WO2008113365A2

WO2008113365A2 - Device and method for isolation, concentration and/or identification of compounds

Info

Publication number: WO2008113365A2
Application number: PCT/DK2008/050071
Authority: WO
Inventors: Philipp Mayer; Fredrik Reichenberg; Lars TORÄNG
Original assignee: Aarhus Universitet
Priority date: 2007-03-19
Filing date: 2008-03-19
Publication date: 2008-09-25
Also published as: WO2008113365A3

Abstract

The invention relates to device and a method for isolating, concentrating and/or identifying at least one analyte by retaining the at least one analyte by a material comprising at least one polymeric material. The device may be a vial which comprises a supporting means supporting a retaining material made of a polymeric material optionally further including a non-polymeric material. The retaining material allows for a selective reversible retention of analyte(s) during solvent evaporation and subsequent elution from the retaining material into a well known volume of solvent. The device and method is especially useful within laboratory work or experiments, e.g. where concentrations of analytes are to be determined. Especially the location and geometry of the retaining material is suitable to retain the analyte(s) during the evaporative removal of the solvent.

Description

Device and method for isolation, concentration and/or identification of compounds

All patent and non-patent references cited in the present application, are also hereby incorporated by reference in their entirety.

Field of invention

The present invention relates to a device and a method for isolating, concentrating and/or identifying at least one analyte by retaining the at least one analyte by a material comprising at least one polymeric material. The device comprises a supporting means supporting a retaining material made of a polymeric material, which allows for a selective reversible retention of analyte(s) by the retaining material during solvent evaporation and subsequent elution from the retaining material into a well known volume of solvent. The device and method is especially useful within laboratory work or experiments, e.g. where concentrations of analytes are to be determined. Especially the location and geometry of the retaining material is suitable to retain the analyte(s) during the evaporative removal of the solvent.

Background of invention

When a compound (an analyte) is obtained in a solvent e.g. following an extraction process it is often important to analyze the compound e.g. by determining its amount in the solvent without loosing a significant fraction of the compound. Important challenges include (1 ) the reduction of the solvent volume in order to increase the analyte concentration, (2) the accurate control of the final solvent volume, (3) minimizing losses of the analyte e.g. by evaporation and (4) changing from one solvent to another solvent.

WO 2005/032685 (R. H. Wohleb) describes a device for extracting an analyte from a sample matrix. It comprises of a sorption vial with a conically shaped interior surface, which is coated with a sorbent material. A method for extracting an analyte from a sample matrix includes retaining the sorption vial within a sample vessel with the sorbent coating exposed to the sample matrix contained in the sample vessel. After the analyte partitioned from the sample and into the sorbent material, the sorption vial may be removed from the sample vessel and sealed, or a small amount of elution solvent may be added to the sorption vial before sealing. The sorption vial containing the analyte may then be stored or transported to a lab for further analysis.

US 2005/0059162 (R. H. Wohleb) describes a device for extracting an analyte from a sample matrix comprises a sorption vial with a conically shaped interior surface, which is coated with a sorbent material.

US 2006/01 10295 (R. H. Wohleb) describes a device for extracting an analyte from a sample matrix which comprises a closed well plate, each well is coated with a sorbent material. Preferably, the conically-shaped sorption well of the plate has a surface and interior bottom coated with sorptive material.

US 2005/0059162 and US 2006/01 10295 (R.H. Wohleb) both describe devices (1 ) with an internal sorbent coating rather than the lowest part of the device being filled with a polymer, (2) with a large sample-to-sorbent contact area rather than restricting the contact area to the final evaporation zone and (3) with applications to analyte extractions and diffusive sampling rather than to evaporative enrichment. These geometry of R.H. Wohlebs devices make them less suited for the application area of the present invention.

For the evaporative enrichment of analytes, a known technique for concentrating an analyte uses a high-boiling point solvent as a keeper added to the extract to avoid evaporating to dryness. Evaporation to dryness normally causes unacceptable analyte losses. This procedure has a number of disadvantages:

1 . Care must be taken to avoid that evaporation is continued to the point of dryness which means labour intensive manual supervision in the laboratory.

2. After evaporation of the first solvent (e.g. n-hexane) the analytes are dissolved in an unknown volume of the keeper (e.g. iso-octane) or a mixture of both solvents.

3. The method does not allow solvent switching to solvents that are not suited as keeper.

4. The final volume of the extract is difficult to control accurately. Simple and efficient methods are needed in the field of concentrating analytes in extracts, solvent change, analyte purification and analyte analysis. The method and device presented herein overcome the disadvantages mentioned above.

Summary of invention

The present invention relates to a device and a method for isolating, concentrating and/or identifying at least one compound/analyte by retaining the at least one analyte by a material comprising at least one polymeric material.

Disclosed herein is a device which comprises

• a supporting means capable of containing a liquid, and

• a retaining material comprising a polymeric material,

• wherein the supporting means supports the retaining material and • wherein the retaining material is capable of retaining at least one compound, i. when liquid is removed by evaporation and/or ii. in absence of any volatile solvent and/or iii. when the polymeric material and/or the at least one compound is in a substantially dry condition.

Preferably the retaining material is located in the supporting means so that the last part of the liquid will evaporate from the surface of the retaining material when subjected to suitable conditions.

The supporting means may be of any suitable form such as a vial or test tube, of any suitable material e.g. glass or metall. The vial supports a retaining material comprising a polymeric material suitable for retaining at least one compound/analyte when the retaining material comprising a polymeric material and/or the at least one compound/analyte is in a substantially dry condition.

The polymeric material may be selected from the group of polysiloxanes, polyethylene, polypropylene, latex, polybutadiene, polyisobutylene, polyurethanes, polyacrylate, polycyanoacrylate, polyvinyl acetate, polyethylene glycol, polymers incorporation ion- exchange resins, polystyrene divinylbenzene or a combination thereof. The retaining material may comprise at least one other material than the polymeric material described above. This at least one other material may be a non-polymeric material. The non-polymeric material may be activated carbon, antibodies, Tenax,, Florisil, Alumina. To the polymer may also be added some kind of reagent for the analyte, this may be e.g. a chromogenic indicator such as Naphthanil Diazo Blue B for detection of aflatoxins or fluorescein mercuric acetate for the determination of disulfide groups, or it may be a derivatisation agent as describes elsewhere herein. To the polymer may also be added some kind of reagent for the removal of interferences, this may e.g. be copper particles for the removal of sulphide in sediment or soil extracts.

In a preferred embodiment the device comprises a vial with at rounded or pointed inner bottom, where a polymeric material is located exclusively in and filling the narrow volume immediately above the pointed or rounded inner bottom of the vial. The polymeric material may be substituted with another retaining material described elsewhere herein.

Also disclosed is a method for isolating and/or concentrating at least one compound/analyte, the method comprising • providing at least one compound/analyte

• optionally dissolving and/or suspending the at least one compound/analyte in a first solvent,

• providing a retaining material which is capable of retaining the at least one compound/analyte, • adding the at least one compound/analyte optionally dissolved and/or suspended in the first solvent to the retaining material,

• evaporating at least a part of the first solvent,

• obtaining the at least one compound/analyte retained within and/or on the retaining material.

The at least one compound/analyte retained within and/or on the polymeric material may be re-dissolved to obtain the compound/analyte in a second solvent and/or in a known volume of a solvent. Preferably substantially all of the first solvent is evaporated. More preferably all of the first solvent is evaporated.

In a preferred embodiment the retaining material will be substantially dry following evaporation of the first solvent i.e. only the internal volume defined by the retaining material may comprise non-evaporated solvent.

In another preferred embodiment the retaining material will be entirely dry following evaporation of the first solvent i.e. no non-evaporated solvent is present in connection to the retaining material.

The device and the method of the present invention has the following advantages relative to prior art techniques for the evaporative enrichment of analytes in volatile solvent extracts:

1 . Higher recovery of (semi)volatile analytes.

2. Lower detection limits can be achieved with a given sample mass.

3. Less sample mass is required to achieve a certain detection limit.

4. Possibility to switch solvent without loss of analyte or detection limit. 5. Improved control of final extract volume.

6. Lessened risk for irreversible analyte binding of analyte to the surface of the evaporation glassware (adsorption).

7. Lessened tendency for chemical degradation of analyte (e.g. hydrolysis, oxidation and condensation reactions).

Description of Drawings

Fig. 1 illustrates the method of using the device described herein for concentrating a compound or an analyte. The sample extract (comprising the volatile first solvent and the analyte(s)) is placed in the device (panel a) and the first solvent is evaporated e.g. under a gentle stream of nitrogen gas. After evaporation e.g. to dryness the analyte(s) are deposited in and/or absorbed to the retaining material or the polymer (panel b) and can be recovered in a new volume of the first solvent and/or of a second solvent (panel c). The Figure also illustrates an example of a device preferable according to the present invention; A vial including a polymeric material where the polymeric material preferably is located in the bottom of a tapered tip.

Fig. 2. Results of recovery of several polychlorinated biphenyls (CB-x), hexachlorobenzene (HCB) and different organochlorine pesticides in vials produced according to the present invention as compared to traditional vials. Further description is given in Example 2.

