Chemistry: molecular biology and microbiology – Measuring or testing process involving enzymes or... – Involving viable micro-organism
Reexamination Certificate
1995-03-08
2001-05-01
Ludlow, Jan (Department: 1743)
Chemistry: molecular biology and microbiology
Measuring or testing process involving enzymes or...
Involving viable micro-organism
C435S029000, C435S288400
Reexamination Certificate
active
06225079
ABSTRACT:
BACKGROUND OF THE INVENTION
One form of microtitration unit for testing and analysing for example biological fluids has at least one container of transparent material, for accommodating a biological test reaction mixture, with an opening for introducing the mixture.
Microtitration units of that kind which are often in the form of a plate having a plurality of containers arranged in juxtaposed relationship may be used for the routine investigation of biological fluids for medicament residues. The investigation essentially extends to the presence of antibiotics and sulfonamides. For that purpose the containers are partially filled with a biological test reaction mixture which is usually made up on the basis of agar-agar nutrient media and contains test micro-organisms and a color indicator. The biological fluid to be investigated, for example milk, is pipetted on to the biological test reaction mixture in the container. The container is then possibly closed and then incubated at the optimum temperature for the test micro-organisms in an incubation cabinet or in a water bath. During the incubation operation any medicament residue in the biological fluid to be investigated diffuse out of same into the test reaction mixture and impede metabolism of the test micro-organism. If metabolism occurs, there is a change in color of the color indicator, for example from blue to yellow whereas the presence of medicament residues is indicated by the absence of a change in color.
In order to be able to detect all possible medicament residues, tests are required, with at least two different test reaction mixtures, and that requires a plurality of test operations and is accordingly time-consuming and expensive.
SUMMARY OF THE INVENTION
An object of the present invention is to improve a microtitration unit in such a way that a sample can be subjected to tests in one working operation, using a plurality of different test reaction mixture.
Another object of the present invention is to provide a microtitration unit which affords simplicity of operation while giving reliable testing results.
In accordance with the invention the foregoing and other objects are attained by a microtitration unit comprising at least one container of transparent material. The container is subdivided into at least two chambers for accommodating different test reaction mixtures, by at least one partition which extends from the inside of the bottom of the container and which is of smaller height than the internal height of the container.
As will be seen in greater detail hereinafter in connection with preferred embodiments of the invention, a plurality of different test reaction mixtures can be introduced into the container of the microtitration unit or a plurality of containers where the unit has more than one container, more specifically preferably in such a way that the partition is allowed to project upwardly slightly above the respective filling levels of the different test reaction mixtures introduced into the container. When then the biological fluid to be tested is subsequently introduced for example by means of a pipette, the biological fluid floods over the different test chambers of the container if such an amount of biological test fluid is introduced by means of the pipette, that the test fluid also floods over the top edge of the partition. In a subsequent incubation operation any medicament residues which are possibly present can then diffuse out of the sample which has jointly introduced by means of the pipette for the different test reaction mixtures, into the respective test reaction mixtures, and possibly impede metabolism of the respective test micro-organism. The test reaction mixtures which are introduced into the individual chambers of a respective container are suitable for indicating different medicament residues so that as a result a test with a plurality of test reaction mixtures and accordingly optimum detection can be effected by one operation of introducing a fluid to be investigated, as by means of a pipette.
If there are no medicament residues in the biological fluid to be investigated, a change in color occurs in all chambers of the container. If the biological fluid to be investigated contains medicaments in relatively small amounts, it is possible that only the test reaction mixture in one chamber of the container reacts positively. That result can then give a clear indication of the nature of the medicament residue present.
Further objects, features and advantages of the invention will be apparent from the following description of preferred embodiments.
REFERENCES:
patent: 2874091 (1959-02-01), Fisk
patent: 3126325 (1964-03-01), Poole
patent: 3597326 (1971-08-01), Liner
patent: 3941658 (1976-03-01), Lameris et al.
patent: 4247634 (1981-01-01), Abdou
patent: 4255522 (1981-03-01), Fusenig et al.
patent: 4999303 (1991-03-01), Jaeger et al.
Bierman, Muserlian and Lucas
Gist-Brocades N.V.
Ludlow Jan
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