ANALYZER FOR PERFORMING MEDICAL DIAGNOSTIC ANALYSIS

Field of the invention

The invention concerns an analyzer according to the preamble of claim 1. r - Background of the invention

U. S. Patent Specification No. 6,106,781 (Rosenberg) describes a conveying system for analytical samples. This system comprises a disk-shaped cuvette conveyor which has an array of cuvette holders located at the periphery of the cuvette conveyor and uniformly spaced along a first circle, and drive means for rotating the cuvette conveyor about a rotation axis in order to position each of the cuvettes carried by the cuvette conveyor at an angular position.

This conveyor comprises 99 cuvette holders. This number limits the number of samples that can be analyzed by the analyzer per unit of time. The analyzer is preferably used for clinical chemistry tests only, because for immunoassays the maximum number of samples that can be analyzed by the analyzer per unit of time would be even lower. Immunoassays require indeed different dilution steps and/or incubation times, compared to clinical chemistry assays.

An object of the invention is to overcome the above mentioned limitation so that a higher number of samples can be analyzed by the analyzer per unit of time. Summary of the invention

According to the invention the above aim is achieved by means of an analyzer defined by claim 1, comprising at least two disc-shaped cuvette conveyors. Claims 2 to 16 define preferred embodiments of this analyzer. Within the context of the instant invention the cuvettes are containers for holding samples and/or mixing samples with reagents. According to a preferred embodiment cuvettes are

adapted to allow optical detection of the liquid contained therein directly through the cuvette walls.

The present invention makes it possible to achieve a higher number of samples analyzed per unit of time and/or to perform clinical chemistry tests as well as immunoassays using one and the same analyzer. Moreover, due to the fact that the at least two cuvette conveyors can operate synergistically, e.g. by exchanging cuvettes and/or delegating assay steps to the other while one is busy with other operations, or when failure in one occurs, time, costs and space can be saved if compared to e.g. two analyzers each carrying only one cuvette conveyor.

Brief description of the drawings

The subject invention will now be described in terms of its preferred embodiments with reference to the accompanying drawings. These embodiments are set forth to aid the understanding of the invention, but are not to be construed as limiting.

Fig. 1 shows a first perspective view of some components of an analyzer according to the invention.

Fig. 2 shows a perspective view of some components of an analyzer according to the invention similar to Fig. 1 comprising a housing of this analyzer open from the top.

Fig. 3 shows a top plan view of some components of an analyzer according to the invention as represented in Fig. 1.

Fig. 4 shows a cross-sectional view taken along a plane A-A in Fig.3.

Fig. 5 shows a cross-sectional view taken along a plane B-B in Fig.3.

Fig. 6 shows a top plan view of some components of an analyzer according to the invention as represented in Fig.l.

Fig. 7 shows a cross-sectional view taken along planes D-D represented in Fig.6.

Fig. 8 shows a first perspective view of workstation 14 represented in Fig. 1. Fig. 9 shows a second perspective view of workstation 14 represented in Fig. 1.

Fig. 10 shows a third perspective view of workstation 14 represented in Fig. 1.

Fig. 11 shows a second perspective view of the analyzer represented in Fig. 1.

Fig. 12 shows a third perspective view of the analyzer represented in Fig. 1.

Fig. 13 shows a top plan view of some components of an analyzer according to the invention as represented in Fig. 1 without the rotatable conveyors 11 and 12, but showing the conveyor drives 24 and 25.

Fig. 14 shows a cross-sectional view of conveyor drive 24 represented in Fig. 13 taken along plane E-E in Fig. 13.

Fig. 15 shows a cross-sectional view of conveyor drive 25 represented in Fig. 13 taken along plane F-F in Fig. 14.

Fig. 16 shows a top plan view of the analyzer according to the invention as represented in Fig. 1 and including work stations suitable for performing immunoassays.

Fig. 17 shows a perspective view of workstation 28 (WSG) represented in Fig. 16.

Fig. 18 shows a first perspective view of workstation 22 (WSK) represented in Fig. 16.

Fig. 19 shows a second perspective view of workstation 22 (WSK) represented in Fig. 16.

Fig. 20 shows a top view of workstation 22 (WSK) represented in Fig.16.

Fig. 21 shows a cross-sectional view of workstation 22 (WSK) taken along plane G-G in Fig. 20. Fig. 22 shows a perspective view of workstation 23 (WSL) represented in Fig. 16.

Fig. 23 shows a top view of workstation 23 (WSL) represented in Fig. 16.