Fig. 3. The figure illustrates different preferred embodiments of the device as keeper vials. The retaining material is located in the bottom volume of vials/tubes of different designs. The figure indicates the shape of the inner surface of the vials/tubes used as supporting means of the device of the present invention, thus the form of the outer surface may be different. The retaining material is consolidated and focused exactly at, and below, the area in the vials/tubes from where the last of the volatile solvent will evaporate during the method described in this invention.

Detailed description of the invention

The present invention relates to a device and a method for isolating, and/or concentrating and/or identifying at least one analyte initially dissolved or suspended in a liquid solvent by retaining the at least one analyte by a material comprising at least one polymeric material while/after removing the liquid solvent.

The device comprises a supporting means supporting a retaining material comprising a polymeric material and possible non-polymeric material, which allows for a selective reversible retention of analyte(s) by the retaining material during solvent evaporation and subsequent elution of analyte(s) from the polymeric retaining material into a well known volume of solvent added to the supporting means.

Especially the device with the retaining material is suitable to retain the analyte(s) under conditions where all volatile solvents are evaporated.

The device

In an aspect the invention relates to a device comprising • a supporting means capable of containing at least one volatile solvent containing at least one compound, and

• a retaining material comprising a polymeric material and optionally further a non- polymeric material, • wherein the supporting means supports the retaining material and

• wherein the retaining material is capable of retaining at least one compound in the absence of any volatile solvent and/or when removing the liquid by evaporation.

The retaining material comprising a polymeric material and possibly a non-polymeric material is located on and/or within the supporting means such that the retaining material can retain at least one compound initially contained in a volatile solvent contained in the supporting means after at least a part of the volatile solvent has been removed. Preferably all the volatile solvent is removed from the supporting means by evaporation.

In an embodiment the device comprises

• a supporting means capable of containing at least one volatile solvent containing at least one compound, and

• a retaining material comprising a polymeric material and possibly a non-polymeric material, said retaining material being located in the lower part of the supporting means,

• wherein said retaining material furthermore is located in the lower part of the supporting means from where the last part of a volatile solvent would evaporate.

• said retaining material has a shape determined by the evaporation of a volatile solvent into which said retaining material was dissolved or dispersed during the preparation of the device, and

• wherein the retaining material is capable of retaining at least one compound, when said retaining material and/or said at least one compound is present in the absence of any volatile solvent

The term "compound" is used to describe one or more compounds of interest, such that the compound(s) can be concentrated, purified and/or analysed as described herein. Generally "compound(s)" is the substance(s) that are to be retained within a retaining material. Also the term "analyte(s)" is used to describe the compound(s) to be retained by the retaining material. The supporting means is in at least one position capable of containing a liquid, such as a volatile solvent containing a compound, until the liquid evaporates and is removed as gaseous vapour under suitable conditions. This may involve heating or cooling, positive (carrier gas) or negative (vacuum) pressure and/or centrifugation or other conditions which influence the evaporation. The liquid is not intended to flow along or through the retaining material, but is by the supporting means kept in constant contact with the facing surface of the retaining material until evaporation is complete. As described elsewhere some liquid may still be present within the retaining material as the evaporation process is terminated.

The substantial or total absence of any volatile solvent together with compounds retained by the retaining material may be obtained during the use of the device. The retaining material may or may not contain volatile solvent before use, and may shortly before use and/or during use be dried to obtain the substantial or total absence of any volatile solvent at least for a period of time. By substantially absence of any volatile solvent is meant that all volatile solvent present around the polymeric material is removed e.g. by evaporation of the volatile solvent such that no volatile solvent is visible to the human eye, hereby a non-visible film of solvent may be present at the surface of the retaining material. By total absence of any volatile solvent is meant that all volatile solvent present in the supporting means, around and within the retaining material is removed e.g. by evaporation of the volatile solvent such that no further amounts of solvent can be evaporated from the device. The term "absence of any volatile solvent" or "absence of solvent" or "substantially dry condition" or similar formulation is used to describe both "substantial and total absence of any volatile solvent".

The absence of any volatile solvent may be indicated by one or more of the features: time elapse, visual inspection by the human eye, constant weight of the device, absence of vapor emerging from the device, and temperature increase of the device.

The device may include a retaining material comprising at least a polymeric material, which is capable of retaining at least one compound in the absence of volatile liquid solvent, including water. All volatile solvent, initially containing the compound(s) to be retained in the retaining material, is removed by evaporation from the polymeric material and/or the device and the compound(s) originally in the solution is retained by the polymeric material.

In an embodiment the supporting means can be made of any suitable material, such material can be selected from the group of polymers, plastics, glasses, ceramics, porcelains, metals or a combination thereof.

The supporting means can be made of a material with insignificant retention and/or permeability of the at least one compound which may be retained by the retaining material. The supporting means can also be of a material which allows no retention of the compound to be retained within the retaining material. By insignificant retention is meant that after application of the compound to the surface of the material of the supporting means the compound can be dissolved into a solvent appropriate for the compound. By insignificant permeability is meant that the compound can not diffuse into or though the material to such an extent that this hampers the isolation, concentration and/or identification of the compound. The supporting means can also be of a material which is compatible with (i.e. inert and stable in contact with) the retaining material and with the at least one compound.

In a preferred embodiment it is important that the material of the supporting means is diffusion tight for both the first and second solvent and the compound/analyte, also the material of the supporting means is non-sorptive, non-reactive towards; and does not release impurities to; or react with or dissolve into the first and/or second volatile solvent(s).

In another embodiment the material of the supporting means is not polymeric.

The supporting means can also be of a material which is inert in respect of chemically reactivity towards the at least one compound, a volatile solvent, the retaining material and/or a combination thereof.

In an embodiment the supporting means may be made of a material which can withstand a volatile solvent used for dissolving or re-dissolving at least one compound before and/or after the at least one compound is retained by the retaining material supported by the supporting means. As examples of materials suitable for supporting means can be mentioned neutral borosilicate glass, polytetrafluoroethylene (Teflon™) and stainless steel, nickel, copper and porcelain as they are compatible with all common volatile solvents.

Also other materials may be used for the supporting means, although some of these materials may be restricted to be used for retaining specific compounds within a polymeric material supported by the supporting means. Some salts of fluoride may corrode glass, metal, and ceramic supporting means; Teflon™ is in this case a recommendable alternative material.

In another embodiment the supporting means may be jacketed, insulated, shelled, silvered, coated, stained graduated, enqraved or of otherwise similar design.

In an embodiment the supporting means is made of at least two layers of material. The inner layer which is to be in contact with the polymeric material and/or the volatile solvent is made of a material as described elsewhere herein as a material for the supporting means and the outer layer(s) partly or entirely surrounding the inner layer may be of any suitable material. For example as supporting means for the device described herein may be selected ESR-Vacuum Tubes having an outer layer of biaxially-oriented polyethylene terephthalate polyester as a safety-coating to help prevent deforming and stress cracking and contain glass and content in the event of breakage, reducing the risk of injury from shards and potential exposure to hazardous materials.

In another embodiment the supporting means has a form and design selected from or similar to the group of receiver, cylinder, glass, ampoule, canister, pot, basin, jar, pitcher, cup, bottle, vial, test tube, flask, crucible, tube, beaker, multiwell plate, micro well plate or a plate with nanoliter small holes. When the term "vial" is used to describe the device this may refer to any design or form of the device, and especially to the forms mentioned above. For example in an embodiment the supporting means may be the collection trap of a freeze drying apparatus.

The vial may be shaped with straight, sloped, tapered, bulged, (vigreaux) indented, banded, or flat sides. The vial can have at least one mouth being either neckless or the neck is smooth, tapered, flared, flanged, lipped, grooved, lined, socketed, barbed, ball-joint, threaded, hooked, sintered, valved, ground and/or seated with grommet or O-ring. The neck may be straight vertical, side mounted or angled. The mouth may be capped or uncapped and/or conical, round bottomed, tapered or flat bottomed. A cap, stopper, cork, stopcock, septum, head, filter, or lid can be mounted, screwed on, twisted or pushed on/in, clamped, crimped, wired, or snapped over to the mouth of the vial to secure, close or seal the vial, or a cap head, funnel, disc, watch-glass or lid can be loosely fitted over the mouth. The cap and vial can be of a similar material or of different materials, e.g. a vial made of glass such as neutral borosilicate glass can be sealed with a cap made of polymer, e.g. polytetrafluoroethylene (Teflon™). Alternatively the mouth may be annealed.

The mouth of the vial may also house a distillation column, cold-finger, still-head, vacuum take-off, gas-delivery line, needle, pipette, SPME-fiber, thermometer, capillary, electrode, laser, irradiation source, camera, optic fiber, bio-sensor, indicator strip, or other means of detection of the analytes of interest as described elsewhere herein.

