Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
  • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
  • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
  • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
  • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
  • G01N21/314—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry with comparison of measurements at specific and non-specific wavelengths
  • G01N2021/317—Special constructive features
  • G01N2021/3174—Filter wheel
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
  • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
  • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
  • G01N2021/3185—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry typically monochromatic or band-limited
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
  • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
  • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
  • G01N21/33—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using ultraviolet light

Definitions

• the present invention relates to a measuring device for determining a substance concentration of a fluid arranged in a measuring volume according to claim 1 and a corresponding method according to claim 9.
• Measuring accuracy in the largest possible concentration range of the substance to be measured important. It is equally important that the measurement accuracy is maintained over a long measuring period, so that calibration of the measuring device is as rare as possible, if at all unnecessary.
• the latter is used, for example, in the chromatographic separation of protein solutions.
• the absorption measurement controls a selection with regard to concentration and / or impurities based on the measurement results.
• a replacement substance can be used for the purpose of device calibration. This is particularly advantageous if the substance to be measured is expensive, has a poor resistance or this is generally difficult to handle.
• the object of the present invention is therefore to provide a measuring device and a method for determining a substance concentration, which allow the most accurate and long-term reproducible measurement.
• the invention is based on the idea to minimize unwanted effects of a source spectrum on the measurement / determination of the substance concentration. This is done according to the invention in particular by arranging a fluorescence-reducing element in the beam path, preferably between the detector and the measuring volume and limiting the
• Irradiation into the measuring volume in particular of the radiation having a wavelength deviating from the measuring wavelength, preferably short-wave radiation.
• Measuring wavelength or measuring wavelength range are used below as alternative names, but should each relate to both.
• the spectrum which arrives at a detector without influencing a substance to be measured in the measurement volume is regarded as the measurement spectrum.
• an optical determination in particular with an electromagnetic radiation in the measuring wavelength range between 1 nm and 5 ⁇ m, is preferred.
• the (decadic) logarithm of the quotient of transmitted (Lt) and irradiated (L0) light power at a given layer thickness D at each wavelength is proportional to the substance concentration c (in particular particle number per volume, for example mol / l) :
• the proportionality constant k will be called the absorption coefficient below.
• the relationship shown in the above equation applies to almost all substances over a wide concentration range.
• the transmitted light have the same wavelength and no scattering of the light takes place in the measuring volume.
• the practical measurement of A presupposes that the total optical radiation covers an approximately equal distance in the measuring volume. It is therefore preferred according to the invention if the measurement volume in the beam path direction is limited by plane-parallel windows and / or a measurement beam emitted by a measurement source runs approximately parallel, ie in particular non-scattering.
• the present invention is based in particular on the knowledge that with substances contained in the fluid to be measured
• a broad fluorescence light is produced at a measuring wavelength of 280 nm with a maximum at approximately 350 nm.
• Attenuation of the light at the measurement length by more than two Orders of magnitude. Furthermore, the fluorescence yield depends on the temperature and environment of the molecule and can be disturbed by other substances. Deviations from the linearity of the measurement result at different concentrations, so that the measurement results are less reproducible and scalable.
• the core of the present invention is therefore in particular the measurement of the spectral absorption for the determination of a substance concentration, wherein in the beam path both before and after the measurement volume
• wavelength selective means / components are arranged.
• wavelength-selective means / components are characterized in particular by the fact that radiation from the source spectrum in undesired wavelength ranges, ie in particular outside the measurement wavelength, is reduced more strongly than in the desired one
