METHOD AND APPARATUS FOR LUMINESCENCE MEASUREMENT

Abstract: The invention relates to a method and an apparatus for luminescence measurement of samples in transparent multi­ well plates or strips. A luminescence instigating reagent is added to the samples in sequence to instigate a luminescence reaction in each sample, and the resulting photon emission from each well is measured during a predetermined measure­ ment period. According to the invention an on-going lumines­ cence reaction is actively interrupted at the end of the measure­ ment period before a corresponding reaction is instigated in the next sample.

Description: Method and Apparatus for Luminescence Measurement. TECHNICAL FIELD The present invention relates to a method for luminescence measurement of samples in transparent multi-well plates or strips, comprising adding a luminiscence instigating reagent to the samples in sequence to instigate luminescence reactions, and measuring the resulting photon emission during a predetermined measurement period, as well as an apparatus for carrying out the method. BACKGROUND ART Luminometry is an established method in biochemistry and immunology.In luminometric assays or measurements the luminescence reaction, i.e. the photon emission, is initiated in that an activating reagent is added to the samples to be measured, whereupon the photon emission is measured by means of a photon-detector during a predetermined measurement period. Any chemical component necessary for the luminescence reaction can be used as activating reagent. The reaction is started instantaneously when the activating reagent mixes with the other components of the sample and lasts a certain period of time depending on the speed of the reaction, which in its turn is dependent on the decay time constant of the reaction. The decay time constants in luminometric as says typically range from about 10 seconds to a couple of hours. From EP 25350 it is known to use transparent multi-well plates or strips as sample containers. In the apparatus according to EP 25350 the luminescence reactions are instigated and measured in a row of wells at the same time. In order to prevent the occurence of crosstalk between the wells, a plate support is provided, which has a grid-like structure of opaque partitions which form individual compartments for containing the bottom portions of the wells of the plate or strip. Such partitions can, however, not completely prevent photons from the reaction in one well to impinge on the photon-detectors that measure the reactions in adjacent wells. DISCLOSURE OF INVENTION The object of the present invention is to render it possible in a simple manner to use multi-well plates or strips as sample containers in connection with luminescence measurements without the use of the above opaque partitions. This is attained according to the present invention in that an on-going luminescence reaction is actively interrupted at the end of the measurement period before a corresponding reaction is instigated in the next sample. DETAILED DESCRIPTION So far, conventional transparent multi-well plates or strips have required support plates having opaque partitions which form individual compartments for the wells of the multi-well plate or strip in order for such plates or strips to be used as sample containers in connection with luminescence measurements, since the luminescence reactions continue in the samples after that they have been measured. In order to make it possible in a simple manner to use conventional transparent multi-well plates and strips as sample containers at luminescent measurements according to the present invention the luminescence reactions are instigated and measured in one well at a time and at the end of the respective measurement period the on-going luminescence reaction is actively interrupted in the sample that is being measured before a corresponding reaction is instigated in the following sample. According to a first embodiment of the present invention the on-going luminescence reaction can be actively interrupted by the addition to the sample of a luminescence quenching reagent. The nature and composition of this luminescence quenching reagent depends on the luminescence system used for the assay in question. A number of possible quenching reagents are available which very effectively quench the luminescence within one or two seconds. As examples of luminescence quenching reagents acids can be mentioned such as trichlor acetic acid, hydrochloric acid and acetic acid. A change of pH normally quenches the chemiluminescence of bioluminescence reactions quite effectively. Moreover, the use of precipitating reagents is possible, e.g. ammonium sulphate which precipitates proteins and enzymes and prevents them from contributing to the luminescence reactions. As a further example metallic catalyzators can be mentioned, which are typical for bioluminescence systems and can be trapped with a suitable chelating agent, so that the luminescence is eliminated. Luminometers for luminescence measurements of samples that successively caaeintoa measurment position, comprise in the measurement position a dispensing means for dispensing the luminescence instigating reagent in sequence to the samples to instigate luminescence reactions in the samples, and a photon-detector which is adapted to measure the photon emission from the respective sample during a pre-determined measurement period. According to the invention a quenching means is also provided in the measurement position. According to a first embodiment of the apparatus according to the present invention this quenching means can be adapted to add the above luminescence quenching reagent to the sample at the end of the respective measurement period in order to interrupt the on-going luminescence reaction before a corresponding reaction is initiated in the following sample. According to a second embodiment of the apparatus according to the present invention the quenching means can be adapted to empty the well in which the luminescenc reaction is going on before the luminescence quenching reagent is added in order to quench the luminescence reaction going on in any residues of the sample in the well. The wells can be emptied,e.g. by means of a suction pump. With such an arrangement it will quite easily be possible to use conventional transparent multi-well plates and strips as sample containers for luminescence measurements in a luminometer.

Claims: CLAIMS 1. Method for luminescence measurement of samples in transparent multi-well plates or strips, comprising adding a luminescence instigating reagent to the samples in sequence to instigate luminescence reactions, and measuring the resulting photon emission during a predetermined measurement period, characterized in that an on-going luminescence reaction is actively interrupted at the end of the measurement period before a corresponding reaction is instigated in the next sample. 2. Method according to claim 1, characterized in that the on-going luminescence reaction is interrupted in that a luminescence quenching reagent is added. 3. Method according to claim 2, characterized in that the well in which the reaction is going on is emptied before the quenching reagent is added. 4. Apparatus for luminescence measurement of samples in transparent multi-well plates or strips, comprising dispensing means for dispensing a luminescence instigating reagent in sequence to the samples to instigate a luminescence reaction in each sample, and a photondetector adapted to measure the resulting photon emission from the respective samples during a predetermined measurement period, characterized in that a means is provided to actively interrupt an on-going luminescence reaction at the end of the measurement period before a corresponding reaction is instigated in the next sample. 5. Apparatus according to claim 4, characterized in that said means is adapted to interrupt the on-going luminescence reaction by adding a luminescence quenching reagent. 6. Apparatus according to claim 4, characterized in that a means is provided for emptying the well in which the reaction is going on before the quenching reagent is added.

Inventors: SOINI, ERKKI
Applicants: WALLAC OY
Application year: 1984
Main classification: G01N21
IPC codes: G01N21