Fluent material handling – with receiver or receiver coacting mea – With conveying means to supply successive receivers – Sampler type
Reexamination Certificate
2000-03-08
2001-06-05
Douglas, Steven O. (Department: 3751)
Fluent material handling, with receiver or receiver coacting mea
With conveying means to supply successive receivers
Sampler type
C141S129000, C422S105000
Reexamination Certificate
active
06240984
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to automated liquid handlers and more particularly to an improved probe assembly having a foot seal for sealing the interface between the probe foot and the tops of sample containers accessed by the probes of the probe assembly
DESCRIPTION OF THE PRIOR ART
Automated liquid handlers are used for handling laboratory samples in a variety of laboratory procedures. In solid phase extraction (SPE) procedures, a solid medium in a sample container is covered with a liquid that is introduced into the container by a probe, and the liquid is removed from the container through a sorbent packing covering a discharge passage at the bottom of the sample container. Although the liquid can be permitted to drain using only the force of gravity, this is a slow process and prevents high throughput automated SPE analysis.
In order to increase the speed of the SPE procedure, a pressure differential can be applied so that the interior of the sample container is at a higher pressure than the region outside the container discharge passage As a result, the liquid discharge flow rate is increased. The desired pressure differential can be imposed by application of vacuum to the region below the sample containers. However a more effective and more precisely controlled approach is to apply increased pressure within the containers. This can be done by using a probe having two axially extending passages, one for the liquid to be introduced into the sample container, and another for the introduction of a pressurized inert gas for pressurizing he container.
In order to permit an elevated pressure within the container, the top of the container must be sealed from the surrounding atmosphere. In addition, the probe must be able to enter the container without interfering with the sealing effect. Sample containers of many configurations and sizes are available, ranging from tubes or vessels of various cross sectional shapes to microplates having numerous sample containing wells in arrays having, for example, 96 or 384 wells. It would be desirable to provide a probe assembly able to provide a seal with many different types of sample container. A further difficulty arises from the fact that liquid handlers can be provided with multiple probes, such as eight probes, that simultaneously operate with a similar number of sample containers. An effective probe assembly sealing arrangement should be able to accommodate both single and multiple probe arrangements with various numbers of probes at various centerline spacings.
One approach that has been used in the past is to mount a sealing member on the probe so that when the probe is inserted into a sample container, the seal member also enters the container to provide a seal between the probe and the inner wall of the container. For multiple probe assemblies, each probe is supplied with a discrete seal member. The difficulty with this approach is that the seal body, or each seal body in a multiple probe system, must mate precisely with the sample containers. The seals and sample containers must be uniform in size and shape. The seal body cannot be used with other types of sample containers having different shapes or sizes.
Another approach that has been used in the past is to manually insert a seal body into the top of each sample container. These seal bodies have apertures through which the probe can be inserted into the sample container. After the probe is inserted, the seal body provides a seal between the probe and the wall of the container. A difficulty with this approach is that the seal insertion step requires slow and burdensome manual labor. In addition, the seal bodies must be matched to specific container types.
SUMMARY OF THE INVENTION
A principal object of the present invention is to provide an improved foot seal for automated liquid handlers. Other objects are to provide a foot seal that functions without alteration or special preparation with sample containers of many types, sizes and shapes; to provide a foot seal that is self sealing without special preparative steps; to provide a foot seal that is easily and replaceably mounted on a probe foot; and to provide an automated liquid handler having a probe foot seal overcoming disadvantages of probe sealing systems used in the past.
In brief, in accordance with the invention there is provided a solid phase extraction probe assembly for use with a sample container having a horizontal container top surface. The assembly includes a vertically extending, elongated probe and a foot defining a probe receiving passage extending from the top to the bottom of the foot. Support means for supports the foot, and drive means moves the support means and the foot relative to the sample container array, and moves the probe axially through the foot receiving passage in the foot. A foot seal is attached to the bottom of the foot, the foot seal having a probe receiving opening aligned with the probe receiving passage. The foot seal has an upper surface in sealing relation against the bottom surface of the foot and a lower surface engageable in sealing relationship with the container top surface.
REFERENCES:
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patent: 4265855 (1981-05-01), Mandle et al.
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patent: 4669321 (1987-06-01), Meyer
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patent: 4962041 (1990-10-01), Roginski
patent: 5935523 (1999-08-01), McCandless et al.
Fawcett Kevin Richard
Hlavachek John Paul
Schultz Craig A.
Douglas Steven O.
Gilson, Inc.
Huynh Khoa
Kolehmainen Philip M.
Mason, Kolehmainen Rathburn & Wyss
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