WO1980000494A1 - Method for measuring the concentration by total reflection spectroscopy - Google Patents

Method for measuring the concentration by total reflection spectroscopy Download PDF

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Publication number
WO1980000494A1
WO1980000494A1 PCT/DE1979/000078 DE7900078W WO8000494A1 WO 1980000494 A1 WO1980000494 A1 WO 1980000494A1 DE 7900078 W DE7900078 W DE 7900078W WO 8000494 A1 WO8000494 A1 WO 8000494A1
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WO
WIPO (PCT)
Prior art keywords
intermediate layer
sample
substance
measurement
liquid
Prior art date
Application number
PCT/DE1979/000078
Other languages
German (de)
English (en)
French (fr)
Inventor
G Mueller
Original Assignee
G Mueller
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from DE2837769A external-priority patent/DE2837769C2/de
Priority claimed from DE19792928419 external-priority patent/DE2928419A1/de
Application filed by G Mueller filed Critical G Mueller
Publication of WO1980000494A1 publication Critical patent/WO1980000494A1/de

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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
    • G01N21/55—Specular reflectivity
    • G01N21/552—Attenuated total reflection

Definitions

  • the invention relates to a method for measuring the concentration by means of the spectroscopy of the total internal reflection.
  • a method for measuring the concentration by means of the spectroscopy of the total internal reflection is of great practical interest in particular for determining the concentration of biological substances, since it enables measurements with the smallest possible sample quantities directly in the biological environment.
  • This object is achieved according to the invention in that, for the regeneration of an optically clean surface of the reflection element, a transparent, highly refractive substance as an exchangeable intermediate layer between. Reflective element and sample is used.
  • the penetration depth of the transversely damped light wave penetrating into the adjacent sample substance during total reflection of the measuring beam path on the surface of the reflection element lies in the visible spectral range, e.g. in the range of fractions of a u and their field strength decreases exponentially with increasing depth of penetration.
  • the method according to the present invention enables the production and restoration of clean and reproducible surfaces between the reflection element and sample. This measure is the only way to ensure that the concentration of substances can be measured correctly and at any time by evaluating the absorption spectrum in the ultraviolet (UV), visible ( VIS) and infrared (IR) spectral range.
  • the substance for the intermediate layer can be selected to match the measurement problem so that no disturbing adsorption of the sample to be measured occurs and that it forms a non-toxic layer between the sample to be examined and the reflection element.
  • the method according to the invention finds particularly advantageous application for determining the concentration of biological substances, since the intermediate layer can always be selected in such a way that no disruptive adsorption occurs and that toxic effects are prevented.
  • the intermediate layer In order for the intermediate layer to be as thin as possible and yet to a large extent uniform in its thickness, it is advisable to use a liquid substance for its production.
  • This liquid intermediate layer can also be easily removed after the measurement has been completed, for example by wiping or washing off.
  • a thin film with an opening is advantageously placed on the reflection element in such a way that the reflection points lie in the region of the opening. The liquid substance is then introduced into this opening and evenly distributed therein.
  • a thin slide can also be used as the interchangeable intermediate layer, which consists of a material that refracts for the measuring radiation as strongly as or stronger than the reflection element and is arranged in optical contact with the reflection element by means of a suitable immersion liquid.
  • Such an intermediate layer consisting of solid material has the advantage that it forms an even stronger barrier than a liquid between the reflection element and the sample, since diffusion processes in this intermediate layer practically do not take place at the temperatures in question.
  • Such a specimen slide can also be provided on its surface facing the sample with a, preferably vapor-deposited or chemically applied, coating made of material that is highly refractive for the measuring radiation. This makes it possible to obtain different interfaces between the sample and the intermediate layer on the one hand and the reflection element or the immersion liquid and the intermediate layer on the other hand, that is to say these interfaces with an overall one-piece intermediate layer with different requirements of the sample on the one hand and of the reflection element on the other hand.
  • FIG. 2 shows a first exemplary embodiment of an arrangement for carrying out the method according to the invention with a liquid substance as the intermediate layer;
  • OMPI Fig. 4 shows another embodiment with a surface-coated solid substance as an intermediate layer.
  • optical refractive indices n relating to the spectral range of the measuring beam for the various media through which the measuring light beam used for the spectroscopy passes from the entry into the reflection element to the exit from it are indicated in the drawing.
  • the indices correspond to the reference numbers with which the respective element to which the refractive index provided with this index is assigned.
  • This measuring arrangement has a light source 1, which is preferably designed as a laser and which generates a light bundle 2 that is as well collimated as possible.
