US3857784A

US3857784A - Apparatus for applying and drying chromatographic samples

Info

Publication number: US3857784A
Application number: US00301583A
Authority: US
Inventors: S Martinez
Original assignee: Sindco
Current assignee: Sindco
Priority date: 1972-10-27
Filing date: 1972-10-27
Publication date: 1974-12-31
Anticipated expiration: 1991-12-31

Abstract

A portable sampling apparatus with intermittent drying action and drying only a defined area of the test surface, having a frame provided with a slot marked with evenly spaced indicia and through which liquid chemical substances or samples may be applied to a surface for chromatographic and other purposes. Air, nitrogen, or any other suitable, known gas is normally directed uniformly through a manifold arranged surrounding the slot and onto the surface for drying the sample. A plate is pivotally mounted on the frame for functioning as a hand rest for an operator applying the sample to a surface, and a projection on the plate is arranged for being biased against a resilient tube forming a part of a fluid flow passage supplying the manifold for blocking the flow passage while a sample is being applied to the surface.

Description

United States Patent 1191 Martinez [11] 3,857,784 1451 Dec. 31, 1974 APPARATUS FOR APPLYING AND DRYING Primary Examiner-John Adee CHROMATOGRAPHIC SAMPLES Attorney, Agent, or Firm-Norbert P. Holler; Bert J. [75] Inventor: Sylvia Martinez, Coral Gables, Fla. Lewen [73] Assignee: SINDCO, Coral Gables, Fla. [57] ABSTRACT 22 i Oct 27 1972 A portable sampling apparatus with intermittent drying action and drying only a defined area of the test [21] Appl 301583 surface, having a frame provided with a slot marked with evenly spaced indicia and through which liquid 52 us. Cl 210/198 chemical substances 91 Samples y be pp to a [51] Int. Cl B01d 15/08 Surface for chromatographic and other P p Air, [58] Field of Search 210/31 0, 198; 117/106 A, nitrogen, or y other suitable, known gas is normally 117 1193; 113 3 directed uniformly through a manifold arranged surrounding the slot and onto the surface for drying the [56] References Cit d sample. A plate is pivotally mounted on the frame for UNITED STATES PATENTS functioning as a hand rest for an operator applying the sample to a surface, and a projection on the plate is gzg gg et a1 2% arranged for being biased against a resilient tube form- 3229505 1/1964 Sanford e i iii i1:11....11l. 210/31 0 mg a of a mud flow Passage Supplying the fold for blocking the flow passage while a sample is being applied to the surface.

11 Claims, 4 Drawing Figures 3/8 so 50 52 I6 22 I2 I 2e 4 APPARATUS FOR APPLYING AND DRYING CHROMATOGRAPHIC SAMPLES BACKGROUND OF THE INVENTION l. Field of the Invention This invention relates generally to sampling apparatus, and in particular to such apparatus used for chrmatographic and other suitable purposes.

2. Description of the Prior Art Chromatography may be defined as a separating of compounds in a solution or mixture by seeping the solution or mixture through an adsorbent. Each compound in the solution or mixture will become adsorbed in a separate, frequently colored layer. This procedure has numerous applications in chemical analysis, and several forms of chromatographic analysis are employed in the chemical arts. Among these forms are paper, thin-layer, and vapor phase chromatography.

In the performance of these chromatographic processes, it is usually necessary to subject a sample to a drying medium immediately upon the deposition of the sample on a sample-receiving or test surface. A relatively complex apparatus is known which automatically applies samples to a test surface in the form of streaks or spots. This known device has a bore arranged beneath the test surface for directing a flow of air thereto for penetrating through the material forming the test surface and drying the samples. However, since the air must pass through the surface forming material, this known device is restricted for use in performing paper chromatography where paper and other porous materials are employed, and is not suitable for use in thinlayer chromatography which employs glass, metal, plastic, and other impermeable materials. Further, this known device cannot be used when it is necessary to provide a flow of a gas other than air as for preventing the sample from oxidizing or to cause the sample to react with a particular gas for a specified purpose.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a time saving, efficiency increasing, simple and reliable apparatus for simultaneously applying and drying liquid chemical samples on various surfaces for chromatographic and other purposes, protecting the sample in the applicator means from being evaporated.