In an embodiment the vial has at least one pointed inner bottom and/or at least one flat bottom and/or at least one rounded bottom. The inner form of the vial may or may not be similar to the outer form of the vial. A vial with a pointed inner bottom may have a pointed outer bottom or a flat outer bottom. A pointed or rounded inner bottom can be preferred to be used in a vial firstly to locate the retaining material within the outermost volume immediately above this pointed or rounded inner bottom and secondly to secure that when a solvent evaporates from the vial, the last part of the solvent evaporates from the top surface area of the retaining material. When the compound(s) is/are retained in a small volume of retaining material e.g. shaped as a downward pointing cone with apex located at the pointed inner bottom, this shape facilitates the elution (re-dissolving) of the compound(s) to a small volume of solvent as the supporting mean and the force of gravity collects it over and in contact with the entire facing surface area of the conic body of the retaining material. In comparison, a greater volume of solvent would be needed to cover and contact the surface of a thin layer of retaining material spread over the interior side wall of the vial. In an embodiment a tapered vial having a pointed inner bottom internal volume may have the internal side wall slanting from the top and down to the pointed bottom, where the angle of the narrowing may be from 5 to 85 degrees. More preferred is when the pointed inner bottom has an angle between 10 and 75 degree, e.g. between 15 and 70 degree, such as between 20 and 60 degree, e.g. between 25 and 50 degree, such as between 30 and 40 degree. Preferred is an angle of the pointed inner bottom of about 35 degrees.

In an embodiment the supporting means or vial has an inner volume of less than 1 ,000 L, such as less than 750 L, e.g. less than 500 L, such as less then 250 L, e.g. less than 100 L, e.g. less than 50 L, such as less than 10 L, e.g. less than 5 L. Preferred is a volume of less than 2 L e.g. less than 1 L. More preferred is a volume less than 600 ml, e.g. between 10 μl_ and 550 ml. Also preferred is an inner volume in the range of 1 ml to 500 ml. Further preferred is a volume of between 1 ml to 250 ml. Also preferred is a volume of less than 200 ml, such as less than 150 ml, e.g. less than 100 ml, such as less than 50 ml, e.g. less than 25 ml, e.g. less than 15 ml, such as less than 10 ml, e.g. less than 5 ml, e.g. less than 4 ml, such as less than 3 ml, e.g. less than 2 ml, such as less than 1 ml, e.g. less than 0.5 ml.

If the liquid solvent volume is very large, it can first be reduced to e.g. 500 ml by other means and then transferred to a device according to the present invention before remaining volatile solvent is reduced. A large volume e.g. a volume of more than 500 ml may be reduced by dividing the volume into smaller volumes before the smaller volumes are transferred to devices according to the present invention. A large volume may also be reduced by evaporation of a part of the volatile solvent.

In another embodiment the polymeric material of the retaining material to retain at least one compound can be selected from the group of polysiloxanes, polyethylene, polypropylene, latex, polybutadiene, polyisobutylene, polyesters, polyurethanes, polyacrylate, polycyanoacrylate, polyvinyl acetate, polyethylene glycol, polymers incorporation ion-exchange resins, polystyrene divinylbenzene or a combination thereof. The retaining material may comprise one or more polymeric material mentioned herein and may also comprise a non-polymeric material such as those mentioned herein. Preferred embodiments or the retaining material comprises at least one polymeric material selected from the group of polysiloxanes, polyethylene, polypropylene, latex, polycyanoacrylate, polyvinyl acetate, polyethylene glycol, polymers incorporation ion- exchange resins, polystyrene divinylbenzene or a combination thereof.

Also preferred is polymeric material selected from the group of polybutadiene, polyisobutylene, polyurethanes, polyacrylate or a combination thereof.

Further preferred is polymeric material selected from the group of polycyanoacrylate, polyvinyl acetate, polyethylene glycol, quaternary ammonium anion-exchange resins, sulfonic or carboxylic cation-exchange resins, polystyrene divinylbenzene or a combination thereof. As examples of polymeric materials preferable when the compounds of interest are phenols, antibiotics, chlorinated pesticides or various aromatic and nitrogenous compounds including both narcotics and environmental organic contaminants are adsorbent styrene-divinylbenzene copolymers comprising 5- 20% divinylbenzene (e.g. the commercially available Amberlite® and Amberlyst® products, typically supplied in the form of small particles.)

Most preferred is the polymeric material polydimethylsiloxane.

Non-polymeric material of the retaining material may be activated carbon particles or surface-functionalized silica, for example octadecylated (LC-18) or aminopropylated (LC-NH₂) silica. They may also be copper particles for the removal of sulphides or palladium particles for the catalytic reaction of analytes or interferences.

One or more non-polymeric material may generally be supplied within the range of a few percent, e.g. 0.01 -10% of the amount of polymeric material.

The polymeric and/or non-polymeric material may be non-fibrous or fibres or a combination hereof. The fibre may have any suitable length, and may be a combination of short and longer fibre. There is no practical upper limit to the polymer molar (or molecular) mass of the fibre.

Examples of polymer blends may be but are not limited to: (1 ) low-density polyethylene with polydimethylsiloxane and ethylene vinyl acetate, (2) poly(methyl methacrylate) with poly(vinylidene fluoride), (3) polystyrene with polybutadiene and p-(hexafluoro-2- hydroxyisopropyl)styrene.

The polyethylene may be low density polyethylene and/or high density polyethylene where low density polyethylene is defined by a density range of 0.910 - 0.940 kg/I. High density polyethylene is defined by a density ≥0.941 kg/I. By latex is meant refined natural rubber or poly-isoprene. Polybutadiene may also include some derivates thereof e.g. styrene-butadiene. Polyisobutylene can also be denoted butyl rubber. An example of polyethylene glycol is carbowax™.

The retaining material can be a non-volatile polymer or a non-volatile combination of polymers.

In an embodiment the polymeric material is insoluble in at least one solvent useful for dissolving or redissolving the at least one compound/analyte. As an example crosslinked polydimethylsiloxane does not dissolve in any common volatile solvents (e.g. hexane, acetone and toluene).

In a further embodiment the retaining material is able to retain the at least one compound during an evaporation step. The evaporation can be performed as described elsewhere herein, and the conditions for retaining the compounds are also described elsewhere herein.

In an embodiment the retaining material may be physically located at a part of the vial or supporting means and in a position from where, when evaporating a solvent the last part of this solvent will evaporate from the supporting means. Hereby the retaining material is in good contact with the last remaining liquid solvent during the final phase of the evaporation process. In a vial with pointed inner bottom this means that the retaining material will be located in and fill the bottom volume in the vial with the smallest inner diameter of the bottom i.e. during the preparation of the device the retaining material is obtained as a body located in the most retracted volume above the tip and bottom of the vial. In a preferred embodiment the retaining material is only located in the bottom of the supporting means and has a configuration as described elsewhere herein and the retaining material is not provided as a coating of the walls of the vials or the vertical sides of the tip of the vials i.e. the part of the vials not constituting the bottom of the vial. A coating constitutes a thin layer covering a surface, which follows the curvature and geometry of the surface being coated. In the device described herein the bottom or bottom volume is filled with retaining material, where the geometry of this volume does not strictly follow the curvature and geometry of the supporting material bottom inner surfaces when the vial has a pointed inner bottom. The volume of the retaining material of the device described herein will generally not be of uniform thickness as is commonly understood by a coating.

In another preferred embodiment the retaining material is located in the bottom of a vial such that the design of the retaining material is determined by the gravity forces subjected to the retaining material during the process of producing the vial when a suspension/solution of the retaining material is located in the vial and the liquid part of this suspension/solution is evaporated. Thus the retaining material is focused in the bottom volume of the supporting means. Hereby the retaining material is not provided as a coating of the vial.

In an embodiment the retaining material of the device has a maximum thickness at the lowest point of the supporting means i.e. thickness of the retaining material increases towards the center of the tube in a tube with a pointed inner wall. This thickness may be at least 0.2 cm, such as at least 0.3 cm, e.g. at least 0.4 cm, such as at least 0.5 cm, e.g. at least 0.6 cm, such as at least 0.7 cm, e.g. at least 0.8 cm, such as at least 0.9 cm, e.g. at least 1 .0 cm, such as at least 1.2 cm, e.g. at least 1.4 cm, such as at least 1 .5 cm, e.g. at least 1.6 cm, such as at least 1 .8 cm, e.g. at least 2.0 cm, such as at least 2.5 cm, e.g. at least 3.0 cm, such as at least 3.5 cm, e.g. at least 4.0 cm.

In the device and method described herein it is not important to have a large surface area of the retaining material as the analyte of the liquid can be transferred from the liquid sample to the retaining material as the liquid just outside of the retaining material evaporates i.e. as the last part of the first solvent evaporates. When retaining an analyte as described herein during the final phase of an evaporation process, the device comprising a retaining material located in the bottom of the supporting means is superior to vials having a coating of the bottom and the lower part of the walls of the vial. The advantages of the device described herein are e.g. 1. The polymer is exactly placed where it is needed for receiving the analytes when the last fraction of the solvent evaporates. 2. The upper polymer surface is limited to that area where the analytes will enter the retaining material, and this will minimize evaporative losses of the analytes. With the device described herein the retaining material has a smaller (gas) surface-to-(retaining material)volume ratio than a device with a polymer coating of the lower part of a vial bottom.

The height of the retaining material at the center of the device may be several millimetres possibly exceeding 1 cm, which is much thicker than what is used in diffusive sampling were coating thicknesses typically are 0.5 -100 μm thick. Examples of thickness of the retaining material at the center of the divice may be about 2 cm, e.g. about 1.5 cm, such as about 1 cm, e.g. about 9 mm, such as about 8 mm, e.g. about 7 mm, such as about 6 mm, e.g. about 5 mm, such as about 4 mm, e.g. about 3 mm, such as about 2 mm, e.g. about 1 mm, such as about 0.5 mm, e.g. about 0.4 mm, such as about 0.3 mm, e.g. about 0.2 mm, such as about 0.1 mm.

