ES2350200A1 - Equipment and method for extracting an extract from a sample, using, to that end, an extractant and extract preconcentration - Google Patents

Abstract

Equipment and method for the extraction of an extract sample using an extractant and precocentration of extracts. The present invention refers to equipment and methodology for the extraction of an extract sample using an extractant. Said equipment comprises at least one support, preferably an inert disk (1) with at least one compartment (2, 2'', 2'''') and a conduit (3); and centrifugation means (4) comprising an electric motor (11); where said centrifugation means (4) are such that they allow the variation of speed, acceleration and direction of rotation of the disk (1), or other conditions such as pressure, atmosphere and temperature, said disk (1) being integral with the centrifugation means (4) by means of a support (5) comprising a plurality of magnets (6) on its surface. In this way, by rotating the disk at a sufficient speed, the extractant mixed with the sample will be able to extract an extract from the sample. The invention also describes a method for carrying out said extraction, cleaning the extracts and automating the entire process.

Description

Equipment and method for extraction in a sample of an extract using an extractant and precocentration of extracts.

Object of the invention

The object of the present invention is a device and method for performing extractions in a sample using for this an extractant, by means of an automated equipment, consisting essentially of an extracting platform and an engine, which allows the application of a magnetic field, the variation of the speed, acceleration, direction of rotation as well as temperature, pressure and working atmosphere.

Background of the invention

Liquid-liquid extraction and solid-liquid extraction are techniques of Preparation of widely used samples for purification of substances, enrichment (pre-concentration) and matrix change They find applications in many fields and problems that range from analytics to preparations to Laboratory or industrial scale.

Solid-liquid extraction [Thurman, E.M., Mills, M.S. Solid-Phase extraction. Principies and practice. John Wiley, N.Y. 1998] is based on recovering selectively one or more substances, contained in a sample liquid or previously dissolved, using a solid consisting of silica gel, styrene-divinylbenzene or a material similar, chemically functionalized, so that they can be anchored on its surface different compounds. This allows you to choose the properties of the base material.

There are commercial media with different features and presentations, allowing to extract from very hydrophobic substances (octadecyl phase, C18) until everything opposite, polar substances (ion exchange phases), In addition to being able to incorporate other media such as those of molecular imprint and other separation mechanisms such as example, molecular exclusion or bioaffinity.

The methodologies in use for extraction solid-liquid arrange the solid support in a cartridge, syringe or membrane where the sample is forced to pass liquid Subsequently, the support is washed several times with a suitable liquid and finally the retained substances are eluted in the solid phase using the appropriate extractant. Sometimes, this extract is subsequently preconcentrated under vacuum, by solvent entrainment with gases (N2), broken-evaporation, etc. All these operations are can be done manually or with varying degrees of automation.

There are different firms that market the stands and accessories for handling, very positioned in the market.

In addition to the general methodology already mentioned, there are other proposals that use, for example, magnetic stirring bars (Stir bar solid phase extraction, SBSE) coated with a solid (polydimethylsiloxane, PDMS) that acts as an extractant. This application is very interesting to extract apolar substances in aqueous media, since the desorption of the analytes is carried out thermally, with the great advantage of not needing organic solvents [Beyer, A., Biziuk, M. Applications of sample preparation techniques in the analysis of pesticides and PCBs in food. Food Chemistry 108 (2008) 669-680.].

On the other hand, there are different commercial equipment for solid-liquid and liquid-solid extraction, such as those manufactured by DIONEX Corporation ( http://www1.dionex.com/en-us/ASE/lp65455.html ). Through this equipment, the extraction process can be automated, however they are expensive and use significant amounts of sample and solvents.

All these modes of operation present as main disadvantage the difficulty of automating at prices reduced by a simple and effective team that combines positive aspects of the protocols and means in use. Too require using significant volumes of organic solvents of high purity with a high economic impact, since in addition they are substances classified as problematic (toxic, flammable, etc.) so that its storage and disposal also increases its use.

