WO1997029846A1

WO1997029846A1 - Pipetting devices preloaded with standardized control sample materials

Info

Publication number: WO1997029846A1
Application number: PCT/US1997/001712
Authority: WO
Inventors: Stephen F. Mauro; Robert A. Reynolds
Original assignee: Aalto Scientific, Ltd.
Priority date: 1996-02-13
Filing date: 1997-02-11
Publication date: 1997-08-21
Also published as: AU2255897A

Abstract

Devices and apparatus are disclosed for rapid, consistent, precise and accurate formation of standard solutions for use as reference samples without error, excessive costs, waste and degradation problems. Test reactants, normally solutes, are preloaded in measured amounts into pipette tips or instrument tubing. The devices draw in a measured quantity of liquid, normally solvent, through the tip or tubing, which quickly dissolves or disperses the solute, forming a consistent and accurate solution for an individual test. Since only the amount of solute and solvent which is needed for each individual test is used, there is no preparation of excess solution. Since the invention involves the production of pipette tips preloaded with stable solute, it can be used in many different settings, including emergency rooms and vehicles. Also disclosed is a container for retaining a readily available supply of solvent adjacent to detached pipette tips containing preloaded solute samples, such that when the technician connects the pipette tip to the pipette, the required quantity of solvent can also be obtained and the desired solution sample produced in a single operation.

Description

PIPETTJNG DEVICES PRELOADED WITH STANDARDIZED CONTROL SAMPLE MATERIALS

BACKGROUND OF THE INVENTION Field of the Invention:

The invention herein relates to pipettes and pipetting equipment and instruments. More particularly, it relates to such devices which are used to collect and dispense reference materials for use as primary/secondary standards, calibrators or quality controls in medical, biological and chemical tests.

Description of the Prior Art:

In many medical, chemical and biological laboratory and research procedures, it is necessary to calibrate or standardize analytical instruments, reagents and test procedures and to utilize quality control materials of known properties in order to obtain valid results from analytical or comparative testing of patient samples or the like. For instance, in emergency treatment, the properties of fluid (e.g., blood) samples drawn from the patient are compared against standard reference samples to identify the extent to which the patient's fluids exhibit properties differing from normal fluid properties, so that the physician can diagnose the disease or dysfunction from which the patient is suffering.

It will of course be evident that accurate standard reference samples are absolutely necessary if valid comparisons are to be made with patient samples and accurate diagnoses of patient conditions are to be obtained from the resulting data. In conventional practice, reference materials are made up in quantity by dissolving a sample of the reference analyte in a volume of the desired solvent liquid. Analytes are usually provided in solid dehydrated or preferably lyophilized form, since in such forms the analytes, most of which are organic and biological materials, have stable extended shelf lives. The laboratory conventionally mixes a sufficient quantity of solution to enable drawings of reference samples for as long a period as the solution remains effective (which may be from several hours to several weeks). This conventional practice, however, has several drawbacks and allows for the introduction of several different types of error. For instance, errors can arise during measuring of the quantity of solid analyte and/or the liquid solvent, during withdrawal of individual sample quantities from the formulated solution, and by partial loss of sample during transport of the reference sample from the solution container to the place at which the experiment is to be run. Such errors may be random (such as when a laboratory technician misreads the measured weight of the solid analyte or a portion of sample leaks from the test instrument) or systematic (such as when the scale used to weigh the solid analyte is improperly calibrated). Thus, unless the technician works with extreme skill and carefully checks all measurements and equipment frequently, significant errors in standard reference samples can be anticipated. In actual daily practice, the time demands on laboratory technicians are usually such that there is little time for such thoroughness. Errors therefore consistently creep into reference samples and thus are incorporated into reference data.

In addition, conventional practice for preparation of reference materials is wasteful and expensive. Since it is has not been practical to make up an individual solution for each sample, it is common (as noted) for a large quantity of reference solution to be produced on some daily, weekly or monthly basis, from which the individual reference samples are subsequently drawn. Since one can rarely anticipate accurately how many reference samples will be needed in the course of a day, week, etc., an excess quantity of solution must be initially prepared. This results at the end of the service period in a significant quantity of unused reference solution being discarded, since it is no longer effective for tests. Since many of the analytes are quite expensive, this results in a large economic loss. In addition, discard and safe disposal of reference solutions often require special handling, also resulting in significant costs.