The thickness of the retaining material at the center of the divice may also be at least 0.5 μm, such as at least 1 μm, e.g. at least 5 μm, such as at least 10 μm, e.g. at least 50 μm, such as at least 100 μm, e.g. at least 500 μm, such as at least 1 mm, e.g. at least 2 mm, such as at least 2 mm, e.g. at least 3 mm, such as at least 4 mm, e.g. at least 5 mm, such as at least 6 mm, e.g. at least 7 mm, such as at least 8 mm, e.g. at least 9 mm, such as at least 1 cm, e.g. at least 1.5 cm.

The retaining material comprising polymeric material can be supported by the supporting means due to adhesion of the polymeric material to the supporting means. The adhesion may be caused by (1 ) mechanical interlock/sewing/friction e.g. attachment due to filling of micropores on the surface of the supporting means prior to a cross-linking /polymerisation (2) The formation of chemical bonds (ionic, covalent or hydrogen bonds) across the joining surfaces. (3) Dispersive/induction adhesion (i.e. adsorption). The retaining material comprising polymeric material may also cover the entire bottom surface of the container or it may be present as a concentrated volume e.g. as a substantially spherical volume on the supporting means. Depending on the compound to be retained on and/or retained within the polymeric material, the polymeric material may be located on the supporting means by covering the last section of a pointed inner bottom or as a concentrated volume e.g. as a substantially spherical volume in the last section of a pointed inner bottom on the supporting means. The thickness of the polymer cover or spherical volume as well as the total volume of the polymeric material is described elsewhere herein.

The polymeric material may also be located as a polymeric phase at the bottom of a vial, hereby at least a part of the shape of the polymeric phase is determined by the form of the supporting means. Hereby the polymeric phase in e.g. a pointed inner bottom will have the three-dimensional form of substantially an inverted cone.

In an embodiment the polymeric material is located at the bottom of the vial in such a way that it has maximum contact with the last volume of solvent during the evaporation step in order to provide optimal mass transfer conditions for the analytes to the enter the polymer. The polymer location and geometry should at the same time have a minimized polymer to air interface in order to minimize evaporative analyte losses at the end of the evaporation process. The volume of the polymer shall be sufficient to retain the analyte and it should not exceed a level at which it becomes difficult to elute the analytes into the second solvent. The optimal design will depend on the target analytes with a relatively large polymer volume needed for highly volatile analytes and a smaller polymer volume for less volatile analytes.

The polymeric material may occupy a volume corresponding to less than 50% of the volume of the supporting means, such as less than 40%, e.g. less than 30%, such as less than 20 %. Preferred is when the polymeric material occupies between 0.001 to 10% of the internal volume of the supporting means. Also preferred is a volume of the polymeric material of less than 10%, such as less than 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1 %, 0.5%, 0.25%, 0.1 %, 0.05% in respect to the inner volume of the vial.

In an embodiment a small phase (e.g. volume of 3 μl) of a polymeric material (e.g. PDMS) fills up the lower tip of a conical vial (e.g. volume of 1.1 ml). The polymeric phase may be larger. It is to be understood that the size of the vial may be different, the volume of the polymeric material may also be different, and the ratio of the volume of the vial and the volume of the polymeric material may be any ration of between 1 ,000,000:1 to 10:1 . The polymeric material may be any polymeric material as described elsewhere herein.

When the retaining material is arranged as a phase at a flat bottom of supporting means, the maximum thickness of the retaining material may be any suitable thickness such as between 0.00001 to 1 cm, e.g. between 0.0005 and 0.8 cm, such as between 0.0001 and 0.6 cm, e.g. between 0.005 and 0.4 cm, such as between 0.01 and 0.2 cm, e.g. between 0.05 and 0.1 cm, such as between 0.01 and 0.05 cm. In an embodiment the polymeric material (e.g. of PDMS) has an optimal thickness of about 0.02 cm.

The device of the present invention may also be used as a storage means, such that the compound may be stored in the device together with a first solvent or the compound may be stored in the device retained in the polymeric material after the first solvent is evaporated off, optionally the retained compound may be re-suspended in a second solvent before and/or during storage. Optionally, water may be added and a protecting layer of ice can then easily be obtained upon freezing.

It is within the meaning of the present invention that more than one compound determined by different chemical structures may be retained simultaneously within the polymeric material, e.g. at least two compounds, such as at least three compounds, e.g. at least four compounds, e.g. at least five compounds.

When two or more compounds having different chemical structures are simultaneously retained by the polymeric material of a vial, one or more e.g. all of these compounds may be re-dissolved in a solvent. The type of solvent may also be selected such that not all compounds are re-dissolved in the solvent. When one or more compounds are re-dissolved in a solvent, this solvent including the re-dissolved compounds can be removed from the vial and one or more or the remaining compounds can be re- dissolved in another type of solvent.

In an embodiment at least one detector means is embedded within and/or located on the retaining material. "Embedded within" is to be understood as located inside a volume of non-fibrous polymeric material and/or inside a volume made of very short fibrous polymeric material, whereas "located on" can mean located on only the outermost surface of the layer or volume of the retaining material and/or located on fibre of the retaining material even though these fibre may be located inside the overall volume of the retaining material. This means that when the detector means is located on the fibre, then the detector means need not be located at the outermost surface of the layer.

Detector means can be absorbance indicators, fluorescence indicators, luminescence indicators, colour shift indicators, NIR indicators, antibodies, electrodes and voltametric detectors or a combination hereof. These detectors might be used to determine the presence of one or several analytes or it might be used for quantification of specific analytes or relevant sum-parameters. One example would be the inclusion of two or more electrodes within the polymer in order to detect changes in the conductive properties of the polymer upon absorption of specific analytes/compounds. Another example would be the inclusion of reactive chemicals or antibodies that upon binding or reaction give a change in colour, absorbance, luminescence and/or fluorescence.

In an embodiment a metal stripping agent (e.g. 4-(pyridyl-2-azo)resorcinol (PAR) is integrated into a metal conducting solgel. The agent will bind specific metals and at the same time change its optical appearance, which can be utilized for visual or instrumental readings. Such a stripping agent can be considered a chemical detector system.

In an embodiment one end of an optical fiber is integrated into a silicone elastomer (e.g. from below), pushed as a needle into the polymer or placed just at the outer surface of the polymer (e.g. from above using an autosampler). Light within e.g. the UV-range might be send through the fiber and into the polymer, whereas the light returning from the polymer is send to a suitable detector for the measurement of e.g. fluorescence lifetime profiles and intensive optical properties (e.g. fluorescent ratios). Such a system can be optimized to for instance polycyclic aromatic hydrocarbons and fluorescent toxins. One specific feature of this system is that proteins that are known to interfere fluorescence measurements will not enter the polymer and thus not interfere. Such a system might also be extended by doping the polymer with a suitable fluorescent reagent in order to detect and/or quantify e.g. nucleic acid, DNA, proteins, drugs and/or pesticides.

In an embodiment a surface plasmon resonance sensor constitutes the bottom of the vial on which the retaining polymer is placed. When the analytes are retained by the polymer, they are brought into the detection range of the sensor, they have a high concentration and the polymer provides standardized measurement conditions and ensures that particles and proteins are not entering the polymer. Alternatively, the surface of the sensor is modified in order to maximize surface adsorption of the analytes (e.g. with antibodies) and the polymer serves then as a conducting medium for the analytes and as a barrier for interferences (proteins, humic acids, particles etc.)

In an embodiment a microcuvette constitutes the lower part of the vial. The microcuvette is filled with silicone and the retained analytes detected by e.g. fluorescence and absorbance measurements. The polymer might again have been doped with various fluorescent dyes in order to extend the range of target analytes and the polymer serves again as a barrier for interfering proteins and particles.

Further features of the device is described herein below in the description of the method comprising retaining a compound in a polymeric material as well as in the description of the way the device can be used.

The device as described herein is designed to serve two main objectives/functions:

1. Evaporation of solvent extract to substantially dryness without loss of compound/analyte as the analyte is dissolved/retained in the polymeric material and the subsequent re-dissolution into a known e.g. a small solvent volume (e.g. 50 μl_). The reduction of extract volume by more than one order of magnitude will result in significantly lowered detection limits.

2. Change of sample solvent (i.e. "Solvent switching"). After evaporation of the first solvent the compounds/analytes can be re-dissolved from the polymeric material (e.g. PDMS) into a second solvent. The volume of this second solvent can be much lower than the volume of the original extract or than the volume of the first solvent. The added second solvent volume can be accurately and precisely controlled and it is possible to use a solvent different from the original one (solvent switching). The latter is often needed in order to satisfy the injection requirements of a given analytical instrument or procedure.

Method of isolating, concentration and identification of compounds

In another aspect the invention relates to a method for isolating and/or concentrating at least one compound, the method comprises • providing at least one compound,

• dissolving and/or suspending the at least one compound in a first solvent,

• providing a polymeric material which is capable of retaining the at least one compound,

• retaining the at least one compound dissolved and/or suspended in the first solvent in or on the polymeric material,

• evaporating at least a part of the first solvent, obtaining the at least one compound retained within and/or on the polymeric material.

