Cuvette matrix

Abstract: The invention relates to a cuvette matrix, comprising a row, from which it is possible to detach one cuvette to be placed in a stand. On the outer surface of the cuvette, at an angle from the longitudinal direction of the row of cuvettes, there is a holder member (10), which facilitates the cuvette to adhere to the sides of an opening, after when the cuvette is turned in the opening.

Description: The invention relates to laboratory technology and concerns a cuvette matrix which can be used e.g. in diagnostic assay methods. For example in diagnostic assay methods sets of cuvettes comprising of one or more rows of cuvettes are commonly in use. Standard-sized 8*12 microtitration plates and their partial matrices are especially common. Also such cuvette sets are used, in which the cuvettes have been detachably joined to each other. In this way, just a required number of cuvettes can be used at a time in each case. Such a cuvette set provided with breakable stems is known for example from the patent application publication FI-A-894025 (corresponding to EP-A-0 415 307). The cuvette set is connected with a stand which has square holes corresponding to the cuvettes and in each of them resilient holder means for keeping the cuvettes in place. Each cuvette has a shoulder abutting on the upper surface of the walls of the square holes. When single cuvettes detached from the matrix described above are used, a cuvette does not always stay sufficiently satisfactorily stationary in the stand. The main object of this invention is to provide a cuvette matrix in which a single cuvette removed therefrom stays better than the known cuvettes in position in the stand. The most essential feature of the invention is the fact that on the outer surface of the cuvette, beneath the shoulder and at an angle relative to the longitudinal direction of the cuvette row, there is a holder member, which together with the walls of the cuvette opening of the stand keeps the cuvette tightly in position after it has been turned in the opening. The invention and its some preferred embodiments are defined in detail in the patent claims. The cuvette matrix in accordance with the invention comprises one or more cuvette rows, in which the cuvettes are connected to one another such that when desired, it is possible to detach one or more cuvettes to be used at a time. The cuvette matrix is preferably prepared from some plastic, such as polystyrene suitable for the purpose. For optical measurements, the bottom of the cuvette is made transparent, when so needed. The cuvettes are especially suitable for use in various diagnostic assays to be made with fluid samples. When required, the cuvettes can be pretreated, e.g., by coating with an antigen of an antibody to be determined. The cuvettes are meant to be placed in a specific stand which has an opening for each cuvette. The cuvettes stay in the opening by means of friction. The opening is preferably a square by shape, but it may also have another shape, such as a hexagon. The stand with its cuvettes can then be brought for measurement e.g. into a vertical measurement photometer. The cuvette preferably is by its outer surface slightly downwardly tapering, whereby its positioning in the stand is easier. On the outer surface there may also be a shoulder or the like which facilitates the positioning of the cuvette at a certain height relative to the stand. Each cuvette has on its outer surface a holder member, which, when the cuvette is turned, fixes the cuvette even more rigidly to the opening. Preferably the holder member is essentially at an angle of 45° from the longitudinal direction of the row of cuvettes, whereby the cuvette is correspondingly turned essentially by 45°. Preferably there are two holder members on the opposite sides of the cuvette. Preferably the holder member is an extension on the surface of the cuvette. The extension preferentially comprises a vertical plane, which, when the cuvette is turned, steadily positions against the vertical wall of the opening of the stand. The extension may also be e.g. a nodule or a ridge of some kind, whereby the wall of the opening may have a notch or groove corresponding thereto. Preferably the opening of the stand further has also resilient pressing members, which keep the cuvette in position. In the following, an embodiment of the invention is described as an example. In the drawings of the description: Fig. 1 shows a side view section along the longitudinal axis of the cuvette matrix; Fig. 2 shows the same matrix seen from above; Fig. 3 shows a side view section of a single cuvette; Fig. 4 shows the same cuvette sectioned horizontally along the lines A-A; and Fig. 5 shows a stand for cuvette matrices seen from above. The cuvette matrix of the figures, and its stand are by their principal solution similar to those described in the EP-A-415 307. In the cuvette matrix 1, the cuvettes 2 are connected to each other such that a desired number of cuvettes can be detached from the matrix by folding the stem 3 between the cuvettes. The cuvettes are circular by their cross-section and slightly narrower by their lower part. The entire matrix or a part thereof can be placed in a stand 4, which has 8*12 holes 5 with square cross-section. The side of the hole is slightly broader than the diameter of the bottom of the cuvette. The cuvettes can thus be positioned into the holes of the stand. However, the side of the hole is slightly narrower than the cuvette diameter above the bottom. The cuvette thus is fixed to the hole by means of friction. For facilitating folding, the stem 3 has been narrowed. In the solution of the figure, there is a narrowing at each end, but also e.g. one narrowing may be made in the center, whereby the stem always breaks symmetrically. The holes 5 form eight horizontal rows marked with letters (A-H) and twelve vertical columns marked with numerals (1-12). The holes are bounded by a rectangular frame and its intermediate walls. The intermediate walls 6 parallel with the vertical columns are stiff and continuous. Also, every second intermediate wall 7 of the horizontal rows is continuous and stiff. Starting from the first intermediate wall 7 from the edge, parallel with the horizontal rows, every second intermediate wall parallel with the rows has been cut off at the central line of the vertical column vertically, but obliquely relative to the intermediate wall and such that a small gap is formed between the broken ends. The fingers 8 thus formed parallel with the intermediate walls slightly bend on a horizontal plane. The intermediate walls are at the fingers slightly thicker. One corner of the stand 4 is chamfered, which facilitates the identification of the correct position of the stand e.g. automatically in analyzer devices. The upper surface of the intermediate walls 6 and 7 and an extension on the inner edge of the frame abut on a shoulder 9 on the outer surface of the cuvette. In this way, the cuvettes always position at the same height on the stand. In each cuvette 2, there is at an angle of 45° from the longitudinal direction of the cuvette row on opposite sides beneath the shoulder 9 a vertical planar extension 10. When a row formed by two or more cuvettes is placed in the stand, 3, the extensions position on the corners of the holes 5. An unbroken cuvette row always stays well in position due to a friction caused by possible bending, and to the so-called "desk-drawer effect". When a single separate cuvette is used, it is turned in the hole of the stand such that the extensions 10 position against the walls of the hole. In this case, the fingers 8 press the cuvette harder and the cuvette stays well stationary.