Further, while analytes may have extended stability in solid or lyophilized form, stability begins to decrease once the analyte is dissolved in the solvent liquid. Thus, over time the master solution properties change, thus often also changing the reference data of the samples. Therefore the laboratory technicians must apply correction factors to the standard samples, depending on when the samples have been drawn from the master solution. Such corrections can introduce additional errors, since the technician may incorrectly calculate or apply the correction, or the correction value itself may be uncertain, since the exact degree of degradation of the master solution normally can only be roughly estimated. SUMMARY OF THE INVENTION

The devices and apparatus of this invention avoid the potentials for error, excessive costs, waste and degradation problems of the prior art, and permit the rapid, consistent, precise and accurate formation of standard solutions for use as reference samples. One of two reactants which will form the desired test solution (preferably the solute/analyte, but also alternatively the solvent) is incorporated (preloaded) in precisely measured amounts into a pipette tip, instrument tubing or similar conduit, in which form it has long term stability, similar or equivalent to that of lyophilized solutes, and can be subsequently readily and quickly combined with the other reactant to form the desired solution. Use of such preloaded pipette tips and calibrated instruments permits drawing of accurate predetermined quantities of the reactant liquids into contact with the reactant solids, with the rapid reaction of the two materials and resulting dissolution of the solute, thus forming a consistent and accurate solution for each individual test. The system is useable for formation of many different standardized reference solutions and with a variety of different analysis instruments. It substantially eliminates the opportunity for operator error. It also operates such that only the amount of solute and solvent which is needed for each individual test is used, so that there is no preparation of excess solution, eliminated solution waste and disposal problems. Since the invention involves pipette tips preloaded with stable reactant, it can be used in many different settings, including emergency rooms and vehicles.

In one broad embodiment, the invention is a pipetting device for collecting and dispensing a liquid sample of known properties, which comprises a walled hollow liquid reservoir with an opening in a wall thereof providing liquid access to the reservoir; a elongated tubular liquid conduit attached to the opening and providing liquid communication between the reservoir and an exterior of the device; liquid transfer means cooperating with the reservoir for alternately drawing a defined volume of reagent liquid into the reservoir from the exterior through the conduit and dispensing a corresponding volume of the liquid sample to the exterior from the reservoir through the conduit; and reactant containment means within the conduit for containing a defined quantity of reactant therein, if the reactant is a solute, the solute being rapidly and fully soluble or dispersible in the reagent liquid containing a respective solvent, and if the reactant is a solvent, the solvent rapidly and fully dissolving or dispersing a respective solute contained in the reagent liquid, and the reactant containment means further permitting flow of the volume of reagent liquid therethrough for contact between the solute and the solvent, the solvent thereby dissolving or dispersing the solute therein to form the liquid sample; whereby subsequent dispensing of the formed liquid sample yields a reference material of known properties.

The conduit may be a pipette tip, flexible tube or similar confining conduit. For convenience it will be exemplified herein as a pipette tip, which is anticipated to be the most common form. The invention is capable of operating effective with either the solute (analyte) or the solvent being the material preloaded into the pipette tip, with the other reagent being present in the liquid drawn into the tip during use. For the most part, however, it is anticipated that the material preloaded into the tip will be the solute or analyte, with the solvent being present as or as part of the drawn liquid; therefore again for convenience the system will be exemplified herein with the solute in the tip and the solvent in the liquid. As intended herein, the reservoir may be part of a pipetting or similar instrument or it may be a pipette itself, and is formed to contain the desired predetermined volume of drawn liquid, with operation of the device precisely and accurately drawing in that specific quantity of solvent liquid desired for dissolution or dispersion of the solute to form the sample.

The invention also includes means for retaining a readily available supply of reagent liquid adjacent to detached conduits containing preloaded solid reactant, such that when the technician connects the pipette tip to the pipette, the required quantity of liquid can also obtained and the desired solution sample produced in a single operation.

Therefore, in another broad embodiment, the invention involves pipetting apparatus for collecting and dispensing a standard liquid sample of a control material, which comprises a walled hollow liquid reservoir with an opening in a wall thereof providing liquid access to the reservoir; a elongated tubular liquid conduit detachably attached to the opening and providing liquid communication between the reservoir and an exterior of the device; liquid transfer means cooperating with the reservoir for alternately drawing a defined volume of reagent liquid into the reservoir from the exterior through the conduit and dispensing a corresponding volume of the liquid sample to the exterior from the reservoir through the conduit; and reactant containment means within the conduit for containing a defined quantity of reactant therein, the reactant being a solute or solvent with a respective solvent or solute contained in the reagent liquid, the solute being rapidly and fully soluble or dispersible in the solvent, and the reactant containment means further permitting flow of the volume of reagent liquid therethrough in contact with the solute, the flow of the reagent liquid thereby contacting the solute and solvent and dissolution or dispersion of the solute in the solvent to form the liquid sample; whereby subsequent dispensing of the formed liquid sample yields a reference material of known properties. The detached conduits will preferably be pipette tips. Also present will be a container for retaining the detached pipette tips prior to being attached to a pipette or instrument reservoir. The container includes a basin for containing a body of the liquid (usually the solvent component of the solution) and a retainer, such as a rack, for retaining the detached pipette tips disposed above surface level of the body of liquid when the liquid is contained in the basin, the pipette tips also being retained in alignment for attachment to the reservoir, so that the motion of attaching a pipette tip to a pipette or instrument can also be used to immerse the distal end of the tip in the body in the liquid and draw the liquid into the pipette or instrument.