In a preferred embodiment the invention relates to a method for isolating and/or concentrating at least one compound, the method comprises

• providing a liquid sample comprising at least one compound, where said liquid is a first solvent, or providing a non-liquid sample comprising at least one compound,

• dissolving and/or suspending the at least one compound in said non-liquid sample in a first solvent to obtain a liquid sample comprising the at least one compound,

• providing a retaining material which is capable of retaining the at least one compound,

• bringing said liquid sample comprising the at least one compound in contact with said retaining material,

• evaporating substantially all of said first solvent,

• hereby retaining substantially all of the at least one compound dissolved and/or suspended in the first solvent in or on the retaining material, and

• hereby obtaining the at least one compound retained within and/or on the polymeric material. The steps of providing at least one compound and dissolving and/or suspending this at least one compound in a first solvent need not be a two-step process, the compound can be dissolved/suspended in a solvent when this solution is obtained e.g. the solution can be a solution which is to be inspected for the presence and/or concentration of compounds.

In an embodiment the working principle may be that compound(s)/analyte(s) are dissolved in a first solvent and remain there i.e. remain in the first solvent until the first solvent is almost fully evaporated. At this moment the analyte(s) enter the retaining material, instead of evaporating. Hereby the solvent phase may almost be removed before the analyte(s) are transferred to and/or into the retaining material.

Generally the compounds to be isolated can be obtained within a liquid or slurry i.e. a buoyant sample e.g. a liquid sample obtained directly from a source which is to be examined in respect of the analyte in question i.e. the predetermined analyte. This buoyant sample may be further diluted by a first solvent, also the sample may be pretreated e.g. filtered before the sample is subjected to the method described herein.

Also the analyte may be obtained in a substantially dry condition e.g. as part of a soil sample, the amount of the analyte may be partly or fully extracted into a first solvent. This first solvent with the analyte can be analysed by the method described herein. The material obtained in substantially dry conditions may be any kind of a soil material including soft material such as sand and hard material such as stone or rock, also other materials can be tested e.g. slags from different industries. These hard materials may be subjected to a pretreatment before the sample is tested. Pretreatment may include e.g. grinding, extraction and filtration.

The device and method as presented herein allows for a selective reversible retention of one or more analytes during solvent evaporation. Also the device and method allows for a subsequent elution into e.g. a small and well known volume of a second solvent with the main purpose to maximize recovery during reduction of solvent volume and during solvent change. In an embodiment the method further comprises the step of direct detection of the at least one compound within and/or on the retaining material. The meaning of the terms "within" and "on" is described elsewhere herein.

The at least one compound can be detected and/or measured directly within or on the polymeric material using different kinds of one or more of the detection principles selected from the group of absorbance, fluorescence, luminescence, colour shift, NIR, colour shift upon reaction with antibodies and/or within polymer or matrix-assisted laser desorption/ionisation-time of flight mass spectrometry (MALDI-TOF MS).

In another embodiment direct detection of a compound can be performed due to at least one detector embedded within and/or located on the polymeric material. The detector can be electrodes and/or voltametric detectors.

In a further embodiment the method further comprises the step of re-dissolving and/or re-suspending the at least one compound in a second solvent. Hereby the compound(s) retained by the retaining material is released from the retaining material and is obtained within the second solvent. The compound(s) can be redissolved and/or re-suspended into a second solvent by simple addition of the second solvent to the vial including the retaining material retaining the compound(s). The volume of this second solvent can be much smaller compared to the total volume of the first solution before evaporation of the first solution, hereby leading to increased concentration of the at least one compound.

In another embodiment the method comprises the step of performing a biological or chemical assay on and/or close to the polymer surface and/or in a small volume above the polymer. Hereby the at least one compound can be measured and/or studied with assays above the polymeric material and/or at the surface of the polymeric material. Such assays can aim at biological or chemical responses.

The assay may for example be springtail (Folsomia Candida) toxicity tests, Daphnia magna toxicity test, Ames test for mutagenicity, Microtox™toxicity test or the Kastle- Meyer wet chemistry test for haemoglobin. In a further embodiment the biological responses may be a response determined to be toxicity, change of metabolism, stimulation of growth, change of endocrine system, stimulation or inhibition of reproduction, genotoxicity, mutagenicity, change in behaviour, induction or suppression of specific genes. The biological responses may for example be lethality, as in the springtail 96h acute toxicity test or mutagenic potential, as in the Ames test.

The chemical responses can be at least one chemical reaction leading to colour shift, pH shift and/or the formation of fluorescent compounds, or a combination thereof. The chemical responses can be derivatisation of compounds aimed at improved instrumental analysis by for instance gas chromatography. As an example, amines may be derivatised by a substitution reaction with dansyl chloride to form fluorescent dansyl amides. As another example, organotin compounds may be ethylated with tetraethylborate in order to make them separable and possible to analyze with gas- liquid chromatography (GC).

In an embodiment the method also comprises the step of measuring the concentration of the at least one compound re-dissolved and/or re-suspended in the second solvent. The concentration of the re-dissolved and/or re-suspended compound can be measured by methods known by the skilled person including (high performance) liquid chromatography, gas chromatography and capillary electrophoresis coupled to e.g. absorbance detector, flame ionisation detector, mass selective detector or electron capture detector.

When performing the evaporation step of the method as described herein the main part of the first solvent is evaporated from the retaining material after the first solvent including the compound(s) of interest is brought into contact with the retaining material. The time to wait before initiating the evaporation is generally insignificant. However in cases where the compound is unstable/degraded in the solvent the time to evaporation is of obvious importance.

When performing the evaporation it is preferred that substantially all or all of the first solvent can be evaporated from the retaining material. Preferred is when at least 90% of the first solvent is evaporated, such as at least 91%, e.g at least 92%, such as at least 93%, e.g at least 94%, such as at least 95%, e.g at least 96%, such as at least 97%, e.g at least 98%, such as at least 98.5%, e.g at least 99%, such as at least 99.1 %, e.g at least 99.2%, such as at least 99.3%, e.g at least 99.4%, such as at least 99.5%, e.g at least 99.6%, such as at least 99.7%, e.g at least 99.8%, such as at least 99.85%, e.g at least 99.9%, such as at least 99.95%, e.g at least 99.99%. More preferred is when at least 98% of the first solvent evaporates. Further preferred is when at least 98.5% of the first solvent evaporates. Most preferred is when at least 99% of the first solvent evaporates.

As the first solvent evaporates the at least one compound in the solution can become located within and/or on the retaining material and may hereby be retained by the retaining material. The mechanism of retention in the retaining material is absorption (i.e. dissolution) or ion exchange. The mechanism of retention on the retaining material is adsorption (i.e. by Van der Waal forces and/or by the formation of compound specific chemical bond).

In an embodiment the evaporation of the first solvent is performed by passive evaporation to the atmosphere and or to a cold trap and/or by subjecting the vial and/or supporting means and/or the first solvent and/or retaining material to gas flow or to laminar gas flow and/or heating the vial and/or supporting means and/or the first solvent and/or retaining material. The gas may be air or nitrogen or argon or a combination thereof.

In another embodiment the polymeric material of the retaining material can be selected from the group of polysiloxanes, polyethylene, polypropylene, latex, polybutadiene, polyisobutylene, polyurethanes, polyacrylate, polycyanoacrylate, polyvinyl acetate, polyethylene glycol, polymers incorporation ion-exchange resins, polystyrene divinylbenzene or a combination thereof.

Examples of polymer blends which can be used as a polymeric material as described herin: (1 ) low-density polyethylene with polydimethylsiloxane and ethylene vinyl acetate, (2) poly(methyl methacrylate) with poly(vinylidene fluoride), (3) polystyrene with polybutadiene and p-(hexafluoro-2-hydroxyisopropyl)styrene.

The physical form of the polymeric material is described elsewhere herein. In a preferred embodiment the retaining material is located as a polymeric phase at the inner bottom of a vial. The retaining phase allows the at least one compound to be adsorbed and/or absorbed by the retaining material and hereby retained within and/or on the retaining material.

The first solvent from where the at least one compound is to be concentrated, purified and/or analysed may be any liquid including, but not limited to, an extract. Extracts can be liquids which may be obtained from industrial processes e.g. process water and waste water; obtained from nature e.g. from sea, stream water and soil; obtained from households e.g. waste water; obtained from living organisms e.g. from animals and plants; etc.

In a further embodiment the at least one compound of interest can be selected from the group of volatile, semi-volatile or non-volatile organic, inorganic or elemental substances.

The at least one compound of interest can also be selected from the group of halogenated organic chemicals, monoaromatic organic chemicals, polyaromatic organic chemicals, organometals, alkanes, pharmaceuticals, flameretardants, plasticisers, pesticides, vitamines, warfareagents, pigments, flavors, natural toxins, active ingredients in herbal medicine, preservators, legal and illegal drugs, biocides or a combination thereof.