Liquid-liquid extraction, It is based on the separation of one or several substances of interest, using an extractant liquid not miscible with the sample problem (Seader, J.D. and Henley, E.J. Separation Process Principies John Wiley and Sons. New York, 1999). Is this one well established and well known separation technique, applied as laboratory technique or industrial uses. There are different equipment for the automation of the technique, especially with analytical purposes The main limitation is the excessive consumption of solvents and laboratory equipment.

Finally the extraction liquid-solid is a technique similar to the solid-liquid, with the difference that in this In case the extractant is a liquid and the sample is a solid. A An example on an industrial scale is the extraction of seed oils oilseeds by hexane.

Description of the invention

In order to solve the problems above mentioned, the equipment and method for extraction is presented in a sample of an extract using an extractant object of the present invention. Throughout the present invention understand by sample a mixture of at least two substances, being able to be solid or liquid, always being present at least a liquid substance, from which it is desired to isolate and obtain one of these substances. The extract will be the substance obtained, which It will be a liquid substance. The extractant will be an element that will add to the sample, with the intention that by their physicochemical characteristics be able to separate The sample extract. Said equipment includes at least:

- a disc, extractor or extractor platform inert comprising, in turn, a plurality of compartments, comprising a sample compartment, a compartment of waste and an extract compartment, and ducts. Said disk It may be made of plastic or other metallic materials, ceramics, glass, composites, etc., resistant to different working conditions (for example samples that deteriorate polymer, or samples that become contaminated with the material it composes the body of the extractor), and

- centrifugation means comprising a explosion-proof electric motor, such that it allows the variation of speed, acceleration and direction of rotation of the disk plastic which is integral with the motor by means of a support which, in turn, comprises a plurality of magnets in its surface;

Where in one of the cavities or compartments of sample is a predetermined amount of extractant, and a small inert and paramagnetic metal piece that will act as mechanical stirrer Said extractant may consist of a support solid, same as those used in standard cartridges, or a Liquid not miscible with the problem. To this cavity or compartment Sample is sent, manually or through a dispenser automatic, a known volume of sample.

Then the disk is attached in solidarity on the motor shaft, so that the stirrers move by effect of the magnetic field created by the magnets located between the motor and the disk, stirring the sample / extractant mixture.

Once this operation is completed, the direction of rotation of the disc and the liquid is moved to the sample extract compartment. This stage can be repetitive, comprising several equal stages performed one after other. For example, in liquid-liquid extractions, the extract can be extracted only once or after separate sample and extractant, add extractant liquid again and get a second volume of extract. This process can be done. repeat as many times as you like until the compartment is filled collection of extracts. Finally, and if deemed necessary, it can partially or totally remove the solvent from the extract rotating the disc at a given speed and allowing the fluid evaporated out through the vent hole outside. This solvent removal operation of the extract, as the extractor inside a sealed chamber, can be carried out also under reduced pressure or vacuum, so that the Evaporation rate and reproducibility of this stage. How it will show, the vacuum is much more effective than the speed of turn, when evaporating solvent. In this way, the reduction of the volume of the extract, that is, its preconcentration

Additionally, the present invention is of application for cleaning or filtering the extracts obtained. To do this, the receptacle where the extract of each is recovered sample, the extract compartment, instead of being empty, may be partially filled with a substance that allows selectively clean the extract, such as sodium sulfate to dehydrate or molecular sieves that selectively remove alcohols, oxygen, etc. In this way, while separating the extract, this is mixed with the solid cleaning medium allowing its purification Since there are two non-miscible phases, the extract can Recover easily by suction of the liquid phase.

According to what has been described above, the team can work in a controlled atmosphere, being able to reduce or increase humidity, or in a reducing, oxidizing or inert environment, as well as with any other modification of the parameters of the variables that define the atmosphere of the procedure, without more than vary working conditions, injecting the gas of interest, for example argon, or eliminating the one that suits, for example oxygen.