BRIEF DESCRIPTION OF THE DRAWINGS Figures 1 -5 are elevation views, partially cut away, of pipette tips, illustrating various embodiments of incorporation of preloaded materials within the pipette tips according to this invention. Figure 6 is a pictorial view of a pipetting machine with a flexible tube connecting the machine to the pipette tip, with an enlarged view of a portion of the tube illustrating the incorporation of preloaded materials within the tube.

Figure 7 is a diagrammatic perspective view illustrating apparatus of the invention in which representative pipette tips containing solute are retained in a package which also contains a quantity of solvent liquid, such that upon attachment of a preloaded pipette tip to a pipette or instrument, the required quantity of solvent liquid can also be drawn into the tip by a single operation. DET AILED DESCRIPTION AND PREFERRED EMBODIMENTS

The devices and apparatus of the present invention will be best understood by reference to the drawings. Figures 1 -5 illustrate typical pipette tips which are of the type normally used with conventional pipetting systems for single use applications. In a typical operation, the technician manipulates the pipette itself (not shown) which has a hollow tubular appendage 2 (illustrated only in Figure 1 ) which is inserted into the top end 4 of pipette tip 6 and secured therein, usually by a friction fit. Pipette tips have commonly been packaged in open racks so that the technician can easily secure the pipette to a pipette tip and withdraw the tip from the rack for use. Following use in prior art systems, the pipette tip may then be discarded or cleaned and reused, depending on the protocols of the system. It will of course be understood that in the prior art, pipette tips have always been empty hollow tips. In the present invention the same techniques for racking pipette tips and joining them to pipettes will be used. However, a critical feature of this invention is that, rather than the tips being empty, within the barrel 8 of the tip 6 there is disposed a preloaded quantity of reactant material 10 (exemplified hereafter as solute) which is secured in place for subsequent contact with the liquid 26 (exemplified hereafter as solvent).

In Figure 1 , a quantity of solute 10 in solid form is illustrated as secured in place by a porous distal barrier 1 2 and a porous proximal barrier 14 ("distal" and "proximal" being with relation to the pipette/reservoir). The particular solid form of the solute 10 is not specified in Figure 1 ; rather, the drawing is intended to illustrate generally a solid solute. This particular barrier configuration, however, is preferably used when the solute is in the form of particulated or granular material of relatively small particle size. The diameters of the pores of the porous barriers 1 2 and 1 will be smaller than the particle size of the particulated or granular solute material, such that the solute particles cannot escape from the containment chamber formed by cooperation of the barriers 12 and 14 and the inner surface of the barrel 8.

Figures 2, 3 and 4 illustrate other convenient embodiments by which the solute may be contained within the barrel 8 of the pipette tip 6. In

Figure 2, there are a plurality of small inert balls 1 6. If the balls are solid, they may have a coating of the solute 10 on them. Alternatively, if they are porous, solute 10 may be coated across the outer surface and incorporated within the pores of the balls 16. The "balls" need not actually be spherical; they may be of any convenient physical form. For instance, they may be of standard column packing shapes or other shapes which are convenient for receiving the coating of the solute 1 0 and being loaded into the pipette tip 6. The balls 1 6 are retained in place by proximal barrier 14 and distal barrier 1 2. In an alternative embodiment also illustrated by Figure 2, the solute 1 0 need not be coated on each ball 1 6. Rather some of the balls 1 6 may be made of an inert non-soluble material and other balls (designated 1 6') may be made in whole or in part from the solute itself, such that the solute 10 in ball 1 6' form is mixed in with equivalent but inert balls 1 6.

In Figure 3, the embodiment shown has the solute in the form of a solid annular plug 1 8 fitted tightly within the barrel 8 of the pipette tip 6. A hole 20 is left through the annular plug 1 8 to facilitate drawing in the solvent 26 to the pipette. In this embodiment, only the distal barrier 1 2 is required, although a proximal barrier 14 may also be used if desired.

In the embodiment shown in Figure 4, the solute 10 is in the form of a porous solid body 22 (not particulated) and only distal barrier 1 2 is usually needed, although again both barriers may be present if desired.

