A fluorimeter sampling apparatus useful in a fluorimeter includes a linearly movable sample carrier having a plurality of cuvette holders associated therewith. Each cuvette holder, when positioned in a measuring position, is aligned with an excitation radiation entrance aperture and a fluorescence radiation exit aperture. The cuvette holders are diagonally aligned with the direction of movement of the carrier.

BACKGROUND OF THE INVENTION 
The present invention generally relates to an apparatus useful for 
presenting samples to the exitation radiation of a fluorimeter and, in 
particular, relates to an apparatus including a linearly movable carrier. 
Conventionally, a fluorimeter sampling apparatus includes a turntable 
having cuvette receptacles arranged on a circular line near the periphery 
thereof. To present samples, the turntable is rotated about its axis 
within a sample housing whereby the sample-containing cuvettes in the 
cuvette receptacles are individually and successively positioned in a 
measuring position. In this arrangement, the exitation radiation enters 
the housing along a radius of the turntable into the cuvette in the 
measuring position. The resultant fluorescence radiation exits in a 
direction normal with respect to the exitation radiation and is 
subsequently measured by a fluorimeter positioned external to the housing. 
However, the above-described apparatus includes an inherent limitation on 
the number of samples which can be included on a single turntable. This 
limitation is significant as the number of samples to be measured 
increases, for example, in fluorescence-immuno assays, the processing of 
large numbers of samples is commonplace. The turntable apparatus is 
unsuited for such large numbers of samples since, if the radius is 
enlarged to accommodate more samples, the entire apparatus, including the 
housing, becomes quite bulky. Further, there is a practical limit to the 
number of samples usable on a given turntable due to the required 
geometrical arrangement of the optical paths within the housing. 
SUMMARY OF THE INVENTION 
Accordingly, it is one object of the present invention to provide a 
fluorimeter sampling apparatus that is adapted for the serial 
investigation of a large number of samples. 
This object is achieved, at least in part, by means of a linearly movable 
carrier, which carrier includes a cuvette holder releasably attached 
thereto. In one embodiment, the cuvette holder comprises a generally 
rectangular base plate with a plurality of cuvettes arranged diagonally 
with respect to the longitudinal axis of the base plate and with retaining 
means for connecting the base plate to the carrier. 
Such a linear arrangement of the cuvettes in the direction of the carrier 
displacement permits a relatively large number of cuvettes to be 
successively and individually positioned in the measuring position without 
blocking the path of the relevant light rays. The adaptation of the 
carrier to linear displacement makes the apparatus particularly suitable 
for automation. 
Other objects and advantages will become apparent from the following 
detailed description and the accompanying drawings

DETAILED DESCRIPTION OF THE INVENTION 
An apparatus, indicated generally at 10 in the drawing, embodying the 
principles of the present invention, includes a sample housing 12, shown 
in FIG. 2, having a linearly movable sample carrier 14 therein. The 
housing 12, which is preferably rectangular, is at least equal in length 
to the sum of the length of a cuvette holder and the length of its maximum 
displacement. 
The linearly movable sample carrier 14 includes a support plate 16 
preferably guided on a pair of parallel rails 18 which rails 18 constitute 
guiding means. The guiding means can be, for example, rollers or other 
known mechanisms. The support plate 16 is provided with a means 20 for 
retaining a cuvette holder 22. In the preferred embodiment, the retaining 
means 20 is a pair of diagonally opposed apertures 24. 
The apparatus 10 also includes a support plate advancing mechanism 26 
including a leg 28 of a bracket 30 attached with two bentover lugs 32 to 
one long side of support plate 16 by means of screws 34. The other leg 36 
of bracket 30 is attached to a cylindrical rod 38. The cylindrical rod 38 
forms part of an advancing means and extends through an aperture 40 in leg 
36 and is retained on one side thereof by a washer 42 secured by a snap 
ring 44 and on another side thereof by a washer secured by a spring 46 
supported at a spring collar 48 at the cylindrical rod 38. The housing 12 
further includes two blocks 50, 52 projecting from the bottom thereof and 
having apertures through which the cylindrical rod 38 is guided. The first 
block 50 is located close to the narrow side of the housing 12, through 
which side the cylindrical rod 38 is light-tightly passed in conventional 
manner. 
The second block 52 is located at a distance therefrom beyond the center of 
the housing 12 and includes an aperture 54 aligned to the aperture in 
block 50 having a bore extending normally thereto which is closed by an 
adjusting screw 56. Preferably, a spring-loaded ball is positioned in the 
bore for purposes described hereinbelow. 