It is another object of the present invention to provide a sampling apparatus with which samples may be protected against oxidation, or purposely oxidized or reacted with an appropriate gas for a specified purpose.

These and other objects are achieved according to the present invention by providing an apparatus for drying samples of a fluid substance which has an arrangement for directing a flow of a drying medium onto a test surface for drying a sample of a fluid substance on the surface, and an arrangement for interrupting the drying medium flow when a sample is being applied to the surface.

In general, the apparatus includes a base structure adapted to be supported on a table top or the like and providing a defined area which is accessible from above and within the confines of which a sample-receiving portion of the test surface may be located. The base structure further provides a conduit system for directing a flow ofa drying gas from an intake section of the system to a discharge section at the test surface location, and means are provided for establishing communication between a source of drying gas under pressure and the intake section of the conduit system and for regulating the flow of drying gas into the conduit system and for regulating the flow of drying gas into the conduit system. The latter includes, intermediate the intake and discharge sections thereof, an open-shut valve arrangement actuatable from above, and a manually displaceable operating member having a valveengaging adjunct thereon is hinged to the base structure in overlying relation to the valve arrangement, so that only when an operator rests his hand on the operating member and depresses the same, the valve arrangement is closed. In this manner, the flow of drying gas can be interrupted by the operator resting on the operating member the hand in which he is holding the liquid applicator, so that during the application of each sample to the test surface, drying of the liquid substance in the applicator device is prevented, while drying of the samples can then, simply by the lifting of the operators hand, be commenced immediately after the application of the sample to the test surface.

A preferred embodiment of an apparatus according to the present invention has a frame provided with an opening in the form of a slot for defining an area in which a sample is applied to a test surface. This frame includes a pair of members arranged for cooperating when placed together to form the slot and the drying medium flow directing arrangement. The directing arrangement advantageously has a manifold surrounding the slot, and grooves provided in one of the members. A piece of resilient tubing is arranged in an opening provided in the member having the grooves so as to form a portion of a flow passage between the fluid source and the manifold. The interrupting arrangement has a projection which is arranged for selectively engaging the tubing and blocking the flow passage.

Preferably, the tube blocking projection is provided on a plate pivotally mounted to the frame and arranged for engagement by a hand of an operator applying a sample to the sample surface for biasing the projection against the tubing and blocking the flow passage while the sample is being applied.

The member not provided with the fluid passage grooves advantageously has a planar portion in which a portion of the slot and the tubing receiving opening are arranged, and depending side wall portions extending transversely with respect to the planar surface for supporting the apparatus on a suitable supporting member such as a table top. Recesses are formed in the side wall portions for receiving an article such as a pipette, glass rod, and the like for separating a film forming a test surface from the supporting member. This will prevent seepage when using a porous material such as a paper or other material constructed from a glass fiber or other porous material as the film.

Samples may be applied and dried to a test surface according to the method of the present invention by directing a flow of drying medium directly onto a receiving test surface for drying a sample of a fluid substance on the surface, applying selectively a sample to the test surface as by an operator resting a hand on the pivotally mounted plate and wetting the test surface with a fluid substance from a pipette and the like, and inter rupting the drying medium flow when a sample is being applied as by the pressure of the hand on the pivotally mounted plate blocking the resilient tubing forming part of the flow passage. Thus the drying action is stopped while the sample is being spotted on the test surface and reinitiated when the sampling means is raised.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part thereof, wherein like numerals refer to like parts throughout.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary, perspective view showing a sample applying and drying apparatus according to the present invention.

FIG. 2 is an exploded, perspective view showing the apparatus of FIG. 1.

FIG. 3 is a fragmentary, sectional view taken generally along the line 3-3 of FIG. 1.