• wavelength-selective means are arranged, through which harmful
• Radiation of the source spectrum in particular in a short wavelength with respect to the measurement wavelength range, is reduced.
• the fluid arranged in the measuring volume is loaded as little as possible with radiation.
• the wave length-selective means arranged behind the measurement volume can in particular be a fluorescence-reducing element.
• the fluorescence-reducing element is preferably an interference filter with more than 10% transmission, in particular more than 20% transmission, preferably more than 30% transmission
• the source spectrum becomes the measurement wavelength
• the further wavelength-selective means / components can be formed, in particular, by forming the source as a narrow-band light source and / or an additional filter, which is preferably arranged downstream of the measurement volume and arranged in the beam path.
• the spectral distribution of the measuring radiation is preferably determined essentially by the wavelength-selective means arranged in front of the measuring volume, in particular a monochromator having a measuring wavelength of 280 nm and a maximum half-value width of 5 nm.
• the intensity of the measuring radiation is reduced by at most a factor of 10, preferably at most a factor of 5, by the wavelength-selective means arranged after the measuring volume.
• the fluorescent light is preferably at least a factor of 20, preferably reduced by at least a factor of 50, more preferably at least a factor of 100.
• An inventively preferred wavelength-selective means for wavelength selection before the measurement volume is a, in particular a narrow-band source spectrum emitting source.
• the wave selection can be done by providing a narrow band light source,
• the source may comprise a broadband light source with a downstream wavelength-selective intermediate element, in particular one of the following:
• optical elements are in particular discretely constructed one behind the other. It is alternative or additionally conceivable, in particular, to effect a spatial separation and the optical radiation (source spectrum) between individual
• the measuring device for determining the absorption is normalized or normalized to the intensity irradiated into the measuring volume. It is done in particular by the measuring volume with a not
• absorbing reference fluid is filled to one or more
• the wavelength-selective component connected downstream according to the invention is preferably a fluorescence-reducing element.
• a filter is used which significantly less influences the measurement wavelength to be measured by the detector than compared to the measurement wavelength
• the fluorescence-reducing element preferably has an absorption of less than 50%, more preferably less than 20%, at the measurement wavelength. In contrast, the fluorescence-reducing element has in the wavelength range in which a
• Fluorescence emission would stimulate the highest possible absorption.
• Beam path limiting component formed.
• the fluorescence-reducing element in particular with a radiation-direction-selective element,
• fluorescent radiation is at least predominantly reduced via the utilization of the different angular distribution, while the radiation to be measured at least predominantly passes through the fluorescence-reducing element and can be measured without the measurement at the detector
• Fluorescence radiation is significantly affected. This can be
• the detector for measuring the wavelength-related absorption of the source spectrum output by the source and passing through the measurement volume converts the measurement spectrum impinging on the detector into a photocurrent by means of an electrical current measurement.
• a photomultiplier in particular a photomultiplier, a photodiode semiconductor and / or a vacuum tube used.
• bolometric methods are conceivable since a wavelength-selected measurement spectrum impinges on the measuring wavelength on the detector.
• a bolometer can be used as the detector.
• the wavelength considered to be the measurement wavelength which at arithmetic averaging of, preferably weighted with the respective radiation intensity, at wavelength
• the measuring wavelength lies in particular between 2 ⁇ nm and 1 ⁇ m, preferably between 250nm and 320nm, more preferably at 280nm +/- 5nm and / or 260nm +/- 5nm and / or 254nm +/- 5nm, more preferably at 280nm +/- 0, 1 nm.
• the half-value width is, in particular, the distance, measured in wavelength, between the points in the intensity spectrum
• the half-width in accordance with the invention is in particular at most 1/5 of the measuring wavelength, preferably at most 1/1 of the measuring wavelength, more preferably at most 1/50 of the measuring wavelength.
• the thousandth of the width of the measuring radiation according to the invention is, in particular, the distance measured between the points in FIG.
• the millisecond is according to the invention in particular a maximum of half the measuring wavelength, preferably a maximum of a quarter of
• means for reducing shortwave and / or longwave radiation with respect to the measurement wavelength are at least a factor of 2, preferably at least a factor of 10, more preferably at least a factor of 100, based on the irradiated power density