The cylindrical rod 38 is provided with annular grooves 58 formed at the 
free end thereof projecting from block 52, the distance of the grooves 58 
correspond to the distance of the cuvettes in the cuvette holder 22. The 
displacement of cylindrical rod 38 is preferably limited, on one end, by 
the abutment of snap ring 44 to the second block 52 and, on the other end, 
by the abutment of spring collar 48 to the first block 50. The end of 
cylindrical rod 38 outside of the housing 12 is provided with a knob 60 by 
means of which the cylindrical rod 38 can be manually displaced in the 
longitudinal direction of the housing 12. Alternatively, a motorized 
advancing means can be provided, for example, a rack driven by a pinion or 
a band guided and driven by rollers connected to leg 36 of bracket 30, 
with suitable locking means, sensors for the angle of rotation etc. being 
provided to limit the advance to the respectively desired amount. 
Referring particularly to FIG. 2, there is shown a first embodiment of a 
cuvette holder 22 for retaining a plurality of samples. A wall 62, forming 
part of the cuvette housing 12, includes an entrance window 64 through 
which passes the excitation radiation and an exit window 66 through which 
passes the fluorescence radiation. Preferably, the cuvette holder 22 
includes a rectangular base plate 68 having a plurality of cuvette 
receptacles 70 projecting perpendicularly therefrom to receive the 
cuvettes, each receptacle 70 being provided with an entrance aperture 72 
and an exit aperture 74, which apertures, 72 and 74, face the wall 62. 
Each receptacle 70 is sized to receive a rectangular cuvette 76. 
Preferably, the base plate 68 is provided with pins 78, shown in FIG. 3, 
which protrude from the underside thereof. The pins 78 function as 
retaining elements which engage apertures 24 on the support plate 16 of 
the carrier 14 to secure the cuvette holder 22 thereto. 
With the cylindrical rod 38 locked in its initial position, the spring 
collar 48 is located close to block 50, and a first cuvette receptacle 80 
is positioned in a measuring position. In the terminal position, as shown 
in FIG. 1, leg 36 of bracket 30 is positioned close to block 52 and the 
last cuvette receptacle 81 on base plate 68 is in the measuring position. 
The pins 78 and the apertures 24 are preferably arranged such that base 
plate 68 can only be placed on support plate 16 in such a way that the 
entrance aperture 72 faces the entrance window 64, and the exit aperture 
74 faces the exit window 66. 
FIG. 2 shows the fluorescence radiation emitted normally with respect to 
the direction of the exciting radiation in dashed lines; the fluorescence 
radiation enters the fluorimeter through the housing 12 exit aperture 74 
and exit window 66, in which fluorimeter, for instance, the intensity of 
the total emission or its spectral distribution over a wider or smaller 
wavelength range is measured. 
Advantageously, the base plate 68 or the cuvette receptacles 70 may be 
designed with double walls and connected to a circulating thermostat. Such 
an arrangement is well known in the art and need not be described in 
detail herein. 
FIG. 3 depicts another embodiment of a cuvette holder 82 made of a 
sufficiently transparent plastic for radiation in the range of the 
investigation. The cuvette holder 82 is preferably formed integrally with 
the cuvettes and is designed to be used only once. The cuvette holder 82 
consists of a rectangular base plate 84 provided with a plurality of 
cuvette holders 86 projecting therefrom which are disposed diagonally with 
respect to the longitudinal direction of base plate 84 and are diagonally 
interconnected. Base plate 84, similar to base plate 68, is also provided 
with pins 78 protruding from the underside thereof, which pins 78 are 
adapted to engage apertures 24 on support plate 16. In this embodiment, 
the cuvette holder thermostatting may also be provided by designing 
support plate 16 with double walls and by connecting the same to a 
circulating thermostat. Alternatively, clamps may be provided instead of 
the pins to secure the base plate 84 to the support plate 16. 
The fluorimeter sampling apparatus described hereinbefore, particularly the 
one having the cuvette arrangement as shown in FIG. 3, may be readily 
combined with apparatus for preparing and processing samples as known in 
clinical chemistry for automatic series investigations (R. Haeckel; 
Rationalisierung des medizinischen Laboratoriums; GIT-Verlag Ernst 
Giebeler, Darmstadt 1976). 
While the present invention has been described herein with respect to 
specific embodiments, it will be apparent to those skilled in the art that 
such description is considered exemplary and is not deemed limiting. 
Hence, the scope of the present invention is defined by the appended 
claims and the reasonable interpretation thereof.