  • This light beam 2 passes through the entrance surface 3 of a reflection element 4 and is then totally reflected with a suitable choice of the angle of incidence ⁇ inside the reflection element 4 at the interface 5 between this reflection element and a sample 6 provided thereon, the number of reflections depending on the geometry of the Reflection element depends and should be adapted to the particular measurement problem.
  • the selection of a suitable form of the reflection element 4 is carried out according to criteria known per se, as described, for example, in the book "Internal Reflection Spectros copy” by NJ Harrick, published by the publisher John Wiey & Son Inc., New York 1967 is.
  • the transverse attenuated light wave which occurs during the total reflection of the light bundle 2 in the optically thinner medium, ie the sample 6, is influenced by the sample substance.
  • the spectral composition of the incident light beam 2 thus changes speaking of the absorption properties of the sample 6, so that a light bundle 7 is obtained when exiting the reflection element 4, the spectral composition of which is characteristic of the sample 6 in comparison to the light bundle 2. This change is determined as the absorption spectrum by means of the spectral apparatus 8 and the detector 9, an amplifier 10 is fed from there and is recorded, for example, by means of a recorder 11.
  • the light source 1, the spectral apparatus 8, the detector 9, the amplifier 10 and the recording device 11 have been omitted for the sake of a simplified illustration.
  • a liquid intermediate layer 12 is provided between the reflection element 4 and the sample 6.
  • a mask 13 which consists of a thin film and a central opening 13 'provided therein, is first placed on the reflection element 4 as an aid.
  • a small amount of liquid substance which is highly refractive for the measuring radiation is introduced into the opening 13 *, for example by means of a burette, with a glass rod, by dripping or the like, and the like
  • the liquid 12 must be such that it does not mix with the sample substance 6 and, of course, does not enter into an interfering connection with it.
  • 12 immersion oils such as Br, (CH) or C, H 7 Br or polymers such as polyvinyl carbazole and also resins are suitable as the high-refractive liquid.
  • polytrifluoroethylene oil in particular, can be used as the liquid substance for the intermediate layer 12
  • a further liquid substance for the intermediate layer 12 which is suitable for use in the infrared spectral range from 1 to 3.3 JU and 3.9 to 6.5 ⁇ and 7.5 to 40 JU, is paraffin oil, the optical permeability of which is in the wavelength ranges mentioned is essentially above 90% and its refraction
  • n ⁇ is between 1.480 to 1.484.
  • the film 13 is removed and the liquid intermediate layer 12 is wiped and / or washed off by the reflection element 4. Then in the Wei described above, a new liquid intermediate layer 12 is brought up by means of a new film 13 and in this way the next sample 6 is prepared for a spectroscopic examination.
  • FIG 3 shows an exemplary embodiment in which a slide 15 made of solid material is arranged as an intermediate layer between the sample 6 and the reflection element 4.
  • An immersion liquid 16 is provided to establish good optical contact between the reflection element 4 and the object carrier 15.
  • the slide 15 can be made of the same material as the reflection element.
  • the slide 15 can also consist of another suitable material which has a high refractive index in the spectral range of the measurement radiation.
  • the slide 15 can be made of glass or a polymer, for example.
  • the slide 15 can be made of germanium, silicon or selenium, or also particularly expediently from the material commercially available under the name "chalcogenide glass", which is characterized by a high transmission and a refractive index nft, 5 in the range 4 to 13 JJ and which is resistant to water and weak acids.
  • chalcogenide glass which is characterized by a high transmission and a refractive index nft, 5 in the range 4 to 13 JJ and which is resistant to water and weak acids.
  • the fixed slide 15 is provided on its surface facing the sample 6 with a coating 17, which is applied to the slide 15, for example, by vapor deposition or by chemical means.
  • This coating makes it possible, inter alia, to achieve an even higher refractive index at the interface between the sample 6 and the specimen slide 15 or, if the material of the specimen slide 15 is relatively free to choose, a material which is particularly suitable for the particular type of sample substance 6 currently used to provide the interface between the sample 6 and the slide 15.
  • object carrier 15 or coating 17 can also be provided in the IR spectral range as object carrier 15 or coating 17: aN0 3 , calcite, quartz, LiF, MgF ⁇ , CaF, SrF, PbF 2 , T-12, NaF, BaF 2 , KF, CsF, NaCl, NaBr, KCl, NaJ, KBr, CsCL, AgCl, TICl, KRS-6, AgBr, KJ, TIBr, CsBr, KRS-5, CsJ.
  • aN0 3 calcite, quartz, LiF, MgF ⁇ , CaF, SrF, PbF 2 , T-12, NaF, BaF 2 , KF, CsF, NaCl, NaBr, KCl, NaJ, KBr, CsCL, AgCl, TICl, KRS-6, AgBr, KJ, TIBr, CsBr, KRS-5, CsJ.
  • a copolymer of polyethylene and polypropylene being suitable as a polymer, in particular preferably one with a ratio of 97, for the fingerprint area : 3 between polyethylene and polypropylene.
  • the described method enables the prevention of undesired adsorption on the surface of the reflection element and, in addition to the prevention of an undesirable influence of the reflection element on the sample owing to its toxicity and / or water solubility, with a suitable selection of the intermediate layer, the achievement of an increased detection sensitivity by using the intermediate layer material in this way selects that certain substances from the sample are adsorbed on this intermediate layer.