Figure 5 illustrates another embodiment of the invention, similar to that previously illustrated in Figure 4. However, Figure 5 illustrates that the solute 10, whether granulated or as a massive solid, can be secured at any position along the length of barrel 8 of pipette tip 6. It is preferred, however, that the solute 10 be positioned somewhere centrally of the barrel 8, as generally illustrated in Figures 1 -4, rather than being near the distal end 24 or the upper end 4 of the pipette tip 6. If the disposition of the solute 1 0 is too close to the distal end 24, there is some potential for solute material to be lost during the filling of the pipette with the solvent, while if it is near or within the upper or proximal end 4 there is a potential for interference with the attachment or detachment of the pipette tube 2. Proximal barrier 1 4 is normally hydrophilic, but in some cases

(discussed below) it may initially be at least slightly hydrophobic. Similarly, distal barrier 12 will be either initially hydrophobic (designated as 1 2 in the Figures) or initially hydrophilic (designated as 1 2' in the Figures). Whether a barrier 12 or 14 is initially hydrophobic or hydrophilic will normally depend on the manner in which the solute 10 is initially incorporated into the barrel 8 of the pipette tip 6 and the shelf life conditions of the preloaded pipette tips. For instance, if the solid form of the solute 10 is created outside the pipette tip, as would commonly be the case in the embodiment of Figure 1 (where a solid body of solute would be formed and then pulverized to form solid particles or granules), the embodiment of Figure 2 (where the solute- coated or -impregnated balls 1 6 or the solute balls 1 6' are formed outside the pipette tip) or the embodiment of Figure 3 (where the annular plug 1 8 is formed outside the pipette tip), both barriers may be hydrophillic. However, if it is possible that the preloaded pipette tips may be stored in a humid environment, it may be desirable to have the barriers be at least slightly hydrophobic, to prevent absorption of moisture through the barriers and into contact with the preloaded solid solute. This may be accomplished, if the barrier material itself is hydrophilic, by placing a thin hydrophobic coating over the outer surface (i.e., the surface which faces away from the solute body 10) of each barrier. Conversely, the barriers may be made of material which is initially hydrophobic.

Where the solid solute body 10 is to be formed in situ by deposition from or drying of an aqueous solution or slurry, as exemplified by Figure 4, it will be necessary for the distal barrier 1 2' to be initially hydrophobic, so that the liquid can be poured into the barrel 8 and will be blocked from draining out by the hydrophobic barrier 12' . Initial hydrophobicity may be imparted to the barrier 1 2' either by coating the inner surface (i.e., the surface which will face the solute body 10) with a thin hydrophobic material, or the barrier 1 2' itself may be made of initially hydrophobic material. The barrier 12' thus retains the solution or slurry in place while the water carrier evaporates, leaving behind the deposited solute 10 as porous body 22. Following the drying and solidification of the porous body 10, a proximal barrier 14 may optionally be emplaced. That proximal barrier may be either hydrophilic or hydrophobic, as discussed above.

Since the solvent 26 will normally be water or an aqueous body fluid, it will be necessary to incorporate into the solvent an additive which will convert an initially hydrophobic barrier to a hydrophilic barrier. (The additive itself of course must not be detrimental to the solute or affect the test results.) If the hydrophobicity was provided by a coating on a barrier, the hydrophobic coating must be rapidly dissolved by the additive. If the barrier itself was initially hydrophobic, the material from which it is made must be rapidly made hydrophilic by the additive. For the purposes of this invention, "hydrophilic" means that the barriers (filters) will wet simultaneously with water, which has a surface tension of approximately 72 dynes/cm² at normal ambient room conditions. "Hydrophobic" means that the barriers have sufficient surface tension of their own that they will not spontaneously wet with water, unless that surface tension is reduced. For instance, a PTFE hydrophobic barrier would require reduction of surface tension to about 50 dynes/cm² to be wetted by pure water. One may use a wetting agent such as detergent or organic solvent with a surface tension of less than 32 dynes/cm² in the solvent to wet the barrier and make it hydrophilic. Various materials which can be converted from hydrophobic to hydrophilic in this or a like manner are well known and can be obtained commercially. The particular materials chosen for the additive and barrier will be determined by the nature of the solvent 26 and the solute 10, since the additive and the barrier material must both be inert to the solute and solvent, so that the nature of the resulting reference solution is not adversely affected. For instance, if the barrier material is too strongly hydrophobic, while it may be converted to pass some solvent water it may still bind too much solute protein and therefore adversely affect test results. Useful barrier materials include, but are not limited to, cellulose acetate, modified polyvinylidene fluoride, and nylon (all hydrophilic) and polytetraf luoro- ethylene (PTFE), polyvinylidene fluoride, and innobilou XXX (all hydrophobic).

