DEVICE FOR MEASURING THE FLUORESCENCE OF A MEDIUM

• US 20100282982A1
• Filed: 05/07/2010
• Published: 11/11/2010
• Est. Priority Date: 05/07/2009
• Status: Active Grant

• Current Assignee: Krohne Optosens GmbH
• Original Assignee: Krohne Optosens GmbH
• Inventors: FRITSCH, Thomas, SCHREIBER, Marco
• Granted Patent: US 8,872,133 B2
• Time in Patent Office: Days
• US Class Current: 250/459.1
• CPC Class Codes: G01N 2021/6491 Measuring fluorescence and transmission; Correcting inner filter effect
• CPC Class Codes: G01N 21/53 within a flowing fluid, e.g. smoke
• CPC Class Codes: G01N 21/6486 Measuring fluorescence of biological material, e.g. DNA, RNA, cells G01N21/6428 takes precedence
• CPC Class Codes: G01N 21/85 Investigating moving fluids or granular solids
• CPC Class Codes: G01N 2201/1211 for temperature

Abstract

A device for measuring the fluorescence of a medium having a radiation source, an emission-receiving element and an optical imaging element arranged on the sensor side of the optical imaging element, and a scattering-receiving element arranged on the sensor side of the optical imaging element and in which the radiation source, the imaging element and the emission-receiving element are aligned and configured relative to one another so that the medium present on the medium side of the imaging element can be illuminated by radiation from the radiation source, and the emission intensity of the medium radiation emitted by the medium based on fluorescence can be detected with the emission-receiving element. To provide a device for measuring the fluorescence of a medium which has an increased reliability in measuring the fluorescence, temperature compensation is performed relative to the temperature of the medium and/or at least one of the receiving elements.

Claims

1. Device for measuring the fluorescence of a medium, comprising:

at least one radiation source,

at least one emission-receiving element,

at least one optical imaging element, and

at least one scattering-receiving element

wherein the radiation source and the emission-receiving element are arranged on a sensor side of the optical imaging element,

wherein the radiation source, the imaging element and the emission-receiving element are aligned and configured with respect to one another so that a medium present on a medium side of the imaging element is illuminatable by radiation from the radiation source and the emission intensity of medium radiation emitted by the medium, based on fluorescence, is detectable with the emission-receiving element,

wherein the at least one scattering-receiving element is arranged on the sensor side of the optical imaging element so that the scattering intensity of medium radiation scattered by the medium in a range of the absorption of the radiation of the radiation source caused by the fluorescence is detectable with the scattering-receiving element, and

wherein a means for compensating for at least one of the temperature of the medium and the temperature of at least one of the receiving elements is provided.

2. Device according to claim 1, further comprising a reference receiving element and a beam splitter, wherein the beam splitter is arranged between the radiation source and the imaging element so as to guide a known reference radiation part of the radiation emitted from the radiation source to the reference receiving element so that the reference radiation is detectable by the reference receiving element and the source intensity of the radiation source is detectable by the reference receiving element, and wherein the beam splitter and the reference receiving element are aligned so as to prevent reflection of the medium being detected by the reference receiving element.

3. Device according to claim 1, further comprising an evaluating unit for calculating the fluorescence of the medium, and in addition to the emission intensity of the medium radiation emitted by the medium based on fluorescence detected by the emission-receiving element and conveyed to the evaluation unit, also calculating at least one of the scattering intensity of the medium radiation scattered by the medium in the range of the absorption of the radiation of the radiation source caused by a particular fluorescence and detected by the scattering-receiving element and conveyed to the evaluation unit and the source intensity of the radiation source detected by the reference receiving element and conveyed to the evaluation unit.

4. Device according to claim 3, wherein the evaluation unit is adapted for converting the detected emission intensity of the medium radiation emitted based on fluorescence in combination with the scattering intensity of the medium radiation scattered by the medium in the range of the absorption of the radiation of the radiation source caused by the fluorescence into a concentration value of the fluorescent parts of the medium.

5. Device according to claim 2, further comprising a source-side optical filter having bandpass characteristics, the source-side optical filter being arranged between the radiation source and one of the imaging element and the beam splitter, wherein the source-side optical filter is maximally permeable for the frequency range of the radiation of the radiation source with which the particular fluorescence of the medium is excitable.

6. Device according to claim 1, further comprising an optical emission filter having bandpass characteristics, the optical emission filter being arranged between the optical imaging element and the emission-receiving element, wherein the optical emission filter is maximally permeable for the frequency range of the medium radiation in which the radiation of the medium excited by a particular fluorescence lies.

7. Device according to claim 1, further comprising an optical scattering filter having bandpass characteristics, the optical scattering filter being arranged between the optical imaging element and the scattering-receiving element, wherein the optical scattering filter is maximally permeable in the frequency range of the medium radiation in which the medium has its absorption maximum caused by a particular fluorescence.

8. Device according to claim 1, wherein the radiation source is adapted to emit light with a radiation maximum at essentially 289 nm.

9. Device according to claim 5, wherein the source-side optical filter is a bandpass with a maximum permeability at essentially 289 nm.

10. Device according to claim 6, wherein the optical emission filter is a bandpass with a maximum permeability at essentially 340 nm.

11. Device according to claim 4, wherein the optical scattering filter is a bandpass with a maximum permeability at essentially 289 nm.

12. Device according to claim 1, wherein at least one of the emission-receiving and the scattering-receiving elements is a photomultiplier.

13. Method for fluorescent spectroscopic in-line determination of the protein content of a medium containing milk, comprising the steps of:

measuring the fluorescence of the medium using a device for measuring the fluorescence of a medium having at least one radiation source, at least one emission-receiving element and at least one optical imaging element, wherein the radiation source and the emission-receiving element are arranged on a sensor side of the optical imaging element, wherein the radiation source, the imaging element and the emission-receiving element are aligned and configured with respect to one another so that a medium present on a medium side of the imaging element is illuminated by radiation from the radiation source and the emission intensity of the medium radiation emitted by the medium based on fluorescence is detected with the emission-receiving element, wherein at least one scattering-receiving element is arranged and configured on the sensor side of the optical imaging element so that the scattering intensity of the medium radiation scattered by the medium in the range of the absorption of the radiation of the radiation source caused by a particular fluorescence is detected using the at least one scattering-receiving element.

14. Method according to claim 13, wherein the fluorescence of tryptophan is used for the determination of the protein content of a medium containing milk.