Another way to operate the equipment is by temperature and pressure control above atmospheric. To do this, the pressure of the extraction equipment is raised by gas injection. The temperature is regulated by switching a resistor or a Peltier device, if requires a refrigerated medium. Both accessories are incorporated in the Extraction device housing. This work alternative It is especially interesting when the sample or extractant is Very volatile at atmospheric pressure.

On the other hand, the team can be provided with a head movable in height along the axis perpendicular to the surface of the disc, with cannulas that are inserted in the holes Sample inlet and ventilation of the chamber where it is collected each extract, so that samples can be dispensed in extraction chambers or sample compartment and collect the extracts in their corresponding receptacles or compartment of extract to then be transferred to containers or others equipment. Liquid handling is carried out by means of a pump piston connected to a multiport rotary valve, or equipment liquid handling assistant of the many that exist in the market.

Brief description of the figures

Then it goes on to describe very brief a series of drawings that help to better understand the invention and that expressly relate to an embodiment of said invention presented as a non-limiting example of is.

Figure 1. Shows a schematic view of a extraction equipment object of the present invention.

Figures 2. Shows a schematic view exploded equipment for extraction object of this invention, according to figure 1.

Figure 3. Present one of the different modes which can be used for sealing the extraction device. In this case the tightness is achieved through the interposition of a gasket of a polymer inert to the liquids handled in the Extraction and cleaning of extracts, and between the body of the extractor, where the cameras and ducts are engraved, and the cover of closed. This disc sealing device is part member of the equipment object of the present invention.

Figure 4. Shows a detailed view of the chambers and ducts of the disk, integral part of the equipment object of The present invention. This scheme can be altered at will to adapt the extraction equipment to different problems that require varying the amount of extractant, solid or liquid, and the sample volume, liquid or solid.

Figure 5. Shows the disk enclosed in a chamber equipped with a cover and two ducts for entry and exit of gases

Figure 6. Height adjustable head for dispensing or suction of sample or solvent in the chamber of Extraction and recovery of extracts, respectively.

Figure 7. Shows a graph in which represents the evaporation capacity of methanol as a function of speed of rotation of the extractor.

Figure 8. Shows a graph in which represents the evaporation capacity of methanol as a function of vacuum applied.

Figure 9. Shows the performance variation Extraction depending on the number of stages applied.

Preferred Embodiment of the Invention

As can be seen in the figures attached, the equipment for extraction in a sample of an extract using for this purpose an extractant, object of the present invention, includes at least:

- a support for extraction, preferably, but not only, an inert disk (1) comprising, in turn, a plurality of compartments (2, 2 ', 2' '), comprising a sample compartment (2), a waste compartment (2 ') and a extract compartment (2 ''), and ducts (3); Y

- centrifugation means (4) comprising, a in turn, an electric motor (11) and means to modify the working conditions, i.e. pressure, temperature and atmosphere of the sample,

wherein said centrifugation means (4) are such that allow the variation of speed, acceleration and direction of rotation of the disc (1), which is integral with the means of centrifugation (4) by means of a support (5) which, in turn, It comprises a plurality of magnets (6) on its surface.

The disc (1) is of an inert material with respect to the substance and sample in extraction, not ferromagnetic, preferably of plastic material.

Similarly, the team comprises at least one mechanical stirrer (7) such that at least one mechanical stirrer (7) can be introduced into each sample compartment (2) of the disk (1), wherein said agitator (7) consists of a metal part inert and paramagnetic, or the same piece covered with a inert material, such as plastic, glass, ceramics, etc.