Figures 1 -5 illustrate the incorporation of the solid solute into pipette tips. Such preloaded tips represent an important end use of the present invention, and will be purchased by many laboratory, hospital, emergency care and other facilities for use in a wide variety of commonly conducted tests in which a pipetted reference standard is required. It will, however, also be recognized that the invention may be used in other test instruments and automated pipetting systems for reference samples where those instruments or systems operate in a manner akin to a typical pipette, by drawing in a predetermined quantity of solvent and forming a standard solution from the solvent and the specific quantity of preloaded solute. Such a system is illustrated in Figure 6. An instrument 28 is shown generically. This instrument may be any one of many different types which form a reference solution sample and a test solution sample and separate, compare specific predetermined properties of the two samples and then display a differential value reading for a desired property or for some other indication to a technician, such as on a display screen 30. In the instrument shown schematically in Figure 6, the reference sample is formed by drawing in solvent 26 through tubing 32. Tubing 32 terminates in a tip 34 which is inserted into a body of solvent 26 which is drawn upward through the tubing by a pump (not shown) within the instrument. As the solvent is drawn up the tubing 32, it encounters a body of solvent 1 0 retained in place by barriers 1 2 and 14, in a manner similar to that shown in Figures 1 and 2. The solvent 26 passes through the barriers 12 and 14, simultaneously dissolving the solute 10, such that when the resulting solution reaches the instrument through the remaining portion of tubing 32, it has formed a measured predetermined reference solution sample, as with the pipette systems. Since the tubing 32 is flexible, it will be preferred that the solute 10 be in the form of particles, granules, solid balls or coated balls, in forms equivalent to those shown in Figures 1 and 2, rather than being in the form of a rigid solid body, as in Figures 3 and 4.

In operation of the embodiments shown in Figures 1 -5, the operator will normally place the pipette appendage 2 at the proximal end 4 of the preloaded pipette tip and couple the two together, normally simply by pushing the appendage 2 into the top 4 of the tip 6, as in the prior art procedures. It is convenient for the pipette tips for this type of operation to simply be packaged in conventional racks as are the prior art non-preloaded tips. The technician thus can use the same procedure that he or she is familiar with to secure the preloaded tip of this invention to the pipette. The pipette is then moved to a separate container of solvent 26 and the solvent is drawn in to the pipette by a conventional pipette mechanism, which is calibrated to draw in a precise predetermined quantity of solvent. As it is drawn in through the tip 6, the solvent 26 passes over and through the mass of the solute 10 and rapidly dissolves it completely. To facilitate complete dissolution, it will usually be desirable to have the solvent 26 completely fill not only the pipette chamber, but also enough of the pipette tip to completely surround the remaining initially undissolved portion of the solute, so that the dissolution can continue until complete. The solute will be sufficiently rapidly soluble that complete dissolution will occur in no more than about 30 seconds, and preferably will occur within about 5-1 5 seconds. The technician waits this length of time and then transfers the now formed solution of the solute and solvent to a receptacle (such as test tube, petri dish, test instrument chamber or other similar conventional receptacle) into which is deposited the entire solution to form the control or reference sample. The emptied pipette tip will then commonly be discarded. Alternatively, however, it may in some cases be desirable for emptied tips to be collected for recycle by sterilization and refiling.

It will be evident from this description that the formation of precise and accurate standard reference samples is assured by the present invention. The tip is preloaded with a predetermined quantity of solute, the pipette is chosen to draw in exactly the quantity of solvent desired, and the solute dissolves rapidly and completely when contacted with the solvent. Consequently, the resulting solution is of an exactly known combination of solvent and solute such that the properties of that solution are a precise and consistently repeatable standard. The potential for technician error is essentially eliminated, since the technician does not measure either the amount of solute or solvent used. While conceivably a technician might not allow sufficient time for complete dissolution of the solute to take place prior to dispensing the solution from the pipette into the target receptacle, the dissolution is normally sufficiently rapid that it will be completed during the time it takes the technician to move the pipette from the solvent container to the target receptacle. Indeed, this is desirable wherever possible, since it minimizes the time required for producing each sample, and therefore maximizes the number of samples that a technician can accurately produce within a given time period. Of course, if an automated system such as one using instrument 28 is being run, the chance for operator error by premature dispensing of the solution before complete dissolution of the solvent is eliminated.

Common solute materials which will be used with the preloaded pipette tips or tubing of the present invention include, but are not limited to, ( 1 ) materials obtained from human or animal body fluids such as blood, serum, plasma, urine, cerebrospinal fluid, pleural fluid, ascitic fluid, tears, sweat, saliva and amniotic fluid; (2) processed or purified human or animal proteins, peptides, lipids or carbohydrates in native, processed or synthetic human or animal body fluids; or (3) dried synthetic or semisynthetic human or animal body fluids, buffers or other stabilizing media containing various amounts of actual body fluids as in ( 1 ) above or purified or processed materials as in (2) above, or combinations thereof.