Furthermore the at least one compound of interest may have at least one functional group selected from the groups of Alcohol, Thiol, Amine, Alkane, Alkene, Alkyne, Carboxylic acid, Carboxylic acid ester, Carboxylic thioester, Ether (oxygen) , Thioether, Aldehyde, Ketone, Thioketone, Epoxide, Peroxide, S- heterocyclic (saturated/unsaturated), N-heterocyclic (saturated/unsaturated), O-heterocyclic (saturated/unsaturated), Amide, Nitrile, Oxime, Thiocyanate, Cyanamide, Nitro, Nitrate ester, Diazo, Organohalide, Organometallic, Organophosphate ester, Thiophosphate ester, Phosphonic acid, Phosphinic acid, Sulfonic acid, Sulfate ester, Amino acid, Cyanate or a combination thereof.

Also the at least one compound of interest can be selected from the group of alfa-HCH, beta-HCH, gamma-HCH, Where "HCH" means Hexachlorocyclohexane. Compounds of interest can also be selected from the group of PCB-101 (2, 2', 4, 5, 5'- pentachlorobiphenyl), PCB-105 (2,3,3',4,4'-pentachlorobiphenyl), PCB-1 18 (2,3',4,4',5- pentachlorobiphenyl), PCB-128 (2,2',3,3',4,4'-hexachlorobiphenyl), PCB-138 (,2',3,4,4',5'-hexachlorobiphenyl), PCB-149 (2,2',3,4',5',6-hexachlorobiphenyl), PCB- 153 (2,2'_!4_!4'_!5,5'-hexachlorobiphenyl)_! PCB-156 (2,3,3',4,4',5-hexachlorobiphenyl), PCB-170 (2,2',3,3',4,4',5-heptachlorobiphenyl), PCB-180 (2,2',3,4,4',5,5'- heptachlorobiphenyl), PCB-198 (2,2',3,3',4,5,5',6-octachlorobiphenyl), PCB-28 (2,4,4'- trichlorobiphenyl), PCB-3 (4-chlorobiphenyl), PCB-31 (2,4',5-trichlorobiphenyl), PCB-40 (2,3',3,3'-tetrachlorobiphenyl), PCB-52 (2,2',5,5'-tetrachlorobiphenyl), where "PCB" means Polychloronated biphenyl.

Compounds of interest can also be selected from the group of Hexachlorobenzene, o'p-DDE (1 ,1 -dichloro-2-(o-chlorophenyl)-2-(p-chlorophenyl)ethene), o'p-DDT (1 ,1 ,1 - trichloro-2-(o-chlorophenyl)-2-(p-chlorophenyl)ethane), p'p'-DDD (1 ,1 -dichloro-2,2-di(4- chlorophenyl)ethane), p'p-DDE (1 ,1 -dichloro-2,2-di(4-chlorophenyl)ethene), pp'-DDT (1 ,1 ,1 -Trichloro-2, 2-di(4-chlorophenyl)ethane), Phenanthrene, Anthracene, Fluoranthene, Pyrene, Benz[a]anthracene, Chrysene, Benzo[b]fluoranthene, Benzo[k]fluoranthene, Benzo[a]pyrene, lndeno[1 ,2,3-cd]pyrene.

An example of a volatile substance which can be isolated by the method described herein is nicotine, esotheric oils from plants, volatiles emitted by fungi and mold and also non-identified natural compounds with a specific effect on organisms.

The compounds of interest as listed above can be retained solitary by a retaining material, or the compounds as listed can be retained several types together by a retaining material, where the retaining material may be any one as described elsewhere herein.

When several types of compounds are retained together by a retaining material, one or more, but optionally not all compounds may be resuspended/redissolved together in a second solvent. Compounds still retained by the polymeric material may one or more at a time be resuspended/redissolved together in a third solvent. The third solvent may be any one described herein as first or second solvent.

In an embodiment the first and/or second solvent can be selected from the group of alkane, arene, alkylhalide, ketone, ether, alcohol, ester, nitrile, carboxylic acid, amine, nitro, amide, sulfoxide, thioketone, water, alkene, arylhalide, super critical fluid or a mixture of these.

Also the first and/or second solvent can be selected from the group of isooctane, toluene, dichlormethane, acetone, diethylether, methanol, ethylacetate, acetonitrile, glacial acetic acid, diethylamine, nitromethane, dimethylformamide, dimethylsulfoxide, carbon disulfide, limonene, chlorobenzene, super critical carbon dioxide or a mixture of these.

A third and subsequent solvent may be selected among the solvents mentioned above.

In an embodiment the working principle of the method can be described as: A small volume of a polymeric material at the bottom of a conical vial can be used to retain at least one compound during solvent evaporation of sample extracts. The compounds in the polymeric material can subsequently be re-dissolved with a second solvent or with a known volume of a first solvent. The method features very good control of final extract volume even down to very small volumes, the possibility to switch solvents and it avoids the use of keeper solvents.

The method in one embodiment is thus based on the coupling of the following 2 principles:

1. Using a small volume (e.g. 3 μl) of a polymeric material (e.g. PDMS) to retain at least one compound from a first volatile liquid solvent during the final phase of its evaporation. 2. The fast release of the retained at least one compound from the polymeric material upon the addition of a small volume of a first or second solvent of choice (e.g. 20 μl).

In a preferred embodiment, the device comprises a glass vial with a small polymeric material phase attached to the lower part of the inner wall.

Micro- and nanoliter applications

The miniaturization of analytical methods includes the application of micro arrays, nano vials, the laboratory on a chip and the μ-TAS system. The surface area to volume ratio increases with decreasing dimensions, and evaporative losses of solvents and analytes are thus a particular challenge when handling very small sample volumes e.g. nanoliters and microliters. The described invention can be applied to retain, concentrate and focus analytes prior to instrumental analysis. Examples of such applications: (1 ) The solvent of a micro-extract can be evaporated, the analytes retained in a nanoliter volume of polymer or other retaining material and subsequently dissolved in a second solvent. (2) The analyte can be retained in a nanoliter volume of polymer or other retaining material where it undergoes a chemical reaction and/or is detected as described elsewhere. The polymer or other retaining material acts in this way as a non-volatile solvent. (3) The solvent of a micro-extract can be evaporated and the analytes retained in a nanoliter volume of polymer or other retaining material. The analytes are in this manner focused in a small volume and area, which can be utilized for instance for MALDI TOF.

Production of the device

A further aspect of the invention relates to a method for the production of a device suitable for isolating, concentrating and/or determining at least one compound, the method comprises • providing a supporting means,

• providing at least one retaining material comprising a polymeric material in the form of a polymer solution and/or a polymer dispersion optionally further including a non-polymeric material, where the polymeric and/or non-polymeric material is capable of retaining at least one compound when the retaining material and/or compound is in substantially dry condition,

• placing the polymer solution and/or polymer dispersion optionally further including a non-polymeric material on or within the supporting means,

• securing the polymer solution and/or polymer dispersion optionally further including a non-polymeric material on or within the supporting means, and hereby

• obtaining a device comprising a supporting means with a polymeric material secured on or within the supporting means.

Preferably, in the step of securing the polymer solution and/or polymer dispersion optionally further including a non-polymeric material on or within the supporting means, this solution/dispersion of the retaining material is located in the area from where the solvent of the solution/dispersion will evaporate if subjected to evaporation.

The step of securing the retaining material to the supporting means can be an inherent process occurring at the time the solvent of the solution/dispersion of the retaining material is evaporated.

In general a polymer is a chemical compound in which at least thousands of repeating structural units (monomers) are covalently linked. A solution is a molecularly homogenous mixture of one or more substances and a dispersion is a system consisting of particulate matter (i.e. mainly microscopic, but not molecular, particles) evenly distributed in a medium.

The supporting means may be any supporting means as described elsewhere herein, and the retaining material may be any retaining material including polymeric material as described elsewhere herein.

In an embodiment the retaining material is physically placed on or within the supporting means and/or secured to the supporting means by evaporative deposition of the polymer solution and/or the polymer dispersion.

In a preferred embodiment the solution/dispersion of the retaining material located within the supporting means is subjected to evaporation such that the retaining material is located in the area from where the solvent of the solution/dispersion evaporates. Hereby the retaining material is located in the area from where the last part of the solvent with the analyte will evaporate when the device is used for isolation of at least one analyte in a sample.

When a retaining material is to be located within a supporting means e.g. a vial, the vial may be oriented in the orientation expected to be used later on when the first solvent is to evaporate leaving the at least one compound of interest in or on the polymeric material as described elsewhere herein. After the vial is oriented, a retaining solution and/or retaining dispersion may be located within the vial and the volatile solvent/dispersion medium subsequently evaporated. The retaining material may become connected to the vial in a specific location of the vial e.g. in the bottom of a vial having a pointed inner bottom. Hereby it can be ensured that the polymeric material is present at the exact location where the evaporation is terminated when the vial is used.

No pre-treatment of the vial is necessary before the retaining material is to be located within the vial as long as the vial is clean.

The retaining material to be deposited in the vial may be obtained as a polymer solution based on 0.01 to 1 g polymer per ml solvent. Preferred is between 0.025 to 0.9 g polymer/ml solvent, such as between 0.5 to 0.8 g, e.g. between 0.75 to 0.7 g, such as between 0.1 to 0.6 g, such as between 0.15 to 0.5 g, e.g. between 0.2 to 0.4 g, such as between 0.25 to 0.35 g, such as about 0.3 g. A non-polymeric material may be included in the described amounts or may be further added to the solution.