The invention also comprises a device sample dispensing in the extraction chambers and of recovery of extracts in their corresponding receptacles or extract compartments (2 ''), shown in figure 6. The dispensing device consists of an axis (8) by which moves a head (9) with a number of cannulas (10), of material inert, preferably stainless steel, equal to that of receptacles or extract compartments (2 '') or extraction chambers and Extract recovery, connected by polymer tubes inert, for example Teflon, to a suction / delivery pump of fluids

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The method for extracting solid samples and liquids, second aspect of the present invention, comprises, at less, the following stages:

- a first stage where, in one of the sample cavities or compartments (2) of the disk (1) a mechanical stirrer (7) and a predetermined amount of an extractant. He extractant may be selected from:

-

solid extractant support;

-

liquid not miscible with the trouble;

- a second stage of insertion of a volume or known sample mass;

- a third stage of disc placement (1) in the centrifugation means (4), so that the stirrers (7) move by the effect of the magnetic field created by the magnets (6), permanent or electromagnets, located between the motor (11) and the disk (1), on the supports, stirring the mixture: extractant-sample;

- a fourth stage of reversal of the meaning of rotation of the disc (1) and the liquid is moved to the extract collection chamber.

The operations of the first, second or third stage can be done manually, using a glass pipette or automatically, or automatically using the handling equipment liquids described above.

The exposed methodology incorporates the purification of the extracts by cleaning with a solid, located in the chamber where they recover after their separation of the original sample.

Finally, the method contemplates the variation optional extraction conditions by modifying pressure and temperature or an additional stage at the end of the fourth stage, where said additional stage comprises partial or total elimination of the extract solvent by rotating the disk (1) to a large speed and allowing the evaporated fluid to exit through a ventilation hole spontaneously or by modification of working conditions, such as pressure, atmosphere and / or temperature.

In this way, the reduction of the volume of the extract, that is, its preconcentration, where in the Work scale used can handle between 6 and 12 samples per disk

This solvent removal operation of the extract, when the extractor is inside a chamber waterproof, see figures 1 and 5, can also be carried out under pressure reduced or empty, so that the evaporation rate is improved and the reproducibility of this stage.

As an example, the following is described extraction of an insecticide in a water sample with insecticide, being therefore, both the extractant and the sample both liquid For the insecticide extraction it will be used as hexane extractant, which is not miscible in water.

In the sample compartments (2) of the disc (1) the sample of water and insecticide, the hexane and mechanical stirrers (7). Once in the sample compartments (2) the mixture is present sample-extractant will proceed to spin the disc (1) in a first direction of rotation, levógiro, for example, at a certain speed, so that by the action of extractant, hexane in this case, and of the mechanical stirrers (7), the insecticide will be extracted from the water, and, increasing the speed and change of direction of rotation the supernatant hexane will pass to extract compartment (2``). In the sample compartment (2) in which the water remains with the residual insecticide, plus some another type of substance, hexane can be added again and made a second sample extraction according to the procedure described above. In this way, the total extraction of the Sample insecticide. Successive hexane extracts leave incorporating into the extract chamber (2 '') until the end of process. Additionally, the speed of rotation may be further increased or reduce the pressure in order to evaporate part of the hexane present in the extract and get an extract with a higher concentration of insecticide.

The procedure described is also of application if in the previous sample of water with insecticide, liquid sample, a solid is used as an extractant, as you can be an octadecyl phase or C18. In this case, the C18 will capture the insecticide when the sample compartment (2) is placed Sample and the C18. As in the previous case, the water will pass to a waste compartment (2 '). Again, the first one will be cleaned sample compartment (2) with distilled water, passing the residue also obtained to the waste compartment (2 '). With the purpose of separate the insecticide from C18, it is added in the compartment of sample (2) methanol and the disk (1) is rotated in the direction contrary to what has turned before. Methanol will capture the insecticide and the extract will be evacuated to the extract compartment (2``) from which it will be collected for later use, in this case your analysis.

The invention also applies to the extraction, for example, of hydrocarbons in sand. The sample will be in this solid case, the sand with the hydrocarbons absorbed into the same. As an extractant a liquid can be used, as per Hexane example. As in the previous cases, hexane will dissolve or will capture the product to be extracted, that is, hydrocarbons, which they will pass directly to the extract compartment (2``). This same operation may be carried out repeatedly to achieve the quantitative extraction of extracts or analytes.