• Measuring wavelength provided before entering the measuring volume a wavelength selection takes place between the measurement volume and the detector, the source spectrum being limited, in particular at least long-wave to the measurement wavelength, preferably with a decrease of at least a factor of 2, preferably at least a factor of 10, more preferably at least a factor of 1 00 to the measuring wavelength.
• the waste occurs in particular in an environment around the measuring wavelength, which is in particular 50/100, preferably 2/100.
• Figure 1 is a schematic, perspective view of a first
• Figure 2 is a schematic, perspective view of a second
• Embodiment of the measuring device according to the invention Embodiment of the measuring device according to the invention.
• FIG. 1 shows a source 1 which is formed from a light source 2 and a wavelength-selective optical element 3.
• Light source 2 is designed as a broadband light source, a
• broadband source spectrum outputs with a beam path 7, which extends, in particular linear, up to a detector 6.
• the broadband source spectrum of the light source 2 strikes the wavelength-selective optical element 3 and, when passing through the wavelength-selective optical element 3, radiation power is significantly reduced in the short-wave to a measurement wavelength of 280 nm.
• the wavelength-selective element 3 leaves a narrowband
• the narrowband source spectrum delimited at least below the measuring wavelength strikes a measuring volume 4 along the beam path 7.
• the measuring volume 4 is bounded by a measuring space which has windows 8, 8 'arranged transversely to the beam path 7 at least in the direction of the beam path 7.
• Beam path 7 arranged and preferably have a defined distance along the beam path 7. The distance corresponds to the layer thickness through which the narrow-band spectrum passes along the beam path 7 through a fluid arranged in the measurement volume.
• the fluid is arranged either in the measuring volume 4 static or transverse to the beam path 7.
• the fluid has a substance concentration to be determined of a substance (target substance), preferably tryptophan, which causes a measurable change by the detector 6 at the passing through the measurement volume 4 narrow-band source spectrum in the measurement wavelength range.
• a substance target substance
• tryptophan preferably tryptophan
• the narrow-banded source spectrum can cause a fluorescence, in particular caused by the target substance, in the measuring volume 4, which fluoresces, inter alia, along the beam path 7 to a falsification of
• the detector 6 can carry signals to be measured, in particular in a spectrum having a wavelength above the measuring wavelength.
• Fluorescence radiation at least predominantly, preferably largely, more preferably fully absorbed.
• the narrow-band spectrum provided for the measurement of the substance concentration, in particular short-wave and long-wave limited, meets the detector 6, which has its power density at least predominantly in the measurement length range.
• the measuring spectrum preferably has a maximum of the power density at the measuring wavelength.
• the fluorescence reducing element 5 is preferably selective at 280nm +/- 5nm and / or 260nm +/- 5nm and / or 254nm +/- 5nm.
• the detector 6 measures this from the measuring volume 4 and through the
• fluorescence-reducing element 5 passed light by conversion into a photocurrent via an electrical current measurement, in particular a photomultiplier. From this, it is possible to deduce the substance concentration of the target substance.
• FIG. 2 differs from the embodiment described in FIG. 1 in that a narrow-band light source 2 'is provided as the source 1, so that a light source 2' is provided
• the wavelength-selective optical element 3 can be omitted in this embodiment.
• the light source 2 ' is already at least one predominantly in the measuring wavelength range radiant source spectrum and thus includes the front of the measuring volume 4 arranged
• the fluorescence-reducing element 5 ' is preferably at least predominantly, preferably almost exclusively boring, selective to the measuring wavelength.

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• Physics & Mathematics (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Chemical & Material Sciences (AREA)
• Analytical Chemistry (AREA)
• Biochemistry (AREA)
• General Health & Medical Sciences (AREA)
• General Physics & Mathematics (AREA)
• Immunology (AREA)
• Pathology (AREA)
• Investigating, Analyzing Materials By Fluorescence Or Luminescence (AREA)

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• 2014
  • 2014-05-13 DE DE102014106748.7A patent/DE102014106748A1/de active Pending
• 2015
  • 2015-04-20 EP EP15721588.0A patent/EP3143382A1/de not_active Ceased
  • 2015-04-20 PL PL20195394.0T patent/PL3770585T3/pl unknown
  • 2015-04-20 WO PCT/EP2015/058517 patent/WO2015172977A1/de not_active Ceased
  • 2015-04-20 EP EP20195394.0A patent/EP3770585B1/de active Active
  • 2015-04-20 HU HUE20195394A patent/HUE065520T2/hu unknown
  • 2015-04-20 EP EP23210847.2A patent/EP4300079A3/de active Pending

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