Method and apparatus for effecting automated movement of a magnet in an instrument for performing a magnetic separation procedure

1. An apparatus comprising:

a fluid transfer device comprising a plurality of aspirator probes, each aspirator probe having a distal end, and each distal end being adapted to have a conduit mounted thereon;

a slide configured for linear translation between a first position and a second position in the apparatus and having a bottom plate comprising a plurality of conduit stripping elements formed therein, the slide including a first wall and a second wall extending upwardly from the bottom plate and defining a slot between the first and second walls, wherein the slot is configured to receive the plurality of aspirator probes, and wherein the plurality of conduit-stripping elements are disposed in a bottom surface of the slot each conduit-stripping element being associated with a corresponding one of the plurality of aspirator probes, and each conduit-stripping element being adapted to remove a conduit from the distal end of an associated aspirator probe that is aligned with the conduit-stripping element, wherein the plurality of conduit-stripping elements are movable with the slide, such that when the slide is in the first position, no conduit-stripping element is aligned with an aspirator probe to strip the conduit mounted thereon, and when the slide is in the second position, each conduit-stripping element is aligned with the associated aspirator probe, and wherein each conduit stripping element comprises a key-hole opening having a first portion with a transverse size sufficient to permit the conduit to pass therethrough and a second portion with a transverse size sufficient to permit the probe to pass therethrough, but not sufficient to permit the conduit to pass therethrough; and

a controller configured to:

cause the fluid transfer device to pass the distal end of the probe with the conduit disposed thereon through the first portion of the key-hole opening;

effect a linear translation of the slide so that the probe is in the second portion of the key-hole opening; and

withdraw the probe from the key-hole opening, the conduit being retained by the conduit-stripping element when the conduit is unable to pass through the second portion of the key-hole opening.

2. The apparatus of claim 1 , further comprising a receptacle carrier configured to carry a receptacle device in an operative position with respect to the aspirator probes, wherein the receptacle carrier includes an orbital mixer assembly configured to impart an orbital motion to a receptacle device carried by the receptacle carrier.

3. The apparatus of claim 2 , wherein the receptacle device comprises a plurality of receptacles, each receptacle being associated with one of the plurality of aspirator probes.

4. The apparatus of claim 1 , wherein said fluid transfer device further comprises a probe moving mechanism adapted to move the plurality of aspirator probes in unison with respect to the associated receptacles.

5. The apparatus of claim 1 , further comprising a guide structure for supporting said slide for linear translation between said first and second positions and a slide moving mechanism adapted to effect powered linear translation of said slide between said first and second positions.

6. The apparatus of claim 5 , wherein said slide moving mechanism comprises:

a motor;

a threaded drive screw coupled to an output shaft of said motor; and

a screw follower mounted to said slide, wherein said drive screw is engaged with said screw follower such that powered rotation of said drive screw by said motor causes linear translation of said slide.

7. The apparatus of claim 5 , wherein said slide moving mechanism comprises:

a motor with a drive pulley mounted to an output shaft thereof;

an idler pulley; and

a drive belt carried on said drive pulley and said idler pulley and attached to said slide to transfer powered rotation of said drive pulley to linear translation of said slide.

8. The apparatus of claim 1 , comprising a plurality of said aspirator probes, wherein the conduit-stripping elements are arranged in a staggered configuration so that when the plurality of aspirator probes are moved with respect to the plurality of conduit-stripping elements, the conduit-stripping elements sequentially remove the conduits from the associated aspirator probes one at a time.

9. The apparatus of claim 1 , further comprising one or more magnets carried by the slide.

10. A method for removing a conduit from a distal end of each of a plurality of fluid transfer probes, comprising:

effecting powered linear translation of a slide in a direction transverse to the axes of the probes to move conduit-stripping portions of the slide from first locations to second locations, wherein the slide includes a bottom plate comprising the plurality of conduit stripping portions formed therein, the slide including a first wall and a second wall extending upwardly from the bottom plate and defining a slot between the first and second walls, wherein the slot is configured to receive the plurality of aspirator probes, wherein when the conduit-stripping portions are in the first locations, no conduit-stripping portion is in a position to be engaged by any of the probes, and when the conduit-stripping portions are in the second locations, the conduit-stripping portions are in positions to be engaged by the distal ends of the probes and are disposed beneath a receptacle device positioned so as to be engageable by the probes:

removing the receptacle device from the position in which it is engageable by the probes:

and

with the conduit-stripping portions in the second locations, effecting powered axial movement of the probes with respect to the slide to engage the distal ends of the probes with the conduit-stripping portions of the slide and strip the conduits from the probes,

wherein stripping the conduits from the distal ends of the probes comprises:

providing, for each conduit-stripping portion, a key-hole opening having a first portion with a transverse size sufficient to permit the conduit to pass therethrough and a second portion with a transverse size sufficient to permit the probe to pass therethrough, but not sufficient to permit the conduit to pass therethrough;

passing the distal end of the probe with the conduit disposed thereon through the first portion of the key-hole opening;

effecting a linear translation of the slide so that the probe is in the second portion of the keyhole opening; and

withdrawing the probe from the key-hole opening, the conduit being retained by the conduit-stripping portion when the conduit is unable to pass through the second portion of the keyhole opening.

11. The method of claim 10 , wherein stripping the conduits from the distal ends of the probes comprises moving the probes in an axial direction toward the slide until the conduits disposed on the distal ends of the probes engage the conduit-stripping portions of the slide and then moving the probes in an opposite axial direction away from the slide while retaining the conduits with the conduit-stripping portions of the slide to pull the conduits from the distal ends of the probes.

12. The method of claim 10 , comprising sequentially retaining each of the conduits during axial movement of the probes away from the slide so that all conduits are not pulled from the distal ends of the probes simultaneously.

13. The method of claim 10 , wherein one or more magnets are carried on the slide such that, when the slide is in the first location, the magnets have substantially no effect on magnetically-responsive solid supports contained in a receptacle device positioned so as to be engageable by the probes, and when the slide is in the second location, the magnets are positioned adjacent to the receptacle device so that the magnets will draw at least a portion of the magnetically-responsive solid supports to a wall of the receptacle device.

14. The method of claim 13 , wherein the magnetically-responsive solids supports are adapted to immobilize an analyte thereon.