GB958025A - Method for providing automatic background correction in optical densitometry and apparatus therefor - Google Patents

Method for providing automatic background correction in optical densitometry and apparatus therefor

Info

Publication number
GB958025A
GB958025A GB1268760A GB1268760A GB958025A GB 958025 A GB958025 A GB 958025A GB 1268760 A GB1268760 A GB 1268760A GB 1268760 A GB1268760 A GB 1268760A GB 958025 A GB958025 A GB 958025A
Authority
GB
United Kingdom
Prior art keywords
light
sample
waveband
photo
optical density
Prior art date
Legal status (The legal status 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 status listed.)
Expired
Application number
GB1268760A
Inventor
Ian Elcock Bush
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
National Research Development Corp UK
Original Assignee
National Research Development Corp UK
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
Application filed by National Research Development Corp UK filed Critical National Research Development Corp UK
Priority to GB1268760A priority Critical patent/GB958025A/en
Publication of GB958025A publication Critical patent/GB958025A/en
Expired legal-status Critical Current

Links

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
    • 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
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J1/00—Photometry, e.g. photographic exposure meter
    • G01J1/10—Photometry, e.g. photographic exposure meter by comparison with reference light or electric value provisionally void
    • G01J1/16—Photometry, e.g. photographic exposure meter by comparison with reference light or electric value provisionally void using electric radiation detectors
    • G01J1/18—Photometry, e.g. photographic exposure meter by comparison with reference light or electric value provisionally void using electric radiation detectors using comparison with a reference electric value
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
    • G01J3/12—Generating the spectrum; Monochromators
    • G01J2003/1213—Filters in general, e.g. dichroic, band
    • G01J2003/1217—Indexed discrete filters or choppers
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
    • G01J3/12—Generating the spectrum; Monochromators
    • G01J3/14—Generating the spectrum; Monochromators using refracting elements, e.g. prisms
    • 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
    • G01N21/59—Transmissivity
    • G01N21/5907—Densitometers
    • G01N21/5911—Densitometers of the scanning type
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
    • G01N30/90—Plate chromatography, e.g. thin layer or paper chromatography
    • G01N30/94—Development
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
    • G01N30/90—Plate chromatography, e.g. thin layer or paper chromatography
    • G01N30/95—Detectors specially adapted therefor; Signal analysis

Landscapes

  • 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 Or Analysing Materials By Optical Means (AREA)

Abstract

958,025. Optical density measurement. NATIONAL RESEARCH DEVELOPMENT CORPORATION. April 6, 1961 [April 8, 1960], No. 12687/60. Heading G1A. In a method and apparatus for measuring the optical density of a substance absorbed by, or deposited on, a carrier material, a portion of the carrier is scanned alternately with light in a narrow wave-band including a maximum absorption wavelength of the substance, and with light in a narrow wave-band including a wavelength distant from that of any maximum absorption wavelength. A photoelectric system is used to detect the light transmitted or reflected by the carrier in each case, the resultant signals being compared to obtain a signal indicative of the optical density of the substance. In the embodiment described the photo-electric system comprises a photo-multiplier tube T. A scanning spot of light is generated by means of a rotating slotted disc R3 and slit S1 which receive light from a source not illustrated. The light spot is deflected by mirrors through a monochromator comprising a prism P, one or other of the Littrow mirrors L1, L2, and slot S2. Mirror L2 is periodically moved to the position shown in broken line, thereby changing the waveband of the light emerging from the slit from one value to the other. The light passes through the test sample Q, e.g. a filter paper, to the photo-multiplier. In this embodiment, the sample Q is moving continuously and, in order that the second waveband scan takes place over the same area as did the first, it is necessary to displace the second scan in the direction of motion of the sample. This is done by means of a transparent plate R2 which is periodically interposed between the slits S2 and S3. The detector output passes to a circuit which generates an output signal which is linear in respect to the logarithm of the light intensity. After amplification this signal is switched by means of an electronic switch to one or other of two integrating circuits, dependant upon which waveband is illuminating the sample. A meter and chart recorder receive the difference of the two integrated signals, this difference indicating the optical density of the substance. The electronic switches are controlled by means of photo-transistor circuits associated with light stops mounted on the mirror L2, and it is so arranged that no signal is passed to either integrator during change-over from one waveband to the other. The motion of the sample Q is synchronized with the drive of R2 and L2. If A.C. amplification is used in the apparatus it is necessary to chop the light beam, for example by means of a further rotary element prior to slit S1.
GB1268760A 1960-04-08 1960-04-08 Method for providing automatic background correction in optical densitometry and apparatus therefor Expired GB958025A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB1268760A GB958025A (en) 1960-04-08 1960-04-08 Method for providing automatic background correction in optical densitometry and apparatus therefor

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB1268760A GB958025A (en) 1960-04-08 1960-04-08 Method for providing automatic background correction in optical densitometry and apparatus therefor

Publications (1)

Publication Number Publication Date
GB958025A true GB958025A (en) 1964-05-13

Family

ID=10009294

Family Applications (1)

Application Number Title Priority Date Filing Date
GB1268760A Expired GB958025A (en) 1960-04-08 1960-04-08 Method for providing automatic background correction in optical densitometry and apparatus therefor

Country Status (1)

Country Link
GB (1) GB958025A (en)

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