Fig. 24 shows a cross-sectional view of workstation 23 (WSL) represented in Fig. 16 taken along plane H-H in Fig.23.

Fig. 25 shows a perspective view of a cuvette 31.

Fig. 26 shows a first side view of cuvette 31 shown by Fig.25. Fig. 27 shows a second side view of cuvette 31 shown by Fig.25.

Fig. 28 shows a partial perspective view of workstation 1 (WSA) and conveyors 11 and 12 shown in Fig. 1.

Fig. 29 shows a partial perspective view of workstation 1 (WSA), drop-off station 10 and conveyors 11 and 12 in Fig. 1.

Fig. 30 shows a partial perspective view of fluorescence polarization photometer 2 and conveyors 11 and 12 shown in Fig. 1.

Fig. 31 shows a partial perspective view of workstation 3 (WSE) and conveyor 12shown in Fig. 1.

Fig. 32 shows a partial perspective view of workstation 5 (WSB) and conveyors 11 and 12 shown in Fig. 1.

Fig. 33 shows a partial perspective view of workstation 6 (WS2) and conveyors 11 and 12 shown in Fig. 1.

Fig. 34 shows a partial perspective view of workstation 7 (WSCl) and conveyors 11 and 12 shown in Fig. 1. Fig. 35 shows a partial perspective view of workstation 7 (WSC2) and conveyor 11 shown in Fig. 1.

Fig. 36 shows a partial perspective view of absorptions photometer 9 and conveyors 11 and 12 shown in Fig. 1.

Fig. 37 shows a first partial perspective view of workstation 14 (WSF) and conveyors 11 and 12 shown in Fig. 1.

Fig. 38 shows a second partial perspective view of workstation 14 (WSF) shown in Fig. 16 and of conveyors 11 and 12 shown in Fig. 1. Fig. 39 shows a partial perspective view of workstation 22 (WSK) and conveyor 11 shown in Fig. 16.

Fig. 40 shows a partial perspective view of workstation 26 (WSI 1) shown in Fig. 16 and of conveyors 11 and 12 shown in Fig. 1. Fig. 41 shows a partial perspective view of workstation 27 (WSI 2) shown in Fig. 16 and of conveyors 11 and 12 shown in Fig. 1.

Fig. 42 shows a first partial perspective view of workstation 28 (WSG) shown in Fig. 16 and of conveyors 11 and 12 shown in Fig. 1.

Fig. 43 shows a second partial perspective view of workstation 28 (WSG) shown in Fig. 16 and of conveyors 11 and 12 shown in Fig. 1.

Fig. 44 shows a partial perspective view of workstation 29 (WSH) shown in Fig. 16 and of conveyors 11 and 12 shown in Fig. 1.

Reference numerals used in drawings

1 workstation WSA

2 fluorescence polarization photometer

3 workstation WSE 4 cuvette conveyor

5 workstation WSB

6 workstation WS2

7 workstation WSCl

8 workstation WSC2 9 absorption photometer

10 first waste drop-off station

11 second cuvette conveyor / upper cuvette conveyor

12 first cuvette conveyor / lower cuvette conveyor

13 second waste drop-off station 14 workstation WSF

15 analyzer housing without cover part thereof

16 opening for pipetting reagents at workstation 5 (WSB)

17 opening for pipetting reagents at workstation 6 (WS2)

18 opening for pipetting samples at workstation 7 (WSCl) 19 opening for pipetting samples at workstation 8 (WSC2)

20 fan

21 heating element

22 workstation WSK

23 workstation WSL 24 conveyor drive for first cuvette conveyor 12

25 conveyor drive for second cuvette conveyor 11

26 workstation WSI 1

27 workstation WSI 2

28 workstation WSG 29 workstation WSH

31 reaction cuvette

32 body of cuvette 31

33 lower end portion of cuvette 31

34 upper end portion of cuvette 31 35 bottom wall of cuvette 31

36 opening of cuvette 31

37 tongue

38 tongue

39 length symmetry axis of cuvette 31 40 pipetting head

41 pipetting needle

42 control unit

43 rotation axis

44 pipetting position in working station 14 (WSF) 45 pipetting position in working station 28 (WSG)

46 pipetting position in working station 29 (WSH)

47 planar side wall of the cuvette 31

48 planar side wall of the cuvette 31

Detailed description of the invention

Preferred embodiments of the invention are described hereinafter with reference to the accompanying drawings.