Claims: A cuvette matrix (1) comprising at least one cuvette row formed by two or more interconnected cuvettes (2), from which row a single cuvette can be detached to be placed in a stand (4) having an opening (5) for the cuvette (2), the cuvette (2) having a shoulder (9) on its outer surface abutting on an upper surface of the walls of the opening (5), characterized in that the cuvette, on its outer surface beneath the shoulder (9), has at least one holder member (10) arranged at an angle relative to the longitudinal direction of the cuvette row, to facilitate fixing of the cuvette (2) in the opening (5) after the cuvette has been detached from the cuvette row and has been turned in the opening. The cuvette matrix according to claim 1, characterized in that the holder member (10) is arranged at an angle of essentially 45° relative to the longitudinal direction of the cuvette row. The cuvette matrix according to claim 1 or 2, characterized in that the holder member (10) is an extension of the outer surface of the cuvette having a vertically planar surface. The cuvette matrix according to any one of claims 1 to 3, characterized in that there are two holder members (10) positioned on opposite sides of the cuvette (2). The cuvette matrix according to claims 1 or 2, characterized in that the holder member (10) is in the form of a nodule or a ridge, and that the side wall of the opening has a nodge or groove corresponding to said nodule or ridge.

Inventors: JAERVIMEKI KARI, JAERVIMEKI,KARI, Järvimeki,Kari
Applicants: LABSYSTEMS OY
Application year: 1993
Main classification: B01L3
IPC codes: B01L3, G01N35, G01N1, B01L9, G01N33, G01N21