FIG. 4 is a fragmentary, sectional view showing a detail of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now more particularly to the drawings, there is shown an apparatus according to the present invention for applying and drying samples of a fluid substance such as a solution or mixture. This apparatus 10 has a conduit system or arrangement 12 (FIG. 3) for directing a flow of a drying medium onto a test surface 14 for drying a sample 16 (FIG. 3) of a fluid substance deposited on surface 14in a manner to be discussed below. Apparatus 10 also has an arrangement 18 for interrupting the drying medium flow when a sample 16 is being applied to the surface 14.

Apparatus 10 is shown as having a frame or base structure 20 provided with an opening in the form of a slot 22 for defining an area in which a sample 16 is applied to surface 14. Frame 20 includes a pair of

members

24 and 26 arranged for cooperating when placed together to form slot 22 and the conduit system or arrangement 12. Member 24 may be referred to as an upper plate, and member 26 as a lower plate. Arrangement 12 includes a manifold 28 surrounding slot 22 and formed as by spaced projections 29 extending from the bottom of a recess in member 26, and grooves 30 (FIG. 2) also provided in member 26.

Arrangement 12 also includes an open-shut valve constituted, in the illustrated embodiment of the invention, of a section of tubing 32 constructed from a resilient material such as a synthetic rubber and forming a flow passage in cooperation with grooves 30. Arrangement 18 is provided with a projection 34 arranged for selectively engaging tubing 32 and blocking its flow passage. An opening 36 is provided in member 24 for receiving tubing 32. Selective blocking of the passage way of tubing 32 is achieved by a cover plate or operating member 38 pivotally mounted on member 24 of the base structure as by conventional hinges 40. Projection 34 is mounted on the surface of plate 38 adjacent member 24. Plate 38 is arranged for engagement by a hand (not shown) of an operator applying a sample 16 as by a pipette and the like to surface 14 for biasing projection 34 against tubing 32 and blocking the flow passage of tubing 32 while a sample 16 is being applied. Tubing 32 is mounted to

members

24, 26 as by a pair of fittings 42 formed from two

parts

44 and 46. Part 44 is illustrated as integral with member 24, and part 46 as integral with member 26. When the plates or

members

24, 26 are arranged abutting one another,

parts

44 and 46 will cooperate to form fittings 42. Tubing 32 may he slipped over fittings 42 in a conventional manner and be retained thereon as by the pointed, annular gripping members. Portions of plate or member 26 are removed to permit tubing 32 to fit over fitting parts 46. A web 48 is left between these cut out portions to provide an abutment surface cooperating with projection 34 to block the passageway of tubing 32. The intake section of the conduit system, at the end of grooves 30 most distant from the discharge section or manifold 28, is adapted to be attached to a suitable, known gas flow regulating valve 50. This valve 50 may in turn be connected to a hose leading from a suitable, known source of an appropriate gas under pressure. Member 24 has a planar portion 52in which opening 36 and its portion of slot 22 are arranged, and depending side wall portions 54 extending transversely with respect to planar portion 52 for supporting the apparatus on a suitable supporting member 56. Member 56 may be a table top and the like. Side wall portions 54 have formed therein recesses 58 for receiving an article 60 such as a pipette, glass rod, and the like for separating a film 62 forming test surface 14 from supporting member 56 when film 62 is, for example, a paper constructed from glass fiber or some other porous material. This will prevent seepage of the liquid sample through the porous material and onto the supporting member 56. This separation is not necessary when a thin layer sheet having glass, metal, plastic, and the like backing is used.

It is to be understood that although any suitable, known valve 50 may be employed with an apparatus 10 according to the present invention. valve 50 forms part of the invention and is selectively connectible to a hose (not shown) for connection to an appropriate source of pressurized gas. The numbering illustrated in FIGS. 1 and 2 between slot 22 and the edge of member 24 is only exemplary, and it is to be understood that other appropriate markings may be used if desired. The markings without indicia on the other longitudinal side of slot 22 are advantageously placed in an alternate manner to the first-mentioned markings.

Plate members

24 and 26 may be assembled in a suitable, known manner, as by gluing with a suitable, known adhesive. Further, article 60 should be selected of a diameter sufficient small as to allow for ample space between it and plate or member 26. This is so a chromatographic test surface such as film 62 can be placed between article 60 and member 26 in such a manner that film 62 does not press against the adjacent surface of member 26, but only just touches it.