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  • Physics & Mathematics (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 Or Analysing Materials By Optical Means (AREA)
PCT/DE1979/000078 1978-08-30 1979-08-02 Method for measuring the concentration by total reflection spectroscopy WO1980000494A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE2837769A DE2837769C2 (de) 1978-08-30 1978-08-30 Vorrichtung zur Bestimmung der Konzentration biologischer Substanzen in Mehrkomponenten-Systemen
DE2837769 1978-08-30
DE19792928419 DE2928419A1 (de) 1979-07-13 1979-07-13 Verfahren zur bestimmung der konzentration biologischer substanzen

Publications (1)

Publication Number Publication Date
WO1980000494A1 true WO1980000494A1 (en) 1980-03-20

Family

ID=25775581

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/DE1979/000078 WO1980000494A1 (en) 1978-08-30 1979-08-02 Method for measuring the concentration by total reflection spectroscopy

Country Status (3)

Country Link
EP (1) EP0016166A1 (enrdf_load_stackoverflow)
JP (1) JPS55500589A (enrdf_load_stackoverflow)
WO (1) WO1980000494A1 (enrdf_load_stackoverflow)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0221011A3 (de) * 1985-09-26 1989-11-02 Ciba-Geigy Ag Analysenverfahren, unter Verwendung der abgeschwächten Totalreflexion
WO2003100497A1 (de) * 2002-05-23 2003-12-04 Erhard Wendlandt Beleuchtung für mikroskop

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3436159A (en) * 1966-02-04 1969-04-01 Bausch & Lomb Internal reflection element for spectroscopy with film optical cavity to enhance absorption
US3999855A (en) * 1974-10-24 1976-12-28 Block Engineering, Inc. Illumination system

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3436159A (en) * 1966-02-04 1969-04-01 Bausch & Lomb Internal reflection element for spectroscopy with film optical cavity to enhance absorption
US3999855A (en) * 1974-10-24 1976-12-28 Block Engineering, Inc. Illumination system

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
Analytical Chemistry, Band 38, Nr. 1, Januar 1966, herausgegeben 1966, Washington D.C. (US), Seite 160, R. JOHNSON et al.: "Silver membrane filters as a support for infrared analysis by attenuated total reflection", siehe Seite 160. *
R. MILLER et al.: "Laboratory Methods in Infrared Spectroscopy", Teil 14 A practical approach to internal reflection spectroscopy, Seiten 205 bis 229, herausgegeben von Verlag Heyden, London, 1972, siehe insbesondere Seiten 218 bis 227. *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0221011A3 (de) * 1985-09-26 1989-11-02 Ciba-Geigy Ag Analysenverfahren, unter Verwendung der abgeschwächten Totalreflexion
WO2003100497A1 (de) * 2002-05-23 2003-12-04 Erhard Wendlandt Beleuchtung für mikroskop

Also Published As

Publication number Publication date
EP0016166A1 (de) 1980-10-01
JPS55500589A (enrdf_load_stackoverflow) 1980-09-04

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