine composite solid phase microextraction probe of claim 1 or 2 for enrichment detection of volatile contaminants.

Technical Field

The invention relates to the technical field of material modification and solid-phase microextraction of microporous polymers, in particular to a selective in-pore polydopamine modification strategy of a microporous polymer, a microporous polymer/polydopamine composite material solid-phase microextraction probe, and a preparation method and application thereof.

Background

Solid-phase microextraction (SPME) is a technology which is simple and convenient to operate, does not need extraction and enrichment of a large amount of solvents, and can be used together with efficient analysis and detection means such as chromatography, electrophoresis, mass spectrometry and the like. Because of the advantages of small extraction amount, small interference to the system, easy automation and the like, the method is widely applied to the fields of environment, food, biomedicine and the like. Extractive coatings are the core of the SPME technology, which relies on the development and preparation of coating materials for its wide application and high sensitivity. Although some coatings have been commercialized, the commercial probes have the disadvantages of high price (800-. Therefore, it is necessary to provide a SPME probe material with strong broad-spectrum extraction performance, high capture efficiency of non-target pollutants, and low cost. The microporous polymer shows huge application potential in the field of SPME probe preparation due to the stability, high specific surface area and strong enrichment capacity. However, microporous polymers having high surface area and high pore volume have an inherent structure that is mostly hydrophobic, and thus have good adsorption selectivity to hydrophobic compounds and poor adsorption affinity to hydrophilic compounds. Under the background, a modification strategy is explored, and the important significance of improving the adsorption affinity of the material to the hydrophilic compound is achieved on the premise that the capture capacity of the microporous polymer material to the hydrophobic compound is not influenced remarkably.

Disclosure of Invention

The invention aims to provide a microporous polymer/polydopamine composite material synthesized by a selective pore coherent dopamine modification strategy of a microporous polymer, which can enhance the hydrophobic-hydrophilic balance performance of the microporous polymer and the broad-spectrum efficient adsorption performance of the microporous polymer on hydrophobic and hydrophilic substances.

The invention also aims to provide a solid phase microextraction probe of the microporous polymer/polydopamine composite material and a preparation method thereof.

The invention further aims to provide an application of the microporous polymer/polydopamine composite solid-phase microextraction probe in enrichment detection of volatile pollutants.

In order to achieve the purpose, the invention adopts the following technical scheme:

a microporous polymer/polydopamine composite solid-phase microextraction probe is characterized in that a surface coating of the microporous polymer/polydopamine composite solid-phase microextraction probe is a microporous polymer/polydopamine composite, and the composite is synthesized by a dopamine modification strategy in selective pores of a microporous polymer. Preferably, the length of the surface coating is 1-2 cm, and the thickness of the surface coating is 5-50 μm.

Specifically, the microporous polymer/polydopamine composite solid-phase microextraction probe is prepared by the following method, and the preparation method comprises the following steps:

s1: under the protection of nitrogen, adding anhydrous FeCl₃As a catalyst, adding dimethoxymethane as an external cross-linking agent, taking 1,3, 5-triphenylbenzene as a polymerization monomer, completing primary cross-linking and hypercrosslinking reactions at different temperatures by alkylation reaction under the stirring and heating states, synthesizing a microporous polymer with bimodal micropore distribution, collecting and washing a product after the reaction is completed, and drying to obtain the microporous polymer;

s2: uniformly mixing a microporous polymer with bimodal micropore distribution, dopamine hydrochloride, a trihydroxymethyl aminomethane buffer solution and ultrapure water under a stirring state, carrying out self-polymerization reaction on dopamine selectively on the surface of the microporous polymer and in smaller pores, centrifugally collecting a product after the reaction is finished, and drying to obtain the microporous polymer/polydopamine composite material;

s3: and (3) stretching the stainless steel wire into the adhesive solution, taking out and sucking the adhesive solution on the surface of the stainless steel wire, uniformly coating the microporous polymer/polydopamine composite material on the surface of the stainless steel wire, drying, repeating the steps for a plurality of times to ensure that the thickness of the coating meets the requirement, and finally aging in an inert gas atmosphere to obtain the solid-phase micro-extraction probe.

Preferably, in step S1, the anhydrous FeCl is₃The mass ratio of the dimethoxymethane to the 1,3, 5-triphenylbenzene is (4-6) to (2-3) to (1-2); the primary crosslinking reaction temperature is 40-50 ℃, and the reaction time is 4-6 h; the hypercrosslinking reaction temperature is 60-100 ℃, and the reaction time is 18-30 h. More preferably, the anhydrous FeCl₃The mass ratio of the dimethoxymethane to the 1,3, 5-triphenylbenzene is 4.87:2.29: 1.53; the primary crosslinking reaction temperature is 45 ℃, and the reaction time is 5 hours; the reaction temperature of the hypercrosslinking is 80 ℃, and the reaction time is 24 h.

Preferably, in step S2, the mass ratio of the microporous polymer to the dopamine hydrochloride is (8-12): (3-5). The concentration of the trihydroxymethyl aminomethane buffer solution is 8-12 mM, the pH value is 7-10, and the volume ratio of the trihydroxymethyl aminomethane buffer solution to the ultrapure water is (3-5): 14-18). The mixing ratio of the total mass of the microporous polymer and the dopamine hydrochloride to the total volume of the tris buffer solution and the ultrapure water is 11-17 g/34-46 mL. The reaction temperature is room temperature, and the reaction time is 18-30 h.

