Optics: measuring and testing – For light transmission or absorption – Of fluent material
Reexamination Certificate
2000-03-28
2002-05-28
Rosenberger, Richard A. (Department: 2877)
Optics: measuring and testing
For light transmission or absorption
Of fluent material
C356S246000
Reexamination Certificate
active
06396584
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a pipette adapter suitably usable for measuring the absorbance of a sample in the field of pharmaceutical industry and the like, an absorbance measuring pipette comprising this pipette adapter and a pipette, and a tip attachable to this pipette adapter, as well as an absorbance measuring apparatus and absorbance measuring method for measuring the absorbance of a sample by using this absorbance measuring pipette.
2. Related Background Art
In a wide range of fields such as pharmaceutical industry, food industry, chemical industry, agriculture, forestry, and fishery, samples are analyzed by measuring their absorbance for studying and developing new drugs, screening enzymes, analyzing microorganisms, and so forth. Among such analyzing methods, examples of methods for analyzing biological samples, such as nucleic acids, proteins, and the like, which are important in bio-related fields, include the following:
(1) Since biological samples as a specimen exist by only a minute amount in general, and their quantitative determination is also important, a sample is transferred to a specific cell for measuring a minute amount. The cell containing this sample is irradiated with test light. The intensity of test light transmitted through the cell and sample is detected, and the absorbance of the sample is measured according to the result of this detection. In this case, for putting the sample into the cell, a pipette
10
and a tip
30
, such as those as shown in
FIG. 11
, are used. The tip
30
is detachably attachable to the front end of the pipette
10
, and the sample is metered into the tip
30
.
(2) U.S. Pat. No. 5,844,686 discloses a method using a tip having a window for introducing test light or a reflecting mirror for reflecting the test light, attaching this tip to the front end of a pipette, and measuring the absorbance of a sample while the latter is contained in the tip. This method aims at improving the recovery ratio of the sample, preventing the sample from being contaminated upon recovery, and carrying out rapid measurement of absorbance.
SUMMARY OF THE INVENTION
The inventors have found that the following problems exist in the above-mentioned conventional absorbance measuring methods. Namely:
1) In samples such as nucleic acids, proteins, and the like, subsequent reactions are often carried out after the measurement of absorbance. In such a case, it is necessary for the sample contained in the cell for absorbance measurement to be recovered after the measurement. However, the method of above-mentioned (1) is problematic in that the recovery ratio of the sample is insufficient, the sample is contaminated upon recovery, the cell is hard to wash, and so forth.
2) The method of the above-mentioned (2), on the other hand, has problems as follows. In general, for preventing the problem of contamination from occurring, the tip is used only once and is discarded without being reused. Providing such a disposable tip with the above-mentioned window or reflecting mirror is inappropriate in that the tip becomes expensive. For reusing the tip without discarding it, washing is necessary for the tip also acting as a cell. Further, since the tip has a window for introducing test light or a reflecting mirror for reflecting the test light, it is difficult for the tip to be made smaller, whereby the invention disclosed in the above-mentioned publication is not effective for a sample having a small amount (minute amount in particular).
Therefore, in order to overcome the above-mentioned problems, it is an object of the present invention to provide a pipette adapter, an absorbance measuring pipette, an absorbance measuring apparatus, and an absorbance measuring method, by which the step of recovering a sample can be omitted, the sample can be prevented from being contaminated upon recovery, no specific cell for measurement is necessary, and the absorbance of a small amount of sample can be measured by use of an inexpensive tip.
For achieving such an object, the inventors have accomplished the present invention. Namely, the pipette adapter in accordance with the present invention is one usable together with a pipette for measuring an absorbance of a sample including a specimen, attachable between the pipette and a tip adapted to contain the sample, having an inner space continuing to respective internal spaces of the pipette and tip when attached thereto, and comprising test light introducing means for introducing test light into the inner space from outside and emitting the test light toward a sample suction port of the tip.
Thus configured pipette adapter is used as being attached between the pipette and the tip. In its attached state, the respective internal spaces of the pipette adapter, pipette, and tip are continuous. By the test light introducing means, the test light is introduced into the inner space of the pipette adapter from outside and is reflected toward the sample suction port of the tip. As a consequence, the test light is transmitted through the sample contained in the tip, whereby the absorbance of the sample can be measured. As the pipette and tip, those conventionally sold and utilized can be employed. Also, a tip made of an inorganic material such as glass, stainless steel, or the like can be used.
Preferably, the test light introducing means of the pipette adapter in accordance with the present invention comprises a test light introducing window for introducing the test light into the inner space from outside and a reflecting mirror for reflecting toward the sample suction port of the tip the test light introduced into the inner space through the test light introducing window. In this case, the test light is introduced into the inner space of the pipette adapter through the test light introducing window from outside and is reflected by the reflecting mirror so as to be emitted toward the sample suction port of the tip.
Preferably, the test light introducing means comprises an optical fiber which emits, from one end thereof disposed within the inner space toward the sample suction port of the tip, the test light guided therethrough from outside. As a consequence, the test light is guided through the optical fiber from outside and is emitted toward the sample suction port of the tip from one end of the optical fiber located within the inner space of the pipette adapter. More preferably, in this case, test light collecting means, disposed near the above-mentioned one end of the optical fiber, for collecting the test light is further provided.
Also, more preferably, the test light introducing means selectively emits toward the sample suction port of the tip only a predetermined wavelength band component of the test light introduced into the inner space from outside. As a consequence, wavelength components unnecessary for absorbance measurement can be restrained from irradiating the sample, whereby the sample within the tip can be prevented from raising its temperature.
The absorbance measuring pipette in accordance with the present invention comprises the pipette adapter in accordance with the present invention and a pipette attachable to the pipette adapter. The pipette adapter and the pipette may be detachable from each other or may be used as being integral with each other. In the case where they are detachable from each other, the pipette adapter can be washed easily as necessary. When they are integral with each other, on the other hand, their handling can be improved.
It will be useful if a tip having an inserting portion, in a substantially conical or pyramidal form, for receiving the pipette adapter, and a sample container portion, in a tubular form, having an end part formed with the sample suction port is further provided. If such a tip is used for drawing in the sample by suction, and the sample is held in the sample container portion of the tip, then the reproducibility in measuring the absorbance of the sample can be enhanced. If the tubular sample container portion is made na
Hiramatsu Mitsuo
Taguchi Takeshi
Hamamatsu Photonics K.K.
Leydig , Voit & Mayer, Ltd.
Rosenberger Richard A.
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