In operation, a chromatographic-surface such as film 62 is placed under apparatus 10 in such a way that a sample application line on film 62 is arranged at the center of slot 22. Air or any other appropriate gas is allowed to enter apparatus 10 through valve 50, which may be adjusted to regulate the gas flow. Liquid sample drops are deposited through the aperture formed by slot 22 and onto the surface 14 of film 62 in a sequential manner in such a way that when the small volume of liquid drop is deposited on surface 14 by means of a micropipette or any other similar supporting device (not shown), the weight ofa hand on plate 38 stops the gas flow. Removal of the hand from plate 38 restores the gas flow. Once the gas flow is restored, the spotted sample 16 is immediately evaporated or dried in a uniform manner so that dispersion of the area occupied by sample 16 on surface 14 is either reduced to a minimum or completely eliminated. This sequence is continued until all the appropriate samples have been spotted.

Manifold 28 is designed specifically to provide a uniform flow of gas through all and each one of its plurality of openings and into slot 22. In this manner, all samples are dried at the same rate. The channels-that is, the recess and the grooves 30-in member 26 are shown exaggerated for clarity. In actuality, they would be, for example, 15 to thousandths of an inch deep.

An apparatus 10, which may be referred to as a sampler or sample applicator, according to the present invention is advantageously constructed from materials resistant to most chemicals and solvents. This may be achieved as by, for example,

molding members

24, 26 from appropriate synthetic resin. Recesses 58, which are preferably in the form of semi-circles, allow the use of articles 60 which are commonly and conveniently found in chemical laboratories. The markings and indicia on the edge of slot 22 allow even spacing with identification of samples according to a predetermined number. Any lightweight surface commonly used for chromatography or any other similar purpose is held down in place by apparatus 10 not is now blown by the gas flow, an occurrence common with conventional, known dryers of this type.

An apparatus 10 according to the present invention is designed to provide an even flow of gas throughout the entire aperture of slot 22, thus allowing a fast, even drying or evaporation of an applied liquid sample drop. Suitable hot gases may be used to accelerate the evaporation of the sample, and suitable inert gases, such as nitrogen and the like, may be used for protection of unstable samples. Reactive gases may be used to produce chemical changes on the applied sample, in situ. The gas flow may be actuated at will while the liquid sample is being applied merely by lifting the hand from plate 38. Since there is usually no gas flow while the liquid sample is being applied, there is practically no evaporation of the sample in the micropipette or other sampling device being used. This evaporation is practically unavoidable when using conventional dryers and can be of critical importance when running quantitative runs with volatile solvents. Since the evaporation or drying of the sample is obtained so easily and uniformly, the application of a sample can be made in smaller amounts, producing smaller spot areas which give better definition and separation.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.

. What is claimed as new is as follows:

1. A simple, portable, manually actuatable apparatus for use in the application to a chromatographic test surface, and in the drying on the test surface, of one or more samples ofa liquid substance to be dried and analyzed, comprising, in combination:

a. a base structure adapted to be supported on a table top or the like and providing i. a defined area within the confines of which a sample-receiving portion of the test surface may be located, and

ii. a conduit system for directing a flow of a drying gas from an intake section of said conduit system to a discharge section thereof at said defined area and there to each location of a sample on the test surface, said conduit system including an openshut valve means intermediate said intake and discharge sections and positioned for actuation from exteriorly of said base structure;

b. means for establishing communication between said intake section of said conduit system and a source of drying gas under pressure and including means for regulating the flow of drying gas into said conduit system; and

c. a manually displaceable operating member hingedly connected to said base structure, said operating member having an adjunct arranged to operate said valve means'so as to close the latter when said operating member is engaged and pressed toward said base structure by the hand of an operator;

d. whereby the flow of drying gas to said defined area can first be interrupted by the hand of the operator while a sample is being applied to the test surface and can then be renewed simply by the lifting of the operators hand, so that i. drying of the portion of the liquid substance which remains in the applicator device during the application of each sample to the test surface is prevented, and

ii. drying of the sample can nevertheless be commenced immediately after the application thereof to the test surface.