More preferably, in step S2, the mass ratio of the microporous polymer to the dopamine hydrochloride is 10: 4. The concentration of the tris buffer solution is 10mM, the pH value is 8.5, and the volume ratio of the tris buffer solution to the ultrapure water is 4: 16. The mixing ratio of the total mass of the microporous polymer and the dopamine hydrochloride to the total volume of the tris buffer solution and the ultrapure water is 14g/40 mL. The reaction temperature is room temperature, and the reaction time is 24 hours.

Preferably, in step S3, the adhesive solution is a silicone adhesive/o-xylene solution, and the mass concentration of the silicone adhesive in the silicone adhesive/o-xylene solution is 0.2 to 0.8 g/mL. The length of the surface coating is 1-2 cm, and the thickness is 5-50 μm.

More preferably, the mass concentration of the silicone adhesive in the silicone adhesive/o-xylene solution is 0.5 g/mL. The prepared solid-phase microextraction probe is inserted into the SPME casing pipe, and can be used after being aged for 10-20 min at 250 ℃ in nitrogen protection before being used each time.

The microporous polymer is a porous hypercrosslinked polymer, has strong hydrophobicity and a porous property of bimodal micropore distribution, and the pore diameter distribution of two positions are respectively arranged

And

and has high adsorption affinity for hydrophobic compounds. The microporous polymer is modified by selectively modifying the porous polydopamine to obtain a microporous polymer/polydopamine composite material, the composite polymer can be soaked by water, and is distributed in single micropores, and the pore diameters are distributed inAnd the method has high-efficiency broad-spectrum extraction performance on hydrophobic and hydrophilic compounds.

The selective in-hole polydopamine modification strategy of the microporous polymer is based on the following principle: the diameter of the dopamine molecule is aboutWhen the dopamine molecules are adsorbed in the small pores of the microporous polymer, the pores cannot completely wrap the dopamine molecules, and amino groups or carboxyl groups at two ends of the molecules are exposed outside the pores to contact with free dopamine molecules in a system and undergo auto-polymerizationShould be used. When dopamine molecules are adsorbed in larger pores in the microporous polymer, the pores can completely wrap the dopamine molecules to make the dopamine molecules difficult to contact free dopamine molecules in a system, and the dopamine molecules cannot undergo a self-polymerization reaction, so that the dopamine molecules in the large pores are washed out after the reaction is finished, and the size of the microporous polymer is in the range of the size of the microporous polymerThe larger pores in between are preserved. The selective modification strategy of the porous polydopamine leads the modified microporous polymer/polydopamine composite material to have the hydrophilic functional group of the polydopamine and the hydrophobic pores of the original microporous polymer, so that the composite polymer has better adsorption affinity and broad-spectrum extraction performance on both hydrophilic and hydrophobic polymers.

The core of the solid phase microextraction technology lies in the solid phase microextraction coating on the extraction probe, the invention uses microporous polymer/polydopamine composite material as adsorbent of the surface coating of the solid phase microextraction probe, the material has the characteristics of rich surface functional groups, high-efficiency broad-spectrum extraction performance on hydrophobic and hydrophilic compounds, and wide collection of non-target volatile pollutants, and can be used as coating material for preparing the solid phase microextraction probe with broad-spectrum pollutant collection effect. The solid phase micro-extraction probe prepared by using the microporous polymer/polydopamine composite material as the surface coating adsorbent has the advantages of good broad-spectrum extraction performance, high enrichment performance, high stability and capability of being recycled for more than 100 times, and can be applied to enrichment detection of volatile pollutants.

Compared with the prior art, the invention has the following beneficial effects:

the selective porous polydopamine modification strategy of the microporous polymer is simple and convenient to operate, the reaction condition is mild, and the microporous polymer/polydopamine composite material obtained after modification is rich in surface functional groups and has enhanced hydrophobic-hydrophilic balance performance and broad-spectrum efficient adsorption performance on hydrophobic and hydrophilic substances. The solid phase micro-extraction probe of the microporous polymer/polydopamine composite material provided by the invention has the advantages of good broad-spectrum extraction performance, high enrichment performance, high stability and capability of being recycled for more than 100 times, and can effectively enrich various volatile pollutants.

Drawings

Figure 1 is a graph of the water contact angle and pore size distribution of the microporous polymer and microporous polymer/polydopamine composite provided in example 1.

FIG. 2 is a microscopic morphology (scale bar 500.0 μm) of the microporous polymer/polydopamine composite solid-phase microextraction probe prepared in example 1, characterized by a scanning electron microscope.

FIG. 3 is a microscopic morphology (10.0 μm scale bar) of the microporous polymer/polydopamine composite solid-phase microextraction probe prepared in example 1, characterized by a scanning electron microscope.

FIG. 4 shows the enrichment efficiency ratio EF of the microporous polymer probe and the microporous polymer/polydopamine composite probe provided in test example 1 for three types of analytes_{[email protected]}/EF_KAPlogK with analyte_owA variation diagram of (2). KAP-microporous polymer, KAP @ PDA-microporous polymer/polydopamine composite.

FIG. 5 is a graph comparing the extraction performance of the microporous polymer/polydopamine composite probe (KAP @ PDA) provided in application example 1 with commercial probes (PDMS, DVB/CAR/PDMS) for 36 volatile contaminants.

Detailed Description

The present invention will be further described with reference to the following specific examples and drawings, which are not intended to limit the invention in any manner. Reagents, methods and apparatus used in the present invention are conventional in the art unless otherwise indicated.

Unless otherwise indicated, reagents and materials used in the present invention are commercially available.