Vial and sleeve for analytical instruments

Abstract: Apparatus for use in analytical instruments such as autosamplers comprises a tapered vial and a sleeve. The sleeve includes an annular inner frustoconical portion (7) which receives the closed end of the vial to locate it in an operative position of an autosampler. The portion (7) may include a cylindrical extension for precisely defining the axial height of the vial relative to the sleeve, and hence the instrument.

Description: This invention relates to apparatus for use in analytical instruments and in particular it relates to apparatus for use in instruments such as autosamplers for supporting and retaining substances in the correct disposition with regard to cartridges on such a machine. According to the present invention there is provided a sleeve for locating in a well in an analytical machine adapted to, axially, removably receive a vial having an open end and a closed end, said vial having a tapering portion towards its closed end; characterised in that said sleeve comprises a cylindrical body portion, a skirt depending from the cylindrical portion and an internal annular lip forming a frustoconical portion, the skirt extending level to or beyond the extent of the lip and the frustoconical portion adapted to accommodate part of the tapering portion of the vial to locate the vial, the skirt being frustoconical and being of wider cross-section at its distal portion to prevent inadvertent removal of the sleeve from a well when an inserted vial is axially removed from the sleeve. The narrower end of the frustoconical portion of the sleeve may have an opening through which the closed end of the vial can protrude. Alternatively, it may be provided with a cylindrical extension having its distal end closed to define the rest portion of an inserted vial. The sleeve may include circumferential inwardly directed ribs or protrusions at selected positions along its length for locating tightly a vial. According to the present invention there is further provided apparatus for use in analytical instruments, comprising a vial having a closed end, the vial having a taper towards the closed end, and a sleeve as defined above. The vial is preferably necked. Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 shows a vial; Figure 2 shows a perspective view of a sleeve for locating the vial in an autosampler: Figure 3 shows a cross section through the longitudinal axis of Figure 2; Figure 4 shows a second sleeve embodying the invention; Figure 5 shows a cross-section through the longitudinal axis of Figure 4; and Figure 6 shows schematically the manner in which the vial is received in the sleeve. It should be noted that the drawings are not necessarily mutually to scale. Referring to Figure 1, a vial for use in sampling is typically made of a glass such as borosilicate glass. It comprises a generally cylindrical body portion 1. A tapered portion 2 leads from the body portion and terminates in a relatively narrow closed end 3. At the other end of the vial there is a neck 4 and an open collar portion 5. The neck and collar are adapted so that a cap may be crimped on to secure contents inside a vial. Alternatively, other configurations may be used, such as a screwthreaded top, in which case it need not necessarily have a reduced diameter neck. Typically, the vial has a capacity of 0.9 ml and is designed to be suitable for microsampling and other types of work. A tapered vial as described above allows maximum sample displacement and is admirably suited for microsampling work. However, lateral support is necessary for such a vial, which support may be, but is not always, provided by the wells in autosamplers. Figure 2 shows a sleeve. This is typically made to be as low cost as possible and is made of a plastics material, such as polyethylene. Alternatively materials such as PTFE may be used, or any other suitable material. It may be translucent in one embodiment. The sleeve comprises a cylindrical body 6 having an internal diameter suitable for receiving a selected vial lengthwise, and an outside diameter of size chosen to match the apertures in a cartridge of a desired autosampler. As shown more clearly in Figure 3, the sleeve includes an internal radial lip or flange 7 which is frustoconical. The cone is truncated and forms an aperture 8 towards the bottom of the sleeve, which aperture is of diameter large enough to enable all or part of the tapered portion of the vial to pass through but not to allow the main body portion of the vial to pass. The aperture serves to prevent the vial from dropping too far down the sleeve, since if it did a robot arm on an autosampler might fail to pick up the vial to transfer it to another position. The cone 7 serves to support and axially position a vial with respect to the sleeve. The angled nature of the walls of the cone also enables a vial inserted at an angle to the longitudinal axis of the sleeve to tilt and slide down into its correct position. Correct axial positioning of a vial with respect to an autosampling machine can be very important. The conical lip enables easy axial centring. The sleeve also enables the vial to be positioned in a vertical concentric position, which is necessary to ensure correct pick-up by a robot arm. Figures 2 and 3 also show an inner radial rib 9 of small depth. This rib can aid centring of a vial with respect to the sleeve and can help to safely secure a delicate vial but may be omitted in other embodiments. The top of the collar of the sleeve can also optionally have a circumferential indentation as shown which again helps to centre and support the vial. The base of an autosampler well is often not a flat surface, but has a curved or angled surface which may allow the tapered end of a vial to drop down too far with respect to the sleeve, and hence make it difficult to pick up with a robot arm. Figures 4 and 5 show an alternative embodiment of the sleeve intended to prevent this. This sleeve is similar to that of Figures 2 and 3 but includes a cylindrical downwardly directed extension 11 on the frustoconical portion 7. The cylinder is closed by a membrane 12 at its distal end, which is general coplanar with the bottom end of outer cylinder 6. In use, a vial is received in the sleeve such that its end abuts membrane 12, thus positively locating and determining the axial height of the vial. It can be important to determine the height of the vial not only so that the vial can be picked up by a robot arm but also so that the depth of needle insertion into the vial can be accurately determined. Figure 6 shows schematically how a vial may be held by a sleeve. This Figure shows how the sleeve body may flare slightly below the junction with the conical lip portion 7. The internal diameter of the wells in some autosamplers can vary quite considerably and hence the flared nature of the body can help to secure the sleeve and vial in any one of a range of sizes of wells. No internal radial ribs are shown in this example. The sleeve and vial are particularly, but not exclusively, useful when used with autosamplers such as Hewlett Packard HP 7673A and HP 1050 autosamplers, series I and II, in both the storage carousel and the central well above the injection port. The sleeve can be reusable. It can be left permanently in the sample tray holder and the turret above the injection ports of both these autosamplers, with only the sample vial being transported between the two by robot arms. The vials are transferred between their holders in the carousel to a central well which is located below the needle system.