The aqueous solvent may be water, an aqueous buffer, native or processed human or animal body fluid or other solutions containing, where applicable, appropriate concentrations of wetting agents. The wetting agents may be non-ionic, anionic or cationic, as appropriate to the particular solutions. Such wetting agents are well known and readily available commercially. Typical nonionic detergents include polyoxyethylene ethers (such as Triton™ X- 100, X- 1 14 or X-405) and polyoxyethylene sorbitans (such as Tween™ 20 or 80); typical cationic detergents include benzethonium chloride, cetylpyrindium XXX chloride and benzalkonium chloride; and typical anionic detergents include alginic acid and "Aerosol™ 22" . The aqueous solvent may also include dilute organic solvents in combination with the water, buffer or native or processed body fluid, with or without the presence of a wetting agent. Such organic solvents may include, but are not limited to, methanol, ethanol, glycerol, ethylene glycol and dimethyl sulfoxide (DMSO).

Figure 7 illustrates a further refinement of this system in which the preloaded pipette tip and the solvent can be obtained by the technician in a single operation and virtually a single motion. A container 36 has a rack 38 mounted near its top. In the rack 38 are mounted a plurality of pipette tips 6. (In Figure 7, two pipette tips 6, one of which is shown partially cut away, are illustrated as representative.) It will be understood that initially all openings 40 of the rack 38 may, and normally will, also contain preloaded pipette tips. Preferably these will all have the same solute loading and be of the same size, in order to further eliminate potential errors, but it is also possible to have a container with a variety of different pipette tip sizes, solutes and solute loadings, as long as they are individually clearly marked by labeling or color coding such that the technician can rapidly determine the correct preloaded tip to be used in a given test.

The container 36 will be significantly deeper than the prior art pipette tip rack containers, such that the distal end 24 of a pipette tip 6 is positioned only part way down into the depth of the container 36. This leaves a volume (depth indicated at 42) which is used to contain a quantity of the solvent 26. The solvent 26 may be loaded into the container 32 prior to closing and shipping, but more preferably the volume to house the solvent will be left empty during shipping. Thereafter, upon opening the package and readying it for use, the technician will pour a desired quantity of solvent 26 into the bottom portion of the container 36, normally to the depth 42, to fill the volume. Conveniently, one of the openings 40 in the grid 38 may be left vacant to facilitate the technician's transfer of the solvent 26 from a supply source to the interior of the container 36.

The rack or grid 38 will be made of a flexible material such that after the technician brings the pipette and its protrusion 2 into contact with and joins the upper portion 4 of the pipette tip 6, the technician can continue to push the assembled device downward, flexing the rack 38, until the distal end 24 of the pipette tip 6 is submerged in the body of solvent liquid 26. The predetermined quantity of solvent 26 can then be readily drawn into the pipette via the pipette tip and through the body of solute 10. Once the quantity of solvent liquid has been drawn into the pipette, the technician can merely lift the entire assembly (with the solute and solvent interacting) directly out of the rack 38 and transport it to the target receptacle. The rack 38 will also at that time resile to its previous position to keep the other remaining pipette tips out of the body of solvent 26 until each of them is to be submerged. The grid 38 will be made of a material (such as a plastic material) which has some degree of flexibility but is still sufficiently rigid to support the pipette tip 6 while the pipette appendage 2 is being pushed into the upper portion 4, and also to resile immediately upon withdrawal of the pipette tip 6 to its previous position supporting the remaining pipette tips.

As will be described in greater detail below, the devices and apparatus of the present invention may be used in a wide variety of end uses, including but not limited to analyses of bodily fluids such as blood, semen, urine, spinal fluid, saliva and sweat. It may also be used in any type of chemical or biological analysis where a test solution must be compared with a standard solution. The system will thus find use in chemical and biological laboratories, medical facilities, including emergency rooms and similar locations. It is particularly useful in emergency medical situations and locations, such as being in the inventory of materials available on emergency response vehicles for people such as paramedics. Since both the amount of solvent and of solute are predetermined, an emergency medical technician can simply use the current invention to withdraw a sample of bodily fluid (such as blood) from the patient into the pipette (usually by having a hypodermic needle tip at the end of the pipette tip) and then dispense the resulting solution into a test device within the emergency vehicle, such that test results can be available for the emergency room physician by the time the patient is delivered to the hospital. This ability has not been available before now, since emergency medical technicians have not had time to manufacture accurate reference solutions while attending to the patient or transporting the patient to the hospital, nor have emergency vehicles such as ambulances been equipped for such manufacture. However, with the present invention, by having all of the components immediately available and simply drawing the fluid through the preloaded sample device, whether a hypodermic or a pipette tip, the technician can quickly obtain valuable data about the patient's condition for the subsequent attending physician.