2. A simple, portable, manually actuatable apparatus for use in the application to a chromatographic test surface, and in the drying on the test surface, of one or more samples of a liquid substance to be dried and analyzed, comprising, in combination:

a. a base structure adapted to be supported on a table top or the like and providing i. a defined area which is accessible from above and within the confines of which a sample-receiving portion of the test surface may be located, and

ii. a conduit system for directing a flow of a drying gas from an intake section of said conduit system to a discharge section thereof at said defined area and there to each location of a sample on the test surface, said conduit system including an openshut valve means intermediate said intake and discharge sections and positioned for actuation from above;

c. a manually displaceable operating member overlying the top of said base structure and hingedly connected thereto, said operating member having an adjunct arranged to operate said valve means so as to close the latter when said operating member is engaged from above and pressed down toward said base structureby the hand of an operator holding an applicator device;

(1. whereby the flow of drying gas to said defined area can first be interrupted by the hand of the operator while a sample is being applied to the test surface and can then be renewed simply by the lifting of an operators hand, so that i. drying of the portion of the liquid substance which remains in the applicator device during the application of each sample to the test surface is prevented, and

3. An apparatus according to claim 2, wherein said base structure comprises a horizontal plate member provided with a slot-shaped opening which constitutes said defined area and beneath which said samplereceivirig portion of the test surface may be located.

4. An apparatus according to claim 3, wherein said conduit system at said discharge section thereof includes a manifold providing a plurality of outlet apertures for admitting drying gas into said slot-shaped opening at a corresponding plurality of locations.

5. An apparatus according to claim 2, wherein said open-shut valve means comprises a length of resilient, flexible tubing supported on said base structure and defining an interior passageway which is a part of said conduit system, and said operating member is mounted so as to have said adjunct thereof engage and compress said tubing for closing said passageway when said operating member is pressed toward said base structure.

6. An apparatus according to claim 2, wherein said base structure comprises first and second horizontal plate members located one atop the other, each of said plate members being provided with a respective slotshaped aperture, said apertures being vertically aligned with one another and together forming a slot-shaped opening which constitutes said defined area and beneath which said sample-receiving portion of the test surface may be located, and said plate members at their abutting surfaces being cooperatively constructed to define said conduit system with said discharge section thereof in communication with said slot-shaped open- 8 ing.

7. An apparatus according toclaim 6, wherein the upper one of said plate members has a second opening therein located above an imperforate portion ofa lower one of said plate members, said plate members cooperatively define a pair of fittings extending into said second opening, said open-shut valve means comprises a length of resilient, flexible tubing overlying said imperforate portion of said lower plate member and connected at its opposite ends to said fittings and defining a normally open interior passageway which is a part of said conduit system, and said operating member is mounted so as to have said adjunct thereof engage and compress said tubing against said imperforate portion of said lower plate member for closing said passageway when said operating member is pressed sufficiently far down toward said upper plate member.

8. An apparatus according to claim 7, wherein said operating member is a third plate member hinged at one edge to one of said upper and lower plate members and having on its surface directed toward said upper plate member a projection constituting said adjunct and adapted to enter said second opening for engagement with said tubing.

9. An apparatus according to claim 8, wherein said third plate member is hinged on said upper plate memher at a location remote from said slot-shaped opening.

10. An apparatus according to claim 9, wherein said upper plate member has a pair of downwardly depending opposed side walls, said lower plate member fits into the space between said side walls, and said side walls are provided with respective recesses aligned with one another below the level of the bottom surface of said lower plate member to define a space for insertion of an elongated member therethrough adapted to underlie and support a test surface element beneath said slot-shaped opening.

11. An apparatus according to claim 10, wherein said upper plate member has markings alongside said slotshaped opening to designate locations for the application of plural samples to the test surface.