Claims: A sleeve for locating in a well in an analytical machine adapted to, axially, removably receive a vial having an open end (5) and a closed end (3), said vial having a tapering portion (2) towards its closed end; characterised in that said sleeve comprises a cylindrical body portion (6), a skirt depending from the cylindrical portion and an internal annular lip (7) forming a frustoconical portion, the skirt extending level to or beyond the extent of the lip and the frustoconical portion adapted to accommodate part of the tapering portion of the vial to locate the vial, the skirt being frustoconical and being of wider cross-section at its distal portion to prevent inadvertent removal of the sleeve from a well when an inserted vial is axially removed from the sleeve. A sleeve as claimed in Claim 1, wherein the narrower end of the frustoconical portion has an opening (8) through which the closed end of a vial can protrude. A sleeve as claimed in Claim 1, wherein the frustoconical portion (7) has a wider end and a narrower end, and wherein a cylindrical extension (11) is provided at the narrower end of the frustoconical portion, the extension having its distal end closed to define the rest position of a vial when inserted. A sleeve as claimed in any one of the preceding claims including at least one inwardly directed annular rib (9) for locating tightly a vial. A sleeve as claimed in Claim 4, including two or more longitudinally spaced annular ribs. A sleeve as claimed in any preceding claim, wherein said sleeve is of plastics material. Apparatus for use in analytical instruments, comprising a vial having a closed end, the vial having a taper towards the closed end, and a sleeve as claimed in any one of the preceding claims. Apparatus as claimed in Claim 7, wherein the taper of the vial is outwardly concave. Apparatus as claimed in Claim 7 or Claim 8, wherein the closed end of the vial is rounded. Apparatus as claimed in any of Claims 7 to 9 wherein the vial is necked.

Inventors: BAXTER JAMES ALEXANDER, BAXTER, JAMES ALEXANDER
Applicants: CHROMACOL LTD, CHROMACOL LIMITED
Application year: 1991
Main classification: B01L9
IPC codes: B01L9, B01L3