EXAMPLES

EXAMPLE 1:

FIRST EMBODIMENT OF AN ANALYZER

Fig. 1 shows an analyzer for performing medical diagnostic analysis of biological samples comprising the following components: a first disk-shaped cuvette conveyor 12, and first drive means 24 (not shown in Fig. 1, but shown in Fig. 14) for rotating the first cuvette conveyor 12 about a rotation axis 43 (represented in Fig. 4) . Rotation axis 43 passes through the center of cuvette conveyor 12 and extends in vertical direction, e.g. in Z-direction in Fig. 1.

Cuvette conveyor 12 is arranged parallel to a horizontal plane, e.g. an X-Y-plane in Fig. 1, and has a first array of cuvette holding positions, hereinafter called cuvette holders, spaced along a first circle the center of which lies on rotation axis 43.

First drive means 24 rotate cuvette conveyor 12 about the vertical rotation axis 43 in order to position cuvettes 31 carried by the first cuvette conveyor at a first angular position. The analyzer shown by Fig. 1 further comprises: at least a second disk-shaped cuvette conveyor 11, and at least second drive means 25 (not shown in Fig. 1, but shown by Fig. 15) for rotating the at least second cuvette conveyor 11 about vertical rotation axis 43 in order to position cuvettes 31 carried by the at least second cuvette conveyor 11 at a second angular position. The operation of the at least second drive means 25 is independent from the operation of the first drive means 24.

Cuvette conveyor 11 is also arranged parallel to a horizontal plane, e.g. an X-Y-plane in Fig. 1, and has a second array of cuvette holders spaced along a second circle the center of which also lies on rotation axis 43.

The cuvette holders of the first cuvette conveyor 12 and the cuvette holders of the at least second cuvette conveyor 11 are adapted for holding cuvettes 31 which preferably have the same shape and dimensions.

The centers of the first circle and of the second circle lie on a vertical axis which is a common rotation axis 43 of the first cuvette conveyor 12 and the at least second cuvette conveyor 11.

The first cuvette conveyor 12 and the at least second cuvette conveyor 11 are rotatable around their common rotation axis 43.

The first cuvette conveyor 12 and the at least second cuvette conveyor 11 are spaced from each other in axial direction along the rotation axis' 43 with an air gap between the first cuvette conveyor 12 and the at least second cuvette conveyor 11.

The analyzer shown by Fig. 1 further comprises a workstation 1 (WSA) , a fluorescence polarization photometer 2, a workstation 3 (WSE) , a workstation 5 (WSB) , a workstation 6 (WS2), a workstation 7 (WSCl), a workstation 8 (WSC2), absorption photometer 9, a first waste drop-off station 10, an automatic pipetting unit 40 and a control unit 42.

The analyzer shown by Fig. 1 preferably comprises a second waste drop-off station 13.

Workstation 1 (WSA) transports a cuvette and positions it in a cuvette holder of conveyor 12 and after termination of the processing of the cuvette removes it from conveyor 12 and brings it to a waste drop-off station 10 which delivers the cuvette to a waste container.

Fluorescence polarization photometer 2 measures the content of a liquid, e.g. comprising a blood sample, contained in a cuvette .

Workstation 3 (WSE) takes a selected cuvette containing a liquid comprising a sample, e.g. a blood sample, from conveyor 12, transports it to fluorescence polarization photometer 2, and brings the cuvette back to a cuvette holder of conveyor 12.

Workstation 5 (WSB) takes a selected cuvette containing a liquid from conveyor 12, brings it to a reagent pipetting position 16 where a first reagent is pipetted into the cuvette, agitates the cuvette for effective mixing of the liquids in the cuvette, and after this mixing step brings the cuvette back to a cuvette holder of conveyor 12.

Workstation 6 (WS2) takes a selected cuvette containing a liquid from conveyor 12, brings it to a reagent pipetting position 17 where a second reagent is pipetted into the cuvette, agitates the cuvette for effective mixing of the liquids in the cuvette, and after this mixing step brings the cuvette back to a cuvette holder of conveyor 12.

Workstation 7 (WSCl) takes a selected cuvette containing a liquid from conveyor 12, brings it to a reagent pipetting position 18 where a liquid, e.g. sample, reagent or a dilution liquid is pipetted into the cuvette, agitates the cuvette for effective mixing of the liquids in the cuvette, and after this mixing step brings the cuvette back to a cuvette holder of conveyor 12.