* l l I

Claims

1. A simple, portable, manually actuatable apparatus for use in the application to a chromatographic test surface, and in the drying on the test surface, of one or more samples of a liquid substance to be dried and analyzed, comprising, in combination: a. a base structure adapted to be supported on a table top or the like and providing i. a defined area within the confines of which a samplereceiving portion of the test surface may be located, and ii. a conduit system for directing a flow of a drying gas from an intake section of said conduit system to a discharge section thereof at said defined area and there to each location of a sample on the test surface, said conduit system including an open-shut valve means intermediate said intake and discharge sections and positioned for actuation from exteriorly of said base structure; b. means for establishing communication between said intake section of said conduit system and a source of drying gas under pressure and including means for regulating the flow of drying gas into said conduit system; and c. a manually displaceable operating member hingedly connected to said base structure, said operating member having an adjunct arranged to operate said valve means so as to close the latter when said operating member is engaged and pressed toward said base structure by the hand of an operator; d. whereby the flow of drying gas to said defined area can first be interrupted by the hand of the operator while a sample is being applied to the test surface and can then be renewed simply by the lifting of the operator''s hand, so that i. drying of the portion of the liquid substance which remains in the applicator device during the application of each sample to the test surface is prevented, and ii. drying of the sample can nevertheless be commenced immediately after the application thereof to the test surface.

2. A simple, portable, manually actuatable apparatus for use in the application to a chromatographic test surface, and in the drying On the test surface, of one or more samples of a liquid substance to be dried and analyzed, comprising, in combination: a. a base structure adapted to be supported on a table top or the like and providing i. a defined area which is accessible from above and within the confines of which a sample-receiving portion of the test surface may be located, and ii. a conduit system for directing a flow of a drying gas from an intake section of said conduit system to a discharge section thereof at said defined area and there to each location of a sample on the test surface, said conduit system including an open-shut valve means intermediate said intake and discharge sections and positioned for actuation from above; b. means for establishing communication between said intake section of said conduit system and a source of drying gas under pressure and including means for regulating the flow of drying gas into said conduit system; and c. a manually displaceable operating member overlying the top of said base structure and hingedly connected thereto, said operating member having an adjunct arranged to operate said valve means so as to close the latter when said operating member is engaged from above and pressed down toward said base structure by the hand of an operator holding an applicator device; d. whereby the flow of drying gas to said defined area can first be interrupted by the hand of the operator while a sample is being applied to the test surface and can then be renewed simply by the lifting of an operator''s hand, so that i. drying of the portion of the liquid substance which remains in the applicator device during the application of each sample to the test surface is prevented, and ii. drying of the sample can nevertheless be commenced immediately after the application thereof to the test surface.

3. An apparatus according to claim 2, wherein said base structure comprises a horizontal plate member provided with a slot-shaped opening which constitutes said defined area and beneath which said sample-receiving portion of the test surface may be located.

6. An apparatus according to claim 2, wherein said base structure comprises first and second horizontal plate members located one atop the other, each of said plate members being provided with a respective slot-shaped aperture, said apertures being vertically aligned with one another and together forming a slot-shaped opening which constitutes said defined area and beneath which said sample-receiving portion of the test surface may be located, and said plate members at their abutting surfaces being cooperatively constructed to define said conduit system with said discharge section thereof in communication with said slot-shaped opening.

7. An apparatus according to claim 6, wherein the upper one of said plate members has a second opening therein located above an imperforate portion of a lower one of said plate members, said plate members cooperatively define a pair of fittings extending into said second opening, said open-shut valve means comprises a length of resilient, flexible tubing overlying said imperforate portion of said lower plate member and connected at its opposite ends to said fittings and defining a normally open interior passageway which is a part of said conduit system, and said operatinG member is mounted so as to have said adjunct thereof engage and compress said tubing against said imperforate portion of said lower plate member for closing said passageway when said operating member is pressed sufficiently far down toward said upper plate member.

9. An apparatus according to claim 8, wherein said third plate member is hinged on said upper plate member at a location remote from said slot-shaped opening.

11. An apparatus according to claim 10, wherein said upper plate member has markings alongside said slot-shaped opening to designate locations for the application of plural samples to the test surface.