As an example the polymer solution may be e.g. 0.3 g PDMS/ml (pentane).

The polymer solution is prepared by e.g. vigorous handshaking and sonication of a polymer and solvent mixture. See also Example 1. Optionally, 0.03 g activated carbon can be added to the PDMS pentane mixtures in order to prepare a composite of PDMS and activated carbon.

The device can be produced by evaporative deposition of the polymer, which ensures the correct location and geometry that is needed for optimized evaporative enrichment of the analytes.

In an embodiment the device can be produced from two components: (1 ) a glass for holding or supporting the extract and for focusing the final evaporation process of the first solvent to a small volume at the lower tip of the glass. (2) a retaining material e.g. a polymeric material that is placed in the lower tip of the glass for retaining the at least one analyte during and after solvent evaporation. These two components can be varied. In a preferred embodiment they can fulfil the following requirements:

1. Injection vial/evaporation glassware with sufficient total volume (>10 μl_) and a tapered, narrowing or conical geometry in the bottom, to assure that during the evaporation of the first solvent the last remaining drop of solvent is in good contact with the retaining material. 2. Retaining material e.g. polymeric material that can form an insoluble thick layer or lump in the bottom of the vial and connected to the glass surface. In this embodiment an important feature is the amount and position of the polymeric material in the bottom of the evaporation glass.

In a preferred embodiment the retaining material is located in the vial by locating a solution/dispersion of the retaining material in a solvent in the vial. The solution/dispersion is subjected to evaporation e.g. by heating and the solvent evaporates. The retaining material will hereby be located in the bottom of the vial.

A further aspect of the invention relates to use of the device as described herein for isolating, concentrating and/or identification at least one compound.

Another aspect of the invention relates to use of the method as described herein for concentrating and/or identification at least one compound.

In an embodiment the device or method is used for analysing liquids which may be obtained from industrial processes e.g. process water and waste water; obtained from nature e.g. from sea, stream water and soil; obtained from households e.g. waste water; obtained from living organisms e.g. from animals and plants; etc.

Detailed description of the drawings

Fig. 1 illustrates the use of the device described herein for concentrating a compound or an analyte. The figure also illustrates one design of the device. The vial has a pointed bottom where the polymeric material optionally further comprising a non- polymeric material is located in the position of the vial from where the last part of the solvent will evaporate. The sample or sample extract (the first solvent) to be evaporated containing the analyte(s)/compound(s) is placed in a vial (a) and the first solvent is evaporated e.g. under a gentle stream of nitrogen gas. After evaporation of the solvent analyte(s) are retained in the polymer (b) and can be recovered in a new volume of the first solvent and/or of a second solvent (c). The working principle of a device according to the present invention can be illustrated as in Figure 1. In a) the polymeric material is located in the volume closest to the bottom of the vial (the polymeric material is a lump at the bottom of the vial) and the sample extract including a first solvent is located in the vial above the polymeric material. The first solvent is evaporated, here illustrated by passing a nitrogen flow across the surface of the sample extract. In b) all the first solvent is evaporated from the vial leaving the at least one analyte retained within the polymeric material at the bottom of the vial. In c) a small volume of the first or a second solvent is added and the at least one analyte is released from the polymeric material and into the second solvent. The Figure also illustrates an example of a device according to the present invention. A vial is including a polymeric material where the polymeric material preferably is located in the bottom of a tapered tip.

Fig. 2. Results of recovery of several polychlorinated biphenyls (CB-x), hexachlorobenzene (HCB) and different organochlorine pesticides in vials denoted "Aluvial" produced according to the present invention as compared to traditional vials without any retaining material. The extract solvent was evaporated until dryness with a laminar nitrogen flow and the nitrogen flow continued for another 30 (upper panel) and 300 minutes (lower panel) in order to test the robustness of the method. High recoveries were observed for the vials produced according to the present invention, whereas substantial evaporative loss was observed for several analytes in the untreated vials. Note the logarithmic scale. Further information is presented in Example 1 and 2.

Fig. 3. The figure illustrates different preferred embodiments of the device and the localisation within the vial of the retaining material. The vial (1 ) includes a retaining material (2). The device may be a keeper vial. The retaining material (2) of the vial (1 ) is located in the bottom volume of vials/tubes of different designs. The retaining material may be a polymeric material optionally further comprising a non-polymeric material. The figure indicates the shape of the inner surface of the vials/tubes (1 ) used as supporting means of the device of the present invention, thus the form of the outer surface may be different. The retaining material is consolidated and focused exactly at, and below, the area in the vials/tubes from where the last of the volatile solvent will evaporate during the method described in this invention. The retaining material is focused in the process of manufacturing the device by evaporation of a solvent used to dissolve/disperse the retaining material.

Examples

Example 1

Production of the device (evaporative deposition of PDMS)

1. Silastic™ silicone (Medical adhesive, Dow Corning) (a high purity grade "self- curing" PolyDimethylSiloxane [PDMS]) is dispersed in n-pentane by vigorous handshaking and sonication, the dispersion is diluted to 0.3g PDMS/ml pentane.

2. 10 μl of this polymer dispersion is carefully placed in the bottom of 1.1 -ml crimp top tapered vial (Purchased from: Chromacol Ltd., Welwyn Garden City, UK [Part Number 1.1 -CTVG]).

3. The pentane is evaporated off at room temperature.

4. The PDMS is allowed to cure (vulcanize/cross-link) in the vials for at least 72h in 100% relative humidity.

5. The devices are rinsed with pentane and stored in "air and diffusion"-tight containers until used.

Example 2

The function of the device

To demonstrate the two main objectives/functions stated herein above, and the function of the vials, the following experiment was performed.

1 . Ten devices (vials), prepared as described in Example 1 and ten identical vials without polymer (i.e. as commercially available), were rinsed with n-hexane for more than 10 minutes immediately before use. After rinsing, the hexane was decanted.

2. The sample extract was prepared by adding 25 μl_ of a 40ng/ml solution of the analytes (see Fig 2 for the description of the analytes tested, the analytes are mentioned elsewhere herein as "PCB-xx" where "xx" indicates the number) and 1 ml of n-hexane giving a concentration of about 1 ng/ml. This is a very low analyte concentration that requires up-concentration prior to analysis.

3. The solvent was evaporated off under a gentle flow of nitrogen.

4. Approximately 30 minutes after the last solvent has evaporated, five vials from each series were collected and to each was added 50 μl_ octane spiked with internal standard.

5. Approximately 300 minutes after the last solvent has evaporated, the remaining five vials from each series were collected and to each was added 50 μl_ solvent octane spiked with internal standard. 6. The vials were capped and stored in freezer until analyzed by dual column GC- ECD.

The results of this experiment are presented in Figure 2. The analytes tested were recovered close to 100% for most of the compounds when using the device as described herein. When using a vial without the polymeric material, the recovery of the analytes was lower than when using a vial with a polymeric material according to the invention described. From this experiment it can be concluded that the device described herein has superior performance compared to known techniques when evaporating samples to dryness.

Example 3

Round bottom test tubes of glass (12x75 mm) were used as supporting means. A dispersion of Silastic silicone pre-polymer was prepared in pentane as described in example 1 . Activated carbon particles (untreated powder 100-400 mesh) were added to the dispersion at 0.03 g/ml. Various volumes of the resulting dispersion were added to the tubes in order to deposite the composite of 1 part of activated carbon embedded in 10 parts of PDMS. Devices with several composite volumes were prepared.

The prepared devices will be tested for their suitability to retain volatile organic chemicals such as naphtalene, nicotine, benzene, toluene and alkanes. This approach requires a highly volatile first solvent with a boiling point that is well below the boiling point of the analytes. The sorptive properties of the composite (PDMS with activated carbon) and the ability of the PDMS to conduct non-polar analytes were already tested with 10 polycyclic aromatic hydrocarbons (PAHs). The PDMS was found to be a good conducting medium for PAHs and an excellent physical support for the activated carbon particles that provides a smooth and stable surface of the retaining material. The activated carbon provided very high sorptive capacity and the addition of activated carbon into the PDMS clearly enhanced the analyte retention.

Claims

1. A device comprising

• a supporting means capable of containing a liquid, and • a retaining material comprising a polymeric material,

• wherein said retaining material is located in the lower part of the supporting means from where the last part of a liquid will evaporate if a liquid contained by the supporting means is subjected to evaporation,

• said retaining material has a shape determined by the evaporation of a solvent into which said retaining material is dissolved or dispersed, and

• wherein the retaining material is capable of retaining at least one compound, i. when liquid is removed by evaporation and/or ii. in absence of any volatile solvent and/or iii. when the polymeric material and/or the at least one compound is in a substantially dry condition.

2. The device according to claim 1 , wherein the supporting means is made of a material selected from the group of polymers, glass, ceramics, porcelain, metal or a combination thereof.

3. The device according to any of the preceding claims, wherein the supporting means is made of a material with insignificant retention and/or permeability of the at least one compound.

4. The device according to any of the preceding claims, wherein the supporting means comprises a material which can withstand a solvent used for dissolving or resolving the at least one compound before and/or after the at least one compound is retained by the polymeric material.

5. The device according to any of the preceding claims, wherein the supporting means has a form selected from the group of cylinder, glass, ampoule, canister, pot, basin, jar, pitcher, cup, bottle, vial, test tube, flask, crucible, tube, beaker, multi well plate, micro well plate or a plate with nanoliter small holes.

6. The device according to claim 5, where the supporting means further is capped or uncapped and/or conical, round bottomed, tapered or flat bottomed.

7. The device according to any of the preceding claims, wherein the supporting means has at least one pointed inner bottom and/or at least one flat bottom.

8. The device according to any of the preceding claims, wherein the supporting means has an inner volume of less than 1 ,000 L.

9. The device according to any of the preceding claims, wherein the retaining material is a polymeric material.

10. The device according to claim 9, where said polymeric material is selected from the group of polysiloxanes, polyethylene, polypropylene, latex, polybutadiene, polyisobutylene, polyurethanes, polyacrylate, polycyanoacrylate, polyvinyl acetate, polyethylene glycol, polymers incorporation ion-exchange resins, polystyrene divinylbenzene or a combination thereof.

1 1. The device according to any of claims 9-10, wherein the retaining material further comprises a non-polymeric material.

12. The device according to claim 1 1 , wherein said non-polymeric material is selected from the group of activated carbon, antibodies, Tenax, Florisil, Alumina or a combination thereof.

13. The device according to any of the preceding claims, wherein the retaining material is non-volatile.

14. The device according to any of the preceding claims, wherein the retainin material is insoluble in at least one solvent useful for dissolving or resolving the at least one compound.

15. The device according to any of the preceding claims, wherein the retaining material is supported by the supporting means due to adhesion of the retaining material to the supporting means.

16. The device according to any of the preceding claims, wherein the retaining material occupy a volume corresponding to 0.001 to 10 % of the internal volume of the supporting means.

17. The device according to any of the preceding claims, wherein the retaining material at the centre of the material has a thickness of at least 0.5 μm.

18. The device according to any of the preceding claims, wherein at least one detector means is embedded within and/or located on the retaining material.

19. The method according to claim 18, wherein the at least one detector means is selected from the group of absorbance indicators, fluorescence indicators, luminescence indicators, colour shift indicators, NIR indicators, antibodies, electrodes and voltametric detectors or a combination hereof.

20. A method for isolating and/or concentrating at least one compound, the method comprising

• providing a sample comprising at least one compound, said sample being i. a liquid sample comprising at least one compound, where said liquid is a first solvent, or ii. a non-liquid sample comprising at least one compound,

• dissolving and/or suspending said non-liquid sample comprising at least one compound in a first solvent to obtain a liquid sample comprising the at least one compound,

• evaporating substantially all of said first solvent,

• obtaining the at least one compound retained within and/or on the retaining material.

21 . The method according to claim 20, further comprising the step of re-dissolving and/or re-suspending the at least one compound in a second solvent.

22. The method according to claim 21 , further comprising the step of direct detection of the at least one compound within or on the retaining material.

23. The method according to claim 22, wherein the direct detection is performed by one or more of the detection principles selected from the group of absorbance, fluorescence, luminescence, colour shift, NIR, colour shift upon reaction with antibodies and/or within polymer or matrix-assisted laser desorption/ionisation- time of flight mass spectrometry (MALDI-TOF MS).

24. The method according to claim 22 or 23, wherein the direct detection is performed due to at least one detector embedded within and/or located on the retaining material.

25. The method according to claim 24, wherein the detector is electrodes and/or voltametric detectors.

26. The method according to any of claim 20 to 25, further comprising the step of performing a biological or chemical assay on and/or close to the surface of the retaining material or in a small volume above the retaining material.

27. The method according to claim 26, wherein the biological responses is a response determined to be toxicity, change of metabolism, stimulation of growth, change of endocrine system, stimulation or inhibition of reproduction, genotoxicity, mutagenicity, change in behaviour, induction or suppression of specific genes.

28. The method according to claim 26, wherein the chemical responses is at least one chemical reaction leading to colour shift, pH shift and/or the formation of fluorescent compounds, or a combination thereof.

29. The method according to claim 26, wherein the chemical responses is a derivatisation of compounds aimed at improved instrumental analysis by for instance gas chromatography.

30. The method according to any of claims 21 to 29, further comprising the step of measuring the concentration of the at least one compound re-dissolved and/or re-suspended in the second solvent.

31 . The method according to any of the claims 20 to 31 , wherein the evaporation is performed by heating, cooling, laminar air flow, flow of a carrier gas, nitrogen flow, laminar nitrogen flow, vacuum enhanced evaporation, or a combination thereof.

32. The method according to any of the claims 20 to 32, wherein the retaining material is a polymeric material.

33. The method according to claims 32, wherein the polymeric material is selected from the group of polysiloxanes, polyethylene, polypropylene, latex, polybutadiene, polyisobutylene, polyurethanes, polyacrylate, polycyanoacrylate, polyvinyl acetate, polyethylene glycol, polymers incorporation ion-exchange resins, polystyrene divinylbenzene or a combination thereof.

34. The method according to any of the claims 32 to 33, wherein said retaining material further comprises a non-polymeric material.

35. The method according to claim 34, wherein said non-polymeric material is selected from the group of activated carbon, antibodies, Tenax, Florisil, Alumina or a combination thereof.

36. The method according to any of the claims 20 to 35, wherein the compound is selected from the group of volatile, semi-volatile or non-volatile organic, inorganic or elemental substances.

37. The method according to any of the claims 20 to 36, wherein the compound is selected from the group of halogenated organic chemicals, monoaromatic organic chemicals, polyaromatic organic chemicals, organometals, alkanes, pharmaceuticals, flameretardants, plasticisers, pesticides, vitamines, warfareagents, pigments, flavors, natural toxins, active ingredients in herbal medicine, preservators, legal and illegal drugs, biocides or a combination thereof.

38. The method according to any of the claims 20 to 37, wherein the at least one compound has at least one functional group selected from the groups of Alcohol, Thiol, Amine, Alkane, Alkene, Alkyne, Carboxylic acid, Carboxylic acid ester, Carboxylic thioester, Ether (oxygen) , Thioether, Aldehyde, Ketone,

Thioketone, Epoxide, Peroxide, S-heterocyclic (saturated/unsatu rated), N- heterocyclic (saturated/unsaturated), O-heterocyclic (saturated/unsaturated), Amide, Nitrile, Oxime, Thiocyanate, Cyanamide, Nitro, Nitrate ester, Diazo, Organohalide, Organometallic, Organophosphate ester, Thiophosphate ester, Phosphonic acid, Phosphinic acid, Sulfonic acid, Sulfate ester, Amino acid,

Cyanate or a combination thereof.

39. The method according to any of the claims 20 to 38, wherein the at least one compound is selected from the group of alfa-HCH, beta-HCH, gamma-HCH, PCB-101 , PCB- 105, PCB- 1 18, PCB- 128, PCB- 138, PCB-149, PCB- 153, PCB-

156, PCB-170, PCB-180, PCB-198, PCB-28, PCB-3, PCB-31 , PCB-40, PCB- 52, Hexachlorobenzene, o'p-DDE, o'p-DDT, p'p'-DDD, p'p-DDE, p'p-DDT, Phenanthrene, Anthracene, Fluoranthene, Pyrene, Benz(a)anthracene, Chrysene, Benzo(b)fluoranthene, Benzo(k)fluoranthene, Benzo(a)pyrene, lndeno(1 ,2,3-cd)pyrene.

40. The method according to any of the claims 20 to 39, wherein the first and/or second solvent is selected from the group of alkane, arene, alkylhalide, ketone, ether, alcohol, ester, nitrile,carboxylic acid, amine, nitro, amide, sulfoxide, thioketone, water, alkene, arylhalide, super critical fluid or a mixture of these.

41. The method according to any of the claims 20 to 40, wherein the first and/or second solvent is selected from the group of isooctane, toluene, dichlormethane, acetone, diethylether, methanol, ethylacetate, acetonitrile, glacial acetic acid, diethylamine, nitromethane, dimethylformamide, dimethylsulfoxide, carbon disulfide, limonene, chlorobenzene, super critical carbon dioxide or a mixture of these.

42. A method for the production of a device suitable of isolating, concentrating and/or determining at least one compound, the method comprising

• providing a supporting means,

• providing at least one retaining material comprising a polymeric material and optionally a non-polymeric material in the form of a solution and/or a dispersion, where the retaining material is capable of retaining at least one compound when the retaining material and/or compound is in substantially dry condition,

• placing the retaining material solution and/or retaining material dispersion on or within the supporting means,

• securing the retaining material on or within the supporting means, and hereby

• obtaining a device comprising a supporting means with a retaining material secured on or within the supporting means.

43. The method according to claim 42, wherein the retaining material is physically placed on or within the supporting means and/or secured to the supporting means by evaporative deposition of the retaining material solution and/or the retaining material dispersion, hereby the retaining material is present at the exact location where the evaporation is terminated.

44. The method according to claim 42 or 43, wherein the device further includes the features of any of claim 1 to 19.

45. Use of the device according to any of claims 1 to 19 for isolating, concentrating and/or identification at least one compound.

46. Use of the method according to any of claims 20 to 41 for isolating, concentrating and/or identification at least one compound.