Workstation 8 (WSC2) takes a selected cuvette containing a liquid from conveyor 12, brings it to a reagent pipetting position 19 where a liquid, e.g. sample, reagent or a dilution liquid is pipetted into the cuvette, agitates the cuvette for effective mixing of the liquids in the cuvette, and after this mixing step brings the cuvette back to a cuvette holder of conveyor 12. In another embodiment of the analyzer shown by Fig. 1,

Workstation 7 (WSCl) takes a selected cuvette containing a liquid from conveyor 11, brings it to a reagent pipetting position 18 where a liquid, e.g. sample, reagent or a dilution liquid is pipetted into the cuvette, agitates the cuvette for effective mixing of the liquids in the cuvette, and after this mixing step brings the cuvette back to a cuvette holder of conveyor 11.

Absorption photometer 9 measures the content of a liquid, e.g. comprising a blood sample, contained in a cuvette. The cuvette holders of the first cuvette conveyor 12 and the cuvette holders of the at least second cuvette conveyor 11 are adapted for holding cuvettes 31 having an inner volume in a range going from 0.2 to 3 milliliter.

As shown by Fig. 2, a preferred embodiment of the analyzer shown by Fig. 1 further comprises a housing 15 the interior of which defines a chamber. This chamber has an upper opening which is closed by a removable cover (not shown) during operation of the analyzer. That opening allows access to the components contained therein.

During operation of the analyzer and with the above mentioned chamber closed by the above mentioned cover, air temperature within the chamber is regulated and maintained at a determined value by means of a temperature regulation arrangement which includes a fan 20 and a heating element 21 shown by Fig. 7. In Fig. 7 the air flow generated by fan 20 is represented by arrows. The first cuvette conveyor 12 and the at least second cuvette conveyor 11 are located within the above mentioned chamber of housing 15 and are thereby kept at the same temperature.

As shown by Figures 1, 4 and 5, a preferred embodiment of the analyzer shown by Fig. 1 further comprises a first cuvette transport device 14 (WSF) , which is located close to the periphery of the first cuvette conveyor 12, respectively the at least second cuvette conveyor 11, and which is adapted for transporting a cuvette 31 from one of the cuvette holders of the first cuvette conveyor 12 to one of the cuvette holders of the at least second cuvette conveyor 11 and/or vice versa. Figures 8, 9 and 10 show different perspective views of workstation 14 (WSF) .

Preferred embodiments of the analyzer shown by Fig. 1 further comprise a plurality of workstations arranged around and close to the periphery of the first cuvette conveyor 12 and the at least second cuvette conveyor 11. Those workstations comprise cuvette transport means for removing a cuvette 31 from one of the cuvette holders of the first cuvette conveyor or of the at least second cuvette conveyor 11, for transporting the cuvette to a processing position, and for transporting the cuvette from the processing position to another one of the cuvette holders of the first cuvette conveyor 12 or of the at least second cuvette conveyor 11, or for transferring said cuvette 31 to a cuvette ejection device, e.g. waste drop-off station 10 or 13.

The automatic pipetting unit of the analyzer shown by Fig. 1 comprises a pipetting head 40 which transports a pipetting

needle 41 in three orthogonal directions X, Y and Z for performing pipetting operations, e.g. for pipetting a sample or a reagent aliquot into a selected cuvette 31 at a selected processing position at a selected point of time. The location of the processing position is associated with the position of one of the plurality of workstations.

The control unit 42 of the analyzer shown by Fig. 1 controls the operation of the first drive means 24, of the at least second drive means 25, of the first cuvette transport device 14 (WSF) , of the plurality of workstations, of the automatic pipetting unit, and of the photometers 2 and 9. During operation of the analyzer, the control unit 42 continuously receives and stores the current position of each cuvette, wherein the cuvettes 31 have a variable position. The control unit 42 controls the processing of each sample contained in one of the cuvettes 31 according to predetermined specific sequence of method steps for the treatment of that sample.

The control unit 42 optimizes the execution of the sequences of method steps for processing the samples contained in all the cuvettes 31 and thereby maximizes the number of samples analyzed per unit of time.

In a preferred embodiment, the at least second cuvette conveyor 11 has the same shape and dimensions as the first cuvette conveyor 12.

In a preferred embodiment, each of the cuvette holders has a recess for receiving a tongue 37, 38 which is an integral portion of a cuvette 31. That recess extends in radial direction and the tongue 37, 38 is insertable in the recess in radial direction.

