Spotting Device

Abstract

A spotting device for depositing samples of urine, urine extracts or blood, for example, in an organic or inorganic solvent on chromatographic plates or sheets. The device includes a holding bar, adapted to receive a plurality of disposable funnels therethrough, each funnel providing an open top, above the holding bar for reception of a sample, and a small orifice in its lower end, below the holding bar, for depositing the sample on a chromatographic plate or sheet which is carried on a heating bar which is manually set to a predetermined degree of temperature. The carrying plate is pivotal from a raised position to a position wherein the lower tip ends of the funnels are in tight contact with the chromatographic plate or sheet on the heating bar. The funnels are preferably formed of an inexpensive synthetic material such as polyethylene and are intended for one-time use.

Description

STATE OF THE PRIOR ART

Samples to be spotted are normally carried in an organic or inorganic solvent and when spotting more than one microliter, the spots must be dried, that is the solvent must be removed by heat means.

Many ways have been devised for automatically spotting samples on chromatographic plates or sheets including equipment containing motor driven syringes. Another way is to use serrated plastic instruments which have small teeth for dipping into the fluid. The fluid adheres to the teeth, and when the teeth are moved into engagement with a chromatographic plate or sheet, the fluid containing the sample is deposited thereon.

Still another method utilizes wicks wherein a small beaker of the compound to be spotted has a wick placed therein with an extending end in contact with a chromatographic sheet. As the liquid compound passes through the wick from the beaker to provide a spot on the sheet, the solvent is being evaporated.

BACKGROUND OF THE PRESENT INVENTION

The present invention pertains to a device for spotting one or more samples of urine, urine extracts or blood, for example, on a chromatographic plate or sheet, the sample or samples being carried in an organic or inorganic solvent.

One or more disposable funnels are insertable through holes in a carrier bar which is pivotal by handle means between a raised position and a locked, lower position. One funnel is placed through the carrier bar for each sample to be spotted; each funnel provides a relatively large open upper end, above the carrying bar, and a tapered lower end providing a relatively small opening at the bottom tip and thereof, below the carrier bar. When the carrier is in its locked, lower position, the bottom tip ends of the funnels in the carrier bar are normally held tightly against the top surface of a heating bar.

In use, the carrying bar is raised and a chromatographic sheet is placed on top of the heating bar, the carrying bar is locked in its lower position with the bottom tip ends of the funnels tightly held against the chromatographic sheet on the heating bar, the heat being set to a predetermined degree by manual heat control means. Using a pipette, the sample compounds are then placed in the respective funnels.

The absorbent chromatographic sheet receives the samples and, at the same time, the heating bar evaporates the solvent leaving only the samples on the chromatographic sheet.

The funnels are constructed so that the sample compounds contained therein do not boil and splatter and are disposable after a one-time use. In practice, the funnels are very inexpensively formed of a synthetic material such as polyethylene, and the like although other plastics such as polypropylene, Delrin, may be used.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top plan view of the spotting device of the present invention;

FIG. 2 is a longitudinal sectional view taken along the line 2--2 of FIG. 1;

FIG. 3 is a transverse sectional view taken along the line 3--3 of FIG. 1;

FIG. 4 is a vertical sectional view through a typical funnel utilized by the present invention; and

FIG. 5 is a bottom view of the funnel of FIG. 4.

DETAILED DESCRIPTION OF THE DRAWINGS

With reference to the drawings in which like reference characters designate like or corresponding parts throughout the various views, the numeral 10 designates the spotting device of the present invention which is comprised generally of a housing 12 forming an interior chamber 14 containing a heating element and bar means 16 and electronic control means 18. Manual control means 20 are mounted exteriorly of a front housing panel 22. A transverse sample carrying bar 24, for a plurality of disposable sample funnels 26 is pivotally mounted at 28 exteriorly of the rear end of the housing 12 and a combination handle and lock means 30 is, in turn, pivotally mounted at 32 to the sample carrying bar 24.

In addition to the front panel 22, the housing includes bottom and rear panels 34 and 36 formed integral therewith with an electric lead 38 to the electronic control means extending through the rear panel 36. The housing is completed by an integrally formed top cover panel 40 and opposed side panels 42 and 44 fixed by screw means 46 to respective upstanding edge flanges 48 and 50 from the bottom panel 34. Four rubber feet 52 are fixed in a conventional manner to the bottom panel 34.

With particular reference to FIGS. 2 and 3, the heating element and bar means 16 is mounted interiorly of the chamber 14, adjacent the rear panel 36, on a pair of spaced apart steel leaf springs 54 and 56. As best illustrated in FIG. 2, each leaf spring 54 and 56 is fixed by screws 58 at its opposed ends to a pair of ceramic insulators 60 and 62 which are, in turn, fixed by screws 64 to the bottom web 66 of a hinge and mounting bracket 68, fixed interiorly of the chamber 14 in any conventional manner.

A heating element 70 is sandwiched between bottom and top heating bars 72 and 74 which are fixed in assembly in spanning relation to the mid-sections of the leaf springs 54 and 56 as by screws (not shown). The top surface 76 of the top heating bar 74 projects through an opening 78 in the top panel 40 in a generally coplanar relation therewith.

The manual control means 20 for the electronic control means 18 includes an on-off switch 80, a calibrated temperature control dial and knob 82, and pilot light means 84 which indicates that the "set" temperature has been reached.

A pair of opposed side webs 86 and 88 of the hinge and mounting bracket 68 terminate in enlarged, rearwardly extending end portions 90 and 92 above the top panel 40. The sample carrying bar 24 spans the distance therebetween and is pivotally attached thereto, adjacent its rear end, as by a pair of shoulder screws 94 and 96 comprising the pivotal mounting 28.