Because of the rapid dissolution of the solvent, the system is ideal for other applications where rapid results are needed, such as in running tests in an emergency room to make a rapid diagnosis of a received patient's condition, or where a large number of identical samples need to be run in a fixed period of time. Because this system can be repeated quickly and accurately, a laboratory technician can increase his or her productivity significantly by being able to make numerous consistent repeat samples in the time previously required for production of only a single sample. Further, because none of the samples formed by this invention have time before use for the solvent/solute solution to deteriorate significantly, all of the samples will be of equivalent accuracy and no time consuming and potentially inaccurate time calibrations or corrections need to be made. It will also be seen that the solute 10 need not be a single material, but in fact can be a plurality of different materials, all of which are rapidly soluble in the same solvent 26, but which can be used for reading of different properties or conditions of a patient. Of course, the individual solutes 10 must not interact with each other in a manner which would adversely affect the test readings. It is also possible to have different materials within the solute 10 which are themselves interactive but which do not react until they are both immersed in the solvent 26. This also allows for great stability and long shelf life, since the solute will have the shelf life of lyophilized materials, and solution or dispersion resulting from the combination of the preloaded solute and the drawn solvent will not deteriorate significantly in the short time from its formation to its use. As indicated above, the preloaded pipette tips, instrument tubing, and the like products will find use in many test and analysis procedures. These include, but are not limited to, blood chemistries tests such as for sodium, potassium, glucose and urea creatinine XXX; enzyme chemistries such as creatine kinase, lactate dehydrogenase, serum aspartate aminotransferase, alanine aminotransferase, and alkaline phosphate; cardiac emergency room chemistries such as creatine kinase MS, troponin T&l and myoglobin; serum protein electrophoresis and other electrophoretic tests to serve as position markers for the various protein or other analyte bands for proper identification; standards and control materials for all types of immunological tests, including for arthritis, lupus erythematosis, scleroderma, hepatitis and HIV; diabetes testing for glycated hemoglobin and other abnormal hemoglobins such as fetal and hemoglobin S; amniotic fluid testing for fetal lung maturity and other abnormalities of the fetus; urine testing for various pathologies as well as drugs of abuse and toxic chemicals; and tests for multiple sclerosis and other neurological pathologies using spinal fluid in conjunction with serum.

It will thus be evident, as noted, that the invention will find use in a wide variety of medical, research and other facilities, such as hospital labs, emergency rooms, surgery facilities, autopsy labs, medical examiners' labs, DNA/RNA analysis labs, military field hospitals, emergency vehicles, point-of- care treatment facilities, chemistry labs, water testing labs, veterinary offices and labs, physicians' offices, intensive care units, urgent care centers, organ, tissue, fluid and molecular pathology labs, polymerase chain reaction procedure labs, shipboard hospitals and labs, toxicology labs, patient beside testing, environmental labs and agricultural labs.

It will also be evident that there are numerous embodiments of this invention which, while not expressly set forth above, are clearly within the scope and spirit of the invention. The above disclosure is therefore intended to be exemplary only, and the actual scope of the invention is to be limited solely by the appended claims.

WE CLAIM:

Claims

1 . A pipetting device for collecting and dispensing a liquid sample of known properties, which comprises: a walled hollow liquid reservoir with an opening in a wall thereof providing liquid access to said reservoir; a elongated tubular liquid conduit attached to said opening and providing liquid communication between said reservoir and an exterior of said device; liquid transfer means cooperating with said reservoir for alternately drawing a defined volume of reagent liquid into said reservoir from said exterior through said conduit and dispensing a corresponding volume of said liquid sample to said exterior from said reservoir through said conduit; and reactant containment means within said conduit for containing a defined quantity of reactant therein, if said reactant is a solute, said solute being rapidly and fully soluble or dispersible in said reagent liquid containing a respective solvent, and if said reactant is a solvent, said solvent rapidly and fully dissolving or dispersing a respective solute contained in said reagent liquid, and said reactant containment means further permitting flow of said volume of reagent liquid therethrough for contact between said solute and said solvent, said solvent thereby dissolving or dispersing said solute therein to form said liquid sample; whereby subsequent dispensing of said formed liquid sample yields a reference material of known properties.

2. A device as in Claim 1 wherein said conduit comprises a pipette tip.

3. A device as in Claim 1 wherein said conduit comprises a flexible tube.

4. A device as in Claim 1 wherein said reservoir is formed to contain a predetermined volume of liquid, and said defined quantity of reagent liquid comprises said volume.