In a preferred embodiment, the first drive means 24 and the at least second drive means 25 are each adapted for rotating the first cuvette conveyor 12 respectively the at least

second cuvette conveyor 11 in a first sense and/or in a second sense opposite to the first sense.

In a preferred embodiment, the first cuvette transport device 14 (WSF) is further adapted for removing a cuvette 31 from one of the cuvette holders of the at least second cuvette conveyor 11 and for transferring the cuvette 31 to a cuvette ejection device, e.g. waste drop-off station 13.

In a preferred embodiment, the first cuvette transport device 14 (WSF) is further adapted for transferring the cuvette 31 from one of the cuvette holders of the at least second cuvette conveyor 11 to a processing position, e.g. a pipetting position 44, and from the processing position back to the cuvette holder, or to a cuvette ejection position in waste drop-off station 13 which delivers the cuvette to a waste container.

In a preferred embodiment, the analyzer further comprises a second cuvette transport device 1 (WSA) for automatically loading empty cuvettes 31 onto the first cuvette conveyor 12, by inserting each cuvette 31 into a cuvette holder of the first cuvette conveyor 12.

In a preferred embodiment, the second cuvette transport device 1 (WSA) is also adapted for removing a cuvette 31 from one of the cuvette holders of the first cuvette conveyor 12 and for transferring the cuvette 31 to a cuvette ejection device, e.g. waste drop-off station 10.

In a preferred embodiment, the second cuvette transport device 1 (WSA) is also adapted for removing a cuvette 31 from one of the cuvette holders of the at least second cuvette conveyor 12 and for transferring the cuvette 31 to a cuvette ejection device, e.g. waste drop-off station 10 or 13.

In a preferred embodiment, the analyzer further comprises a third cuvette transport device 1 (WSA) for automatically loading empty cuvettes 31 onto the at least second cuvette

conveyor 11, by inserting each cuvette 31 into a cuvette holder of the at least second cuvette conveyor 11.

In a preferred embodiment shown by Fig. 3, a plurality of workstations are arranged around the second cuvette conveyor 12 and this plurality of workstations comprises a workstation, e.g. workstation 5 (WSB), 6 (WS2), 7 (WSCl) and/or 8 (WSC2), which are adapted for removing a cuvette 31 from a cuvette holder of the at least second cuvette conveyor 12, and for transporting the cuvette 31 to a processing position 16, 17, 18, 19 and from that processing position back to a cuvette holder of the at least second cuvette conveyor 12. As shown by Fig. 3, processing positions are defined e.g. by pipetting openings 16, 17, 18, 19 of work stations 5, 6, 7, 8 respectively. EXAMPLE 2:

SECOND EMBODIMENT OF AN ANALYZER

A second embodiment of an analyzer according to the invention is shown by Fig. 16. This second embodiment comprises the above mentioned components of the analyzer described above as Example 1 and the plurality of workstations arranged around the cuvette conveyors comprises: a workstation 22 (WSK) shown also by Figures 19 20, 21 and 22, workstation 26 (WSI 1), optionally a workstation 27 (WSI 2) which has the same structure and function as workstation 26 (WSI 1), workstation 28 (WSG) shown also by Fig. 17, a workstation 29 (WSH), and a workstation 23 (WSL) shown also by Figures 23, 24 and 25.

In Fig. 16, the reference numbers 44, 45 and 46 designate a pipetting position in workstation 14 (WSF) , workstation 28 (WSG) , and workstation 29 (WSH) respectively.

Workstation 22 (WSK) is adapted for taking out liquid from a cuvette 31 and/or adding liquid to a cuvette 31, wherein cuvette 31 is preferably held by workstation 26 (WSI 1) . Workstation 26 (WSI 1) is adapted for removing a cuvette 31 from a cuvette holder of the at least second cuvette

conveyor 11, for mixing the liquid in the cuvette, and for inserting the cuvette 31 into one of the cuvette holders of the at least second cuvette conveyor 11.

Workstation 28 (WSG) is adapted for removing a cuvette 31 from a cuvette holder of the at least second cuvette conveyor 11, for transporting the cuvette 31 to a reagent pipetting position 45, for mixing the liquid in the cuvette 31, and for transporting the cuvette 31 from that pipetting position to one of the cuvette holders of the at least second cuvette conveyor 11.

Workstation 29 (WSH) is adapted for removing a cuvette 31 from a cuvette holder of the at least second cuvette conveyor 11, for transporting the cuvette 31 to a sample pipetting position 46, for mixing the liquid in the cuvette 31, and for transporting the cuvette 31 from that pipetting position back to one of the cuvette holders of the at least second cuvette conveyor 11.