Handle and lock means 30 is comprised of a pair of opposed bell crank levers 98 and 100, each of which is pivoted at its apex on a shoulder screw 102, and a transverse handle 104 fixed by screws 106 and 108 between the ends of the first bell crank arms 110 and 112. The shoulder screw pivots 102 are threaded into the opposed front side portions of the sample carrying bar 24. A hook 114 is formed at the end of each of the second bell crank arms 116 which is arranged to engage the shank portion of a shoulder screw 118, threaded through a side wall 42 or 44, into an extension 120 of one of the side webs 86 or 88.

Rearwardly of and adjacent to the front edge of the sample carrying bar 24, a plurality of transversely aligned holes 121 are formed therethrough to receive a like plurality of disposable sample funnels 26. Each funnel 26, as best illustrated in FIGS. 4 and 5, includes an upper portion 122 which is sized to be snugly received upwardly through one hole 121 and to project upwardly somewhat beyond the top of the carrying bar 24 with a shoulder flange 124 seated against the underside thereof. The upper portion 122 provides a uniform diameter chamber 126 opening downwardly into an elongated small diameter chamber 128 in a tapered spout portion 130 extending downwardly from the flange 124. A relatively small orifice 132 opens through the bottom tip end 134 into the chamber 128.

With particular reference to FIG. 2, the handle and lock means assembly 30 is illustrated in full lines in its locked down position with the tip ends 134 bearing tightly against the top surface of the upper heating bar 74 against the spring forces of the leaf springs 54 and 56. The upper transverse edges of the upper heating bar 74 are insulated relative to the top panel 40 by asbestos strips 136 and 138. In the dot-dash illustration of the handle and lock means 30', the bell crank levers 98 and 100 are pivoted about the shoulder screws 102 to an unlocked position. The broken line illustration thereof 30" illustrates the sample carrying bar 24 after it has been pivoted about the shoulder screws 94 and 96 to a raised position relative to the top heating bar 74.

In use, the handle 104 is raised sufficiently to permit a chromatographic sheet to be placed on the top heating bar 74. The switch 80 is turned on to warm the heating bars to a degree, determined by the manually operated temperature control dial 82. When the pilot light means 84 indicates that the desired temperature has been attained, it is ready for use.

With the sample carrying bar 24 in its locked position, a pipette is used to place the sample liquid in the disposable funnels, using one or more simultaneously. The sample liquid spots the chromatographic sheet and the solvent is evaporated by the heat.

In practice, the funnels 26 are designed with the elongated, small diameter lower chambers 128 to keep the sample as far away from the heat as possible during the period that said sample is being absorbed by the chromatographic sheet so that said sample does not get hot enough to boil. If the sample boils, it spatters about resulting in a mess. The funnels are formed of a synthetic material such as polyethylene which can be readily and very inexpensively molded and are intended for one-time use whereupon they are discarded.

Claims

What is claimed is:

1. A spotting device for depositing a sample of urine, urine extracts or blood, for example, on a chromatographic sheet comprising:

A. a housing;

B. a heating element mounted in said housing;

C. heating bar means associated with said heating element;

D. a sample carrying bar;

E. disposable funnel means including,

1. an upper portion extending through said sample carrying bar, providing an upper chamber opening outwardly of the top of said sample carrying bar,

2. a shoulder flange for seated engagement against the bottom of said sample carrying bar,

3. a lower portion extending below said sample bar providing an elongated, reduced diameter lower chamber opening downwardly from said upper chamber and terminating in a small discharge orifice through its lower tip end;

F. means to move said sample carrying bar to selectively position said tip end into or out of engagement with a chromatographic sheet, positioned on said heating bar means; and

G. means to lock said tip end in tight engagement against the chromatographic sheet.

2. A spotting device as defined in claim 1 including selective, manual temperature control means for said heating element.

3. A spotting device as defined in claim 1 wherein said lower chamber is in the form of a relatively small diameter through hole terminating at its lower end in said small discharge orifice.

4. A spotting device as defined in claim 1 wherein said disposable funnel means is molded of an inexpensive synthetic material such as polyethylene.

5. A spotting device as defined in claim 1 including a plurality of said disposable funnel means in a spaced-apart relation.

6. A spotting device as defined in claim 5 wherein each of said disposable funnels projects a predetermined distance above said sample carrying bar.

7. A spotting device as defined in claim 5 wherein said heating bar means comprises upper and lower heating bars with said heating element sandwiched therebetween.

8. A spotting device as defined in claim 7 wherein said plurality of funnel means are individually, removably disposed through respective holes in said sample carrying bar whereby the tip ends of a preselected number thereof can be simultaneously locked in tight engagement against a chromatographic sheet disposed on top of said upper heating bar.

9. A spotting device as defined in claim 1 wherein said heating element and heating bar means are resiliently mounted in said housing on spring means.

10. A spotting device as defined in claim 9 wherein said means to move comprises a first pivot attachment between opposed upper extensions of a bracket fixed to said housing and the rear end portion of said sample carrying bar, and a second pivot attachment between a handle means and the front end portion of said sample carrying bar.

11. A spotting device as defined in claim 10 wherein said handle means comprises a pair of opposed side levers attached to said sample carrying bar by said second pivot means and a transverse handle fixed between the respective ends of first arms thereof.

12. A spotting device as defined in claim 11 wherein each of said levers includes a second arm having a hook shaped end portion, adapted to lockingly engage a projection from said housing to maintain said tip ends in tight engagement with the chromatographic sheet on said heating bar means against the forces of said spring means.