Figures 7 and 8 show the ability to methanol evaporation as a function of the speed of rotation of the extractor and vacuum applied. As you can see, it is much more effective the vacuum that the speed of rotation, when evaporating solvent

Figure 9 shows the variation in performance Extraction depending on the number of stages applied. So when a nonpolar dye dissolved in water with a C18 support is removed, it is observed that the recovery by the support increases to as the extraction is more repetitive, manifesting a behavior similar to that shown by other extraction techniques comparable.

Claims (14)

1. Equipment for the extraction in a sample of an extract using for this purpose an extractant characterized in that it comprises at least: a) - an inert disk (1) comprising at least a compartment (2, 2 ', 2' '), said compartment comprising a sample compartment (2), a waste compartment (2 ') and a extract compartment (2 '') and a duct (3); Y b) - centrifugation means (4) comprising an electric motor (11); c) - said disk (1) being integral with the centrifugation means (4) by means of a support (5) that It comprises a plurality of magnets (6) on its surface.

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2. Equipment according to claim 1, characterized in that it additionally comprises at least: d) - a device for injection and / or gas removal, and / or e) - a resistor and / or device Peltier

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3. Equipment according to any of claims 1-2, characterized in that it additionally comprises at least: f) - a head movable in height according to the axis perpendicular to the surface of the disc (1), with cannulas that are inserted into the sample inlet and ventilation holes of the compartment (2), and / or g) - a piston pump connected to a valve Multiport rotary or auxiliary equipment.

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4. Equipment according to any of claims 1-3, characterized in that the disc (1) is made of a non-ferromagnetic material. 5. Equipment according to any of claims 1-3, characterized in that the disc (1) is made of inert material. 6. Equipment according to any one of claims 1-5, characterized in that it comprises at least one mechanical stirrer (7) in such a way that it can be inserted into at least one sample compartment (2) of the disc (1). 7. Equipment according to claim 6, characterized in that said mechanical stirrer (7) is an inert and paramagnetic metal part. 8. Equipment according to claim 6, characterized in that said mechanical stirrer (7) is an inert and paramagnetic non-metallic part. 9. Method for the extraction in a sample of an extract using for this purpose an extractant characterized in that it comprises at least the following steps: a) - a first stage where, in a sample compartment (2) of a disk (1) a stirrer is placed mechanical (7) and a preset amount of extractant b) - a second stage of insertion of a known volume of liquid sample in the sample compartment (2) of the disc (1), forming a mixture extractant-sample; c) - a third stage of disc placement (1) in centrifugation means (4) and disk centrifugation at a predetermined speed and in a direction of rotation, so that the stirrers (7) move due to the magnetic field created by magnets (6) located between a motor (11) and the disk (1), stirring the extractant-sample mixture; d) - a fourth stage of sense inversion of rotation of the disc (1), moving the extract to a chamber of pick up

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10. Method according to claim 9 characterized in that after the fourth stage, it comprises at least the following stage: e) - a fifth stage in which the said chamber Collection is filled with a substance or molecular sieves.

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11. Method according to claim 9 and 10 characterized in that after the fourth stage, it comprises at least the following stage: e) - a fifth stage consisting of repeating the cited fourth stage as many times as you want to fill the quoted extract collection chamber.

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12. Method according to any of claims 9-11, characterized in that after the fourth stage, it comprises at least the following stage: e) - a fifth stage consisting of modifying the aforementioned speed of rotation of the disc (1) until reaching the partial or total evaporation rate of a solvent from the liquid sample, allowing evaporated fluid to flow out ventilation hole.

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13. Method according to any of claims 9-12 characterized in that the extractant is a solid support. 14. Method according to any of claims 9-12 characterized in that the extractant is a liquid not miscible with the sample.