5. A device as in Claim 1 wherein said reactant containment means comprises a pair of barriers disposed across and secured within said conduit and spaced apart along the axis of said conduit, said barriers being permeable to said reagent liquid and defining a chamber therebetween wherein said reactant is contained.

6. A device as in Claim 5 wherein one of said barriers is initially hydrophobic and the other is hydrophilic.

7. A device as in Claim 6 wherein said barrier which is distal to said reservoir is initially hydrophobic and said barrier which is proximal to said reservoir is hydrophilic.

8. A device as in Claim 6 wherein said initially hydrophobic barrier comprises material which during use of said device becomes substantially hydrophilic.

9. A device as in Claim 8 further comprising said reagent liquid containing a component therein to render said initially hydrophobic barrier hydrophilic.

10. A device as in Claim 5 wherein both of said barriers are initially hydrophobic.

1 1 . A device as in Claim 10 wherein both of said initially hydrophobic barriers comprise material which during use of said device becomes substantially hydrophilic.

1 2. A device as in Claim 1 1 further comprising said reagent liquid containing a component therein to render both of said initially hydrophobic barriers hydrophilic.

1 3. A device as in Claim 1 wherein said reactant is a solute.

1 . A device as in Claim 1 wherein said reactant is a solvent.

1 5. A device as in Claim 5 wherein said chamber contains said reactant in comminuted solid form.

1 6. A device as in Claim 5 wherein said chamber contains comminuted solid material therein, said reactant being disposed as a coating on said material.

1 7. A device as in Claim 5 wherein said chamber contains a porous body therein, said reactant being disposed on or within said porous body.

1 8. A device as in Claim 1 wherein said reactant containment means comprises a barrier disposed across and secured within said conduit, said barrier being permeable to said reagent liquid, with said reactant being disposed within said conduit more proximal to said reservoir than said barrier.

1 9. A device as in Claim 1 8 wherein said barrier is initially hydrophobic.

20. A device as in Claim 1 9 wherein said initially hydrophobic barrier comprises material which during use of the device becomes substantially hydrophilic.

21 . A device as in Claim 20 further comprising said reagent liquid containing a component therein to render said hydrophobic barrier hydrophilic.

22. A device as in Claim 1 8 wherein said reactant is disposed in comminuted solid form.

23. A device as in Claim 1 8 wherein there is disposed between said barrier and said reservoir comminuted solid material and said reactant is disposed as a coating on said material.

24. A device as in Claim 18 wherein there is disposed between said barrier and said reservoir a porous body and said reactant is disposed on or within said porous body.

25. A device as in Claim 1 wherein said reactant containment means comprises a porous solid body secured within said conduit and said reactant is disposed on or within said porous body.

26. A device as in Claim 25 wherein said body is disposed across said conduit.

27. A device as in Claim 25 wherein said body is disposed around a inner surface of said conduit.

28. Pipetting apparatus for collecting and dispensing a standard liquid sample of a control material, which comprises: a walled hollow liquid reservoir with an opening in a wall thereof providing liquid access to said reservoir; a elongated tubular liquid conduit detachably attached to said opening and providing liquid communication between said reservoir and an exterior of said device; liquid transfer means cooperating with said reservoir for alternately drawing a defined volume of reagent liquid into said reservoir from said exterior through said conduit and dispensing a corresponding volume of said liquid sample to said exterior from said reservoir through said conduit; and reactant containment means within said conduit for containing a defined quantity of reactant therein, said reactant being a solute or solvent with a respective solvent or solute contained in said reagent liquid, said solute being rapidly and fully soluble or dispersible in said solvent, and said reactant containment means further permitting flow of said volume of reagent liquid therethrough in contact with said solute, said flow of said reagent liquid thereby contacting said solute and solvent and dissolution or dispersion of said solute in said solvent to form said liquid sample; whereby subsequent dispensing of said formed liquid sample yields a reference material of known properties.

29. Apparatus as in Claim 28 wherein said conduit comprises a detachable pipette tip. -20-

30. Apparatus as in Claim 29 further comprising a container for retaining a detached pipette tip prior to its being attached to said reservoir.

31 . Apparatus as in Claim 30 wherein said container comprises a basin for containing a body of said reagent liquid and retainer means for retaining said detached pipette tip disposed above surface level of said body of reagent liquid when said body is contained in said basin, said pipette tips also being retained in alignment for attachment to said reservoir.

32. Apparatus as in Claim 31 wherein said retainer means is flexible, such that following attachment of said pipette tip is attached to said reservoir flexing of said retainer means with reagent liquid in said basin permits said pipette tip to contact said fluid and said fluid to be drawn into said reservoir.