Method and apparatus for photometric analysis of substantially colorless components of sample

• US 3,874,794 A
• Filed: 04/20/1973
• Issued: 04/01/1975
• Est. Priority Date: 04/21/1972
• Status: Expired due to Term

• Current Assignee: Bodenseewerk Perkin-Elmer GmbH (Revvity, Inc.)
• Original Assignee: Albert Schmitt, Hans Vogel, Toma Tomoff
• Inventors: Schmitt, Albert, Vogel, Hans, Tomoff, Toma
• Primary Examiner(s): McGraw, Vincent P.
• Application Number:
  US05/352,887
• Time in Patent Office: 711 Days
• Field of Search: 356/36,184,180,39 23/23B,23R
• US Class Current: 356/36
• CPC Class Codes: G01N 21/78 producing a change of colour

Abstract

This is a method for quantative photometric determination of substantially colorless components of a sample by reaction with a color-producing reagent and subsequent determination of the colored reaction product at a specific wavelength. The method is particularly adapted to determined at least two components in the sample, the second of which may require the addition of a second reagent, for example, to chemically '"'"''"'"''"'"''"'"'free'"'"''"'"''"'"''"'"' the second component. The technique first measures the optical transmission of a known amount of sample diluted by a known amount of diluent to determine a '"'"''"'"''"'"''"'"'blank'"'"''"'"''"'"''"'"' absorbance value; a known quantity of a color-producing reagent is then added in excess and an absorbance value is determined; and finally, a metered quantity of a reagent which frees the combined component is added and a third absorbance value is measured. From there three absorbance values the concentration of each of the two components may be readily determined.

Claims

1. A METHOD FOR THE QUANTITIATIVE PHOTOMETRIC DETERMINATION OF SUBSTANTIALLY COLORLESS COMPONENTS OF A SAMPLE BY REACTION WITH A COLOR-PRODUCING REAGENT AND SUBSEQUENT DETERMINATION OF THE ABSORBANCE OF THE COLORED REACTION PRODUCT AT A SPECIFIC WAVELENGTH, COMPRISING AS A FIRST GROUP OF STEPS, INTRODUCING A METERED SAMPLE VOLUME INTO A CELL (17) AND DILUTION BY A METERED QUANTITY OF A DILUENT AND AFTER INTIMATE MIXING A FIRST OPTICAL TRANSMISSION VALUE CORRESPONDING TO THE BLANK VALUE IS MEASURED, AND AS A SECOND GROUP OF STEPS, A METERED QUANTITY OF A COLOR-PRODUCING REAGENT IS ADDED TO THE SAMPLE AND DILUENT AND AFTER INTIMATE MIXING A SECOND OPTICAL TRANSMISSION VALUE IS MEASURED.

2. A method as claimed in claim 1 for the determination of at least two components in a sample, a first component being determinable directly and a second component only after adding another reagent, further comprising:

a third group of steps, a metered quantity of a second color-producing reagent is added to the sample, diluent and first reagent mixture and after intimate mixing a third optical transmission value is measured.

3. A method as claimed in the claