WO2019233582A1

WO2019233582A1 - Porous materials based solid phase extraction of analyte from beverages

Info

Publication number: WO2019233582A1
Application number: PCT/EP2018/065019
Authority: WO
Inventors: Tjalf Pirk; Suresh PALALE; Andreas Gehrold; Kaushal SAGAR
Original assignee: Robert Bosch Gmbh
Priority date: 2018-06-07
Filing date: 2018-06-07
Publication date: 2019-12-12

Abstract

The application relates to a method of forming a porous material for use in solid phase extraction of one or more targets in a liquid analyte comprising the consecutive removal of first and second porogens from a solid matrix.

Description

POROUS MATERIALS BASED SOLID PHASE EXTRACTION OF ANALYTE FROM

BEVERAGES

FIELD OF THE TECHNOLOGY

[0001] The present disclosure relates to a method of forming a porous material for use in solid phase extraction of one or more targets in a liquid analyte. The present disclosure also relates to such a porous material and its use in solid phase extraction of one or more targets in a liquid analyte.

BACKGROUND ART

[0002] Various methods have been reported for selective removal or sensing (e.g. detecting, identifying and/or characterizing) of unwanted chemical and/or biological compounds from beverages and other analytes, which are often substances that adversely affect consumers’ products, such as having an effect on the taste and/or harms the health of consumers. Such methods conventionally include molecular imprinting, use of a nanofiber mesh etc.

[0003] In molecular imprinting, a substrate or scaffold may be tailored with recognition sites for a target. Such recognition sites may be sites that are functionalized or imprinted with a molecule or entity that specifically binds to a target. This meant that only specific targets are removed based on the molecule or entity that is used. The binding of the specific target to the molecule or entity may arise from covalent bond, non-covalent bond, hydrogen bond and/or electrostatic attractions.

[0004] As for nanofiber mesh, such mesh may rely on the attractive forces/bonds as mentioned above to isolate specific unwanted compounds. This meant that the mesh selectively filters unwanted compounds, and in order to remove other compounds, another mesh having a different specificity needs to be used.

[0005] Despite availability of such conventional methods, they neither address nor effectively address poor sensitivity arising from relatively small surface to volume ratio, which makes selective binding of targets in an analyte, particularly when the targets are in trace level (i.e. minute amounts), challenging. Conventional methods also tend not to be versatile as they identify and/or remove specific or only one kind of target, and not various common targets which may be found in an analyte. For example, pesticides may be commonly found in a variety of wines and conventional methods may specifically remove a component of the pesticide or one kind of pesticide.

[0006] Accordingly, there is a need to provide for a solution that ameliorates the disadvantages as mentioned above.

SUMMARY

[0007] In one aspect, there is provided for a method of forming a porous material for use in solid phase extraction of one or more targets (15) in a liquid analyte, comprising: providing a solid matrix (7) comprising a first plurality of porogens (9) and a second plurality of porogens (1 ), wherein each porogen from the first plurality of porogens (9) is comprised of a size larger than each of the porogen from the second plurality of porogens (1 );

removing the first plurality of porogens (9) to define a first plurality of pores (1 1 ) within the solid matrix (7); and

removing the second plurality of porogens (1 ) after removing the first plurality of porogens (9) to define a second plurality of pores (13) within the solid matrix (7), wherein each pore from the first plurality of pores (1 1 ) is comprised of a size larger than each of the pore from the second plurality of pores (13), thereby forming the porous material.

[0008] In another aspect, there is provided for use of a porous material obtained by a method according to the present disclosure in solid phase extraction of one or more targets (15) in a liquid analyte, wherein the use comprises contacting the porous material with the liquid analyte for removing one or more targets (15) from the liquid analyte.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In the drawings, like reference characters generally refer to like parts throughout the different views. The drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention. In the following description, various embodiments of the present disclosure are described with reference to the following drawings, in which:

[0010] FIG. 1 shows a schematic process flow of forming the porous material according to various embodiments described herein.

DETAILED DESCRIPTION

[0011] The following detailed description refers to the accompanying drawings (i.e. FIG. 1 ) that show, by way of illustration, specific details and embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments may be utilized, and changes may be made without departing from the scope of the invention. The various embodiments are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments. Features that are described in the context of an embodiment may correspondingly be applicable to the same or similar features in the other embodiments. Features that are described in the context of an embodiment may correspondingly be applicable to the other embodiments, even if not explicitly described in these other embodiments. Furthermore, additions and/or combinations and/or alternatives as described for a feature in the context of an embodiment may correspondingly be applicable to the same or similar feature in the other embodiments.

[0012] In the context of the present disclosure, the phrase“liquid analyte” refers to a liquid or a mixture of liquids whose constituent(s) is to be detected, identified and/or removed. Non-limiting examples may include alcohol, fruit juice, any other dietary, therapeutic or prophylatic beverages. [0013] In the context of the present disclosure, the term“target” refers to a constituent of the liquid analyte, which is to be isolated from the liquid analyte. Non-limiting examples may include preservatives, pesticides and/or any other chemicals that have an adverse effect on the taste of a consumer product and/or health of a consumer.

[0014] The term “porogen”, as used herein, refers to a material that forms pores in another material.

[0015] The expression“biological fluid”, as used herein, refers to a liquid containing biological entities. A non-limiting example of biological fluid is a tissue fluid.

[0016] The phrase “biological entities”, as used herein, refers to any antibodies, bacteria, biological drugs, cells, enzymes, hormones, nucleic acids, proteins, receptors, tissues, viruses and substances that form such biological entities (e.g. amino acids).

[0017] The term“microscale” refers to a dimension ranging from 1 mhh to less than 100 mhh. For example, a microscale channel may have a width that falls in such a range. In another example, a microscale pore may have a size that falls in such a range.

[0018] The term“mesoscale” refers to a dimension ranging from 100 nm to less than 1 mhh. For example, a mesoscale channel may have a width that falls in such a range. In another example, a mesoscale pore may have a size that falls in such a range.

[0019] The term“nanoscale” refers to a dimension ranging from 1 nm to less than 100 nm. For example, a nanoscale channel may have a width that falls in such a range. In another example, a nanoscale pore may have a size that falls in such a range.

[0020] The word “substantially” does not exclude “completely” e.g. a composition which is “substantially free” from Y may be completely free from Y. Where necessary, the word “substantially” may be omitted from the definition of the invention.

[0021] In the context of various embodiments, the articles“a”,“an” and“the” as used with regard to a feature or element include a reference to one or more of the features or elements.

[0022] In the context of various embodiments, the term“about” or“approximately” as applied to a numeric value encompasses the exact value and a reasonable variance.

[0023] As used herein, the term“and/or” includes any and all combinations of one or more of the associated listed items.

[0024] As used herein, the phrase of the form of“at least one of A and B” may include A or B or both A and B. Correspondingly, the phrase of the form of “at least one of A and B and C”, or including further listed items, may include any and all combinations of one or more of the associated listed items.

[0025] The present disclosure relates to a method of forming a porous material for use in solid phase extraction of one or more targets (15) in a liquid analyte. The present disclosure also relates to such a porous material and its use in such solid phase extraction. The porous material, in the present disclosure, is composed of a solid scaffold or solid substrate.

[0026] The present method, present porous material and its use are advantageous in that there is enhanced sensitivity and versatility. [0027] Sensitivity is enhanced as the present method results in a porous material (e.g. a microporous or nanoporous material) that exhibits a significantly increased or large surface area of 10 m²/g to 300 m²/g. The increased surface area allows for more interactions between the target (15) and the increased number of recognition or entrapment sites in the porous material, and more interactions in turn enhance overall sensitivity for selective removal of targets (15), that are present in trace level, from the analytes. The increased surface area is attributed to a first plurality of porogens (9), which induce porosity in the solid matrix (7), as used in the present method. The increased surface area may also be attributed to a second plurality of porogens (1 ) as used in the present method. In addition, surface functionality of the porous material may be chosen to suit the analyte of choice, e.g. wine, juice, or any other beverage, for an even further improved interaction between recognition or entrapment sites of the porous material and target(s) (15). When the analyte flows through the microscale, mesoscale or nanoscale channels of the present porous material, which may be further functionalized, interaction between the analyte to be isolated and the pores is already largely enhanced, and with the further functionalization, binding efficiency and removal of unwanted compounds are even more enhanced.

[0028] Enhanced versatility is also provided by the present method, porous material and its uses. Analyte samples, such as wine, fruit juices, typically contain different pesticides and/or preservatives, which have an adverse effect on the product’s taste and/or health of consumers. Such common targets (15) can be removed using the present porous material, which represents a single solution for a wide variety of targets (15) while more than one solution is often needed for conventional approaches. Hence, the present method, porous material and its use provide enhanced versatility to remove a wide variety of targets (15).

[0029] According to the present disclosure, there is provided for a method of forming a porous material for use in solid phase extraction of one or more targets (15) in a liquid analyte, comprising providing a solid matrix (7) comprising a first plurality of porogens (9) and a second plurality of porogens (1 ), wherein each porogen from the first plurality of porogens (9) is comprised of a size larger than each of the porogen from the second plurality of porogens (1 ), removing the first plurality of porogens (9) to define a first plurality of pores (1 1 ) within the solid matrix (7), and removing the second plurality of porogens (1 ) after removing the first plurality of porogens (9) to define a second plurality of pores (13) within the solid matrix (7), wherein each pore from the first plurality of pores (1 1 ) is comprised of a size larger than each of the pore from the second plurality of pores (13), thereby forming the porous material.

[0030] In various embodiments of the present method, the materials for forming the first plurality of porogens (9), second plurality of porogens (1 ) and the solid matrix (7) may be mixed together as a first step (100) for forming the present porous material. The materials may be polymerized and may self assemble into a solid matrix (7) comprising the first plurality of porogens (9) and second plurality of porogens (1 ). Hence, the present method is advantageous in that it is a convenient process for fabricating the present porous material, as opposed to conventional processes that require additional steps for materials to be added at different stages. [0031] The material forming the solid matrix (7) may be called the majority component (3) or majority block (3) in the present disclosure because it serves as the continuous phase of the present porous material. That is to say, it forms the bulk of the present porous material. The material forming the first plurality of porogens (9) may be called the minority component (5) or minority block (5) in the present disclosure as they are used in a lesser amount compared to the majority component (3). The minority component (5) may also be called the sacrificial component (5) as it serves as a sacrificial phase of the present porous material. That is to say, it is removed from the resultant porous material to form the main group of larger pores. Advantageously, the first plurality of porogens (9) increase the surface area of the solid matrix (7). The increase in surface area allows for more of the one or more targets (15) to be present in the solid matrix (7). This in turn allows for increased entrapment of the one or more targets (15) in the solid matrix (7). The material for the second plurality of porogens (1 ) may be interchangeably referred to as “sacrificial template”,“template molecules” or“template entities” in the present disclosure because they form sites for entrapping targets (15). The template molecules are removed after removing the first plurality of porogens (9).

[0032] In various embodiments, the majority component (3) forming the solid matrix (7) may be, for example, precursors or monomers that form a copolymer (block or random), a polymer blend, a polymer composite, metal organic frameworks, a metal oxide or an inorganic material. This means that the solid matrix (7) may be composed of a copolymer (block or random), a polymer blend, a polymer composite, metal organic frameworks, a metal oxide or an inorganic material.

[0033] As formation of the solid matrix (7), first plurality of porogens (9) and second plurality of porogens (1 ) may occur at the same time or at different speed in various instances, providing the solid matrix (7), in some embodiments, may comprise polymerizing monomers in the presence of the first plurality of porogens (9) and the second plurality of porogens (1 ) to form the solid matrix (7). This occurs when the first plurality of porogens (9) and the second plurality of porogens (1 ) complete formation before the solid matrix (7).

[0034] In some embodiments, the majority component (3) may, for example, comprise or consist of monomers which may be polymerized to butyl rubber, nitrile rubber, polybutadiene, polyisoprene, polyacrylic acid, polypyrrole, polyurethane, polyvinylpolypyrrolidone, polysilicone and styrene-butadiene rubber. This means that the solid matrix (7) may, for example, comprise or consist of butyl rubber, nitrile rubber, polybutadiene, polyisoprene, polyacrylic acid, polypyrrole, polyvinylpolypyrrolidone, polysilicone and/or styrene-butadiene rubber, according to some embodiments. In some embodiments, the solid matrix (7) may comprise, without being limited to, butyl rubber, chloroprene, nitrile rubber, polybutadiene, polyisoprene, polyacrylic acid, polypyrrole, polyurethane, polyvinylpolypyrrolidone, polysilicone and/or styrene-butadiene rubber. Such nonlimiting examples of polymers are advantageous as they can be cross-linked. Cross-linking imparts structural rigidity to the polymer chains necessary to preserve porosity of the solid matrix (7). Thermodynamically, an increased surface area when forming a porous structure is entropically not favored. Therefore, to retain a porous structure, cross-linking may be carried out to maintain the porosity of the solid matrix (7) and thus the increased surface area. In such embodiments, the majority component (3) may be physically or chemically cross-linked. The cross-linking may be applied to the solid matrix (7) before, during and/or after it is formed. Physical cross-linking may be achieved by, for example, exposing the majority component (3) or solid matrix (7) to a magnetic field. Chemical cross-linking may be achieved by using any suitable chemical compounds that form a cross-linked network in the solid matrix (7). Chemical cross-linking may also be achieved by, for example, exposing the majority component (3) or solid matrix (7) to thermal radiation or ultraviolet radiation.

[0035] In some embodiments, thermoplastic polymers can be used as the majority component (3) for forming the solid matrix (7). Such thermoplastic polymers may, for example, comprise or consist of polystyrene, polymethyl acrylate, polyvinyl chloride, polyvinyl acetate, polyamide, polycarbonate, polysulfone. Such non-limiting examples of thermoplastic polymers can retain the induced porosity for increased surface area in the solid matrix (7) without the need for cross-linking due to their high glass transition temperatures (e.g. above room temperature of 25°C). In cases where thermoplastic polymers are used, the porous structure in solid matrix (7) is also retained after removal of the first plurality of porogens (9).

[0036] In various embodiments, the solid matrix (7) may be formed from the materials disclosed above, for example, the solid matrix (7) may comprise or consist of butyl rubber, chloroprene, nitrile rubber, polybutadiene, polyisoprene, polyacrylic acid, polypyrrole, polyurethane, polyvinylpolypyrrolidone, polysilicone, styrene-butadiene rubber, polystyrene, polymethyl acrylate, polyvinyl chloride, polyvinyl acetate, polyamide, polycarbonate, and/or polysulfone.

[0037] In other embodiments, the majority component (3) may, for example, comprise or consist of precursors which form graphene oxide coated particles, magnetic particles, metal oxide particles, metal organic frameworks, silica particles and/or thermoplastic polymer. This means that the solid matrix (7) may, for example, comprise or consist of graphene oxide coated particles, magnetic particles, metal oxide particles, metal organic frameworks, silica particles and/or thermoplastic polymer, according to the other embodiments. In embodiments involving such materials, cross-linking of the majority component (3) and the solid matrix (7) may not be necessary. In embodiments where such materials possess magnetic properties, the materials may be useful for forming magnetic elastomers. Magnetic elastomers are composites in which magnetic particles are loaded in an elastomeric matrix. The magnetic particles may be arranged in a particular manner resulting in an anisotropic phase within the elastomeric matrix. The anisotropic arrangement of magnetic particles serves to form a cross-linked network, which occurs during a curing process in the presence of an applied magnetic field.

[0038] Accordingly, for the earlier embodiments where cross-linkable materials (e.g. polymers) are used, providing a solid matrix (7) may comprise providing a cross-linking agent for forming a cross-linked network in the solid matrix (7). The cross-linking agent may be any suitable physical or chemical means as described above. Cross-linking allows swelling of the majority component (3) without altering structural rigidity of the resultant solid matrix (7), and this allows for better access of solvents and/or etching agents to the minority domains (i.e. where the minority components (5) are located) in the solid matrix (7), overcoming the mass transfer constraints imposed by, for example, the majority components (3) and the internal structure of the solid matrix (7). For example, diffusion of the solvents and/or etching agents across and/or into the majority components (3) or solid matrix (7) to reach the minority domains may be accelerated with cross- linking, thereby mitigating the mass transfer constraint as mentioned above. When the solvents and/or etching agents have better access to the minority domains, the first plurality of porogens (9) may be accessibly removed.

[0039] The solid matrix (7) of the resultant porous material may be called a solid phase scaffold (i.e. solid scaffold) as it serves as a scaffold for incorporating the materials forming the first plurality of porogens (9) and second plurality of porogens (1 ). The solid matrix (7) may be in the form of a film, membrane or particle.

[0040] In some embodiments of the present method, step (100) may involve polymerizing the minority component (5) to form the first plurality of porogens (9). The first plurality of porogens (9) may be, for example, selected from the group consisting of polyethylene glycol, polyacrylic acid, polysiloxane, polyvinyl alcohol, silica particles, wax, and combinations thereof.

[0041] As for the second plurality of porogens (1 ) (i.e. template entities), they may be, for example, selected from the substances that form the one or more targets (15). When the template entities used are the same as the one or more targets (15), the second plurality of pores (13) that are formed advantageously entrap the one or more targets (15) more effectively as the pores mimic the structure of such targets (15). This means that the second plurality of porogens (1 ) may, for example, comprise or consist of, azoxystrobin, carbendazim, carbaryl, chlorpyrifos, cyprodinil, fluazinam, parathion-methyl, pyrimethanil, tebuconazole, thiophanate-methyl, estrogen, progesterone, recombinant bovine growth hormone, testosterone, casein, gelatin, gluten, isinglass, bacteria and/or virus. A mixture of template entities may be used to allow the resultant porous material to entrap various kinds of targets (15) at the same time.

[0042] As mentioned above, in the present method, the materials may self assemble, during which the second plurality of porogens (1 ) may be disposed within the solid matrix (7) to define or form the second plurality of pores (13) at a polymer-air interface when the second plurality of porogens (1 ) are removed. This means that the second plurality of pores (13) may be formed along the boundaries defining or delineating the first plurality of pores (1 1 ) and the solid matrix (7), i.e. the interface between the solid matrix (7) and the first plurality of pores (1 1 ). The second plurality of porogens (1 ) may also be disposed at any position within the solid matrix (7) that becomes exposed to air after the first plurality of porogens (9) are removed. The second plurality of porogens (1 ) may also be disposed anywhere within the solid matrix (7). In other embodiments, the present method may comprise selectively (e.g. manually) disposing the second plurality of porogens (1 ) within the solid matrix (7) in one or more of the manners as described above. According to various embodiments, providing the solid matrix (7) may comprise disposing the second plurality of porogens (1 ) within the solid matrix (7) to define the second plurality of pores (1 1 ) at a polymer-air interface when the second plurality of porogens (1 ) are removed. This advantageously increases entrapment or capture of the one or more targets (15). As disclosed above, the first plurality of porogens (9) provide for more surface area and this allows for more of the one or more targets (15) to be present in the solid matrix (7). Disposing the second plurality of porogens (1 ) at the polymer-air interface in the first plurality of pores (1 1 ), which are formed from the first plurality of porogens (9), helps to increase the amount of targets (15) that are entrapped or captured. Hence, disposing the second plurality of porogens (1 ) at other locations where there are lower surface area, i.e. no targets or less targets (15) passing through or into the solid matrix (7), may not be as effective for extraction.

[0043] After formation of the solid matrix (7) with the first plurality of porogens (9) and second plurality of porogens (1 ) incoporated therein, the minority or sacrificial component (5), which forms into the first plurality of porogens (9) may be removed via step (200). Removal of the sacrificial component (5) (i.e. first plurality of porogens (9)) can be carried out by wet chemical processes, such as but not limited to, washing, etching, hydrolysis or chemical degradation, or by physical processes, such as but not limited to, heating or ultraviolet radiation. The first plurality of porogens (9) may be removed after cross-linking of the majority component (3) or solid matrix (7). After step (200), removal of the first plurality of porogens (9) creates or induces porosity (e.g. microscale, nanoscale or both) in the solid matrix (7), thereby resulting in a high surface area. Thereafter, the second plurality of porogens (1 ) (i.e. the template molecules) are removed in step (300). The same means for removing the first plurality of porogens (9) may be applied for step (300). The removal of template molecules can also be carried out by washing with organic and/or inorganic solvents, water and/or mixtures thereof. Non-limiting examples of such solvents include acetone, acetonitrile, chloroform, cyclohexane, dimethyl formamide, dimethyl sulfoxide, ethanol, methanol and/or tetrahydrofuran. Such solvents, may or may not contain a chemical etchant for chemical degradation or dissolution of the second plurality of porogens (1 ). Such chemical etchant may include, but not limited to, hydrogen fluoride, tetrabutylammonium fluoride, trifluoroacetic acid.

[0044] The removal of the second plurality of porogens (1 ) to form the second plurality of pores (13) may create an even higher surface area for the porous material. This is because the second plurality of pores (13) are advantageously disposed and situated at the polymer-air interface, e.g. at the boundaries where the first plurality of pores (1 1 ) are exposed to air. This means when the liquid analyte comprising the one or more targets (15) flows (400) through the first plurality of pores (1 1 ), the liquid analyte also comes into contact with the second plurality of pores (13). The second plurality of pores (13), being smaller in size than the first plurality of pores (1 1 ) and disposed at the boundary of the first plurality of pores (1 1 ), may create turbulence and cause the one or more targets (15) to become trap in the second plurality of pores (13). The second plurality of pores (13) hence serve as entrapment sites for the one or more targets (15). The liquid analyte may be subjected to pressure when flowing (400) through the first plurality of pores (1 1 ) and second plurality of pores (13). Such a pressure may help entrap the one or more targets (15) in the second plurality of pores (13). [0045] The liquid analyte may be any consumer product, such as but not limited, dietary, therapeutic, prophylatic beverages. This may include, for example, alcohol, biological fluid, fruit juice, milk or other nutritional formulations etc.

[0046] The one or more targets (15) may have an adverse effect on the taste of consumers’ products or may be a harmful substance to consumers when ingested over a short term or a prolonged period. The one or more targets (15) may be, for example, a pesticide(s) and/or preservatives. The one or more targets (15) may, for example, comprise or consist of azoxystrobin, carbendazim, carbaryl, chlorpyrifos, cyprodinil, fluazinam, parathion-methyl, pyrimethanil, tebuconazole, thiophanate-methyl, estrogen, progesterone, recombinant bovine growth hormone, testosterone, casein, gelatin, gluten, isinglass, bacteria and/or virus.

[0047] In the present disclosure, there is also provided for the use of a porous material, obtained by the method as described above, in solid phase extraction of one or more targets (15) in a liquid analyte, wherein the use may comprise contacting the porous material with the liquid analyte for removing the one or more targets (15) from the liquid analyte. The present porous material may also be used as a porous polymer scaffold that can be combined with molecular imprinting techniques for solid phase extraction of one or more targets (15) in a liquid analyte.

[0048] In one example, the present porous material may be used to isolate and remove harmful bacteria and/or viruses from the liquid analyte.

[0049] Various embodiments of the present method, and advantages associated with various embodiments of the present method, as described above may be applicable to the present porous material and use(s) of the present porous material, and vice versa.

[0050] The present porous material and use of the present porous material is at least advantageous in that an even higher surface area for entrapping one or more targets (15) from a liquid analyte is provided. Extraction of such targets (15) is carried out with the present porous material in its solid phase, without the need to convert the present porous material to the same liquid state as the liquid analyte.

[0051] In various embodiments, the porous material may, for example, comprise a surface area of 10 m²/g to 300 m²/g, 50 m²/g to 300 m²/g, 100 m²/g to 300 m²/g, 150 m²/g to 300 m²/g, 200 m²/g to 300 m²/g, or 250 m²/g to 300 m²/g. Such high surface areas ensure good accessibility for the one or more targets (15) to be trapped in the abundant entrapment sites of the solid matrix (7) of the present porous material. The incoming targets (15) can bind to these sites, even if the targets (15) are present at very low concentrations in the analyte. The binding of the targets (15) at the entrapment sites of the solid matrix (7) may arise from covalent, hydrogen, ionic or electrostatic interactions. To entrap or capture the one or more targets (15) in the second plurality of pores (13), chemical, physical and/or electrostatic interaction between the targets (15) and the entrapment sites, i.e. the second plurality of pores (13), may be relied upon.

[0052] In various embodiments, the entrapment and/or capture of the one or more targets (15) can be reversible or irreversible. This depends on the nature of binding between the one or more targets (15) and the entrapment or capture sites formed by the second plurality of pores (13). For example, when the binding is covalent or ionic in nature, it may be difficult to reverse the entrapment or capture of the one or more targets (15). However, if the binding arises from electrostatic attraction or physical trapping, the entrapment or capture may be reversed by techniques such as multiple washing steps with solvent(s), ion exchange, use of higher affinity binding agents like EDTA (ethylenediaminetetraacetic acid) etc. to remove the targets (15) from the second plurality of pores (13). Any other suitable techniques that help to release the entrapped or captured targets (15) from the second plurality of pores (13) may be used.

[0053] In various embodiments, the liquid analyte may, for example, comprise alcohol, biological fluid, fruit juice, a beverage, or mixtures thereof, with or without pesticides and/or preservatives.

[0054] In various embodiments, the one or more targets (15) may, for example, comprise azoxystrobin, carbendazim, carbaryl, chlorpyrifos, cyprodinil, fluazinam, parathion-methyl, pyrimethanil, tebuconazole, thiophanate-methyl, estrogen, progesterone, recombinant bovine growth hormone, testosterone, casein, gelatin, gluten, isinglass, bacteria and/or virus.

[0055] One skilled in the art would readily appreciate that the present invention is well adapted to carry out the objects and obtain the ends and advantages mentioned, as well as those inherent therein. Further, it will be readily apparent to one skilled in the art that varying substitutions and modifications may be made to the invention disclosed herein without departing from the scope and spirit of the invention. The methods, procedures, materials, and their uses described herein are presently representative of preferred embodiments, are exemplary, and are not intended as limitations on the scope of the invention. Changes therein and other uses will occur to those skilled in the art which are encompassed within the spirit of the invention are defined by the scope of the claims. The listing or discussion of a previously published document in this specification should not necessarily be taken as an acknowledgement that the document is part of the state of the art or is common general knowledge.

[0056] The invention illustratively described herein may suitably be practiced in the absence of any element or elements, limitation or limitations, not specifically disclosed herein. Thus, for example, the terms “comprising”, “including,” containing”, etc. shall be read expansively and without limitation. The word "comprise" or variations such as "comprises" or "comprising" will accordingly be understood to imply the inclusion of a stated integer or groups of integers but not the exclusion of any other integer or group of integers. Additionally, the terms and expressions employed herein have been used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed. Thus, it should be understood that although the present invention has been specifically disclosed by exemplary embodiments and optional features, modification and variation of the inventions embodied therein herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention. [0057] The content of all documents and patent documents cited herein, if any, is incorporated by reference in their entirety.

Claims

1. A method of forming a porous material for use in solid phase extraction of one or more targets (15) in a liquid analyte, comprising:

providing a solid matrix (7) comprising a first plurality of porogens (9) and a second plurality of porogens (1 ), wherein each porogen from the first plurality of porogens (9) is comprised of a size larger than each of the porogen from the second plurality of porogens (1 );

2. The method according to claim 1 , wherein providing the solid matrix (7) comprises disposing the second plurality of porogens (1 ) within the solid matrix (7) to define the second plurality of pores (13) at a polymer-air interface when the second plurality of porogens (1 ) are removed.

3. The method according to claim 1 , wherein providing the solid matrix (7) comprises polymerizing monomers in the presence of the first plurality of porogens (9) and the second plurality of porogens (1 ) to form the solid matrix (7).

4. The method according to claim 1 , wherein providing a solid matrix (7) comprises providing a cross-linking agent for forming a cross-linked network in the solid matrix (7).

5. The method according to claim 1 , wherein the solid matrix (7) comprises butyl rubber, chloroprene, nitrile rubber, polybutadiene, polyisoprene, polyacrylic acid, polypyrrole, polyurethane, polyvinylpolypyrrolidone, polysilicone, styrene-butadiene rubber, polystyrene, polymethyl acrylate, polyvinyl chloride, polyvinyl acetate, polyamide, polycarbonate, and/or polysulfone.

6. The method according to claim 1 , wherein the solid matrix (7) comprises graphene oxide coated particles, magnetic particles, metal oxide particles, metal organic frameworks, silica particles and/or thermoplastic polymer.

7. The method according to claim 1 , wherein the first plurality of porogens (9) are selected from the group consisting of polyethylene glycol, polyacrylic acid, polysiloxane, polyvinyl alcohol, silica particles, wax, and combinations thereof.

8. The method according to claim 1 , wherein the second plurality of porogens (1 ) comprise azoxystrobin, carbendazim, carbaryl, chlorpyrifos, cyprodinil, fluazinam, parathion-methyl, pyrimethanil, tebuconazole, thiophanate-methyl, estrogen, progesterone, recombinant bovine growth hormone, testosterone, casein, gelatin, gluten, isinglass, bacteria and/or virus.

9. Use of a porous material obtained by a method according to claim 1 in solid phase extraction of one or more targets (15) in a liquid analyte, wherein the use comprises contacting the porous material with the liquid analyte for removing the one or more targets (15) from the liquid analyte.

10. The use according to claim 9, wherein the porous material comprises a surface area of 10 m²/g to 300 m²/g.

1 1. The use according to claim 9, wherein the liquid analyte comprises alcohol, biological fluid, fruit juice, milk, a beverage, or mixtures thereof, with or without pesticides and/or preservatives.

12. The use according to claim 9, wherein the one or more targets (15) comprise azoxystrobin, carbendazim, carbaryl, chlorpyrifos, cyprodinil, fluazinam, parathion-methyl, pyrimethanil, tebuconazole, thiophanate-methyl, estrogen, progesterone, recombinant bovine growth hormone, testosterone, casein, gelatin, gluten, isinglass, bacteria and/or virus.