Workstation 23 (WSL) is a washing station which serves for cleaning the pipetting needle 41 and which provides cleaning liquids for rinsing a measuring station.

In preferred embodiments of the analyzers according to Example 1 and Example 2, absorption photometer 9 photometrically measures the contents of a cuvette 31 held by one of the cuvette holders. In preferred embodiments of the analyzers according to Example 1 and Example 2, the analyzer comprises a fourth cuvette transport device 3 (WSE) for removing a cuvette 31 containing a sample-reagent-mixture from a cuvette holder, for holding the cuvette 31 at a measurement position for the fluorescence polarization photometer 2, and for inserting the cuvette 31 into one of the cuvette holders or for transferring said cuvette 31 to a cuvette ejection device, , e.g. waste drop-off station 10, after a measurement of the cuvette contents in the fluorescence polarization photometer 2.

In preferred embodiments of the analyzers according to Example 1 and Example 2, the analyzer further comprises a plurality of reaction cuvettes 31 of the type illustrated by Figures 25, 26 and 27. Each cuvette 31 is insertable into one of the cuvette holders of the cuvette conveyors 11 and 12. Cuvette 31 has a tubular body 32 which has a longitudinal axis 39 and two opposite ends along said longitudinal axis. The tubular body 32 has an upper opening 36, a bottom wall 35, planar side walls 47, 48 opposing each other through which optical detection is carried out, and tongues 37, 38 which are adjacent to the upper opening 36 and which extend in opposite directions along a plane normal to the longitudinal axis 39. Each of the tongues 37, 38 is insertable in one of the cuvette holders of the cuvette conveyors 11 and 12. Planar side walls 47, 48 are preferably plane-parallel side walls which are parallel to each other.

Figures 28 to 44 illustrate the cooperation of the various workstations with the cuvette conveyors 11 and 12 and with the photometers 2 and 9.

Fig. 28 shows workstation 1 (WSA) as a gripper thereof takes a cuvette 31 from a cuvette holder of conveyor 12.

Fig. 29 shows workstation 1 (WSA) as a gripper thereof delivers a cuvette 31 to drop-off station 10.

Fig. 30 shows a fluorescence polarization photometer 2 and a cuvette 31 positioned to be measured therewith.

Fig. 31 shows workstation 3 (WSE) which serves for taking a cuvette 31 from conveyor 12 and bringing it to a measurement position where the cuvette contents is measured by fluorescence polarization photometer 2. Fig. 32 shows workstation 5 (WSB) as a gripper thereof takes a cuvette 31 from a cuvette holder of conveyor 12.

Fig. 33 shows workstation 6 (WS2) as a gripper thereof takes a cuvette 31 from a cuvette holder of conveyor 12.

Fig. 34 shows workstation 7 (WSCl) as a gripper thereof takes a cuvette 31 from a cuvette holder of conveyor 11.

Fig. 35 shows workstation 8 (WSC2) as a gripper thereof takes a cuvette 31 from a cuvette holder of conveyor 11.

Fig. 36 shows absorptions photometer 9 as it measures the contents of one of the cuvettes 31 held by conveyor 12 as the cuvette passes in front of photometer 9 during rotation of conveyor 12.

Fig. 37 shows workstation 14 (WSF) as a gripper thereof takes a cuvette 31 from a cuvette holder of conveyor 12.

Fig. 38 shows workstation 14 (WSF) as a gripper thereof delivers a cuvette 31 to drop-off station 13.

Fig. 39 shows workstation 22 (WSK) effecting a pipetting operation on a cuvette 31 positioned in workstation 26 (WSI 1) .

Fig. 40 shows workstation 26 (WSI 1) holding a cuvette 31 removed by workstation 26 (WSI 1) from a cuvette holder of cuvette conveyor 11.

Fig. 41 shows workstation 27 (WSI 2) holding a cuvette 31 removed by workstation 26 (WSI 2) from a cuvette holder of cuvette conveyor 11.

Fig. 42 shows workstation 28 (WSG) holding a cuvette 31 being removed from or inserted into a cuvette holder of cuvette conveyor 11. Fig. 43 shows workstation 28 (WSG) holding a cuvette 31 ready for a pipetting operation to be effected on that cuvette .

Fig. 44 shows workstation 29 (WSH) holding a cuvette 31 removed by workstation 29 (WSH) from a cuvette holder of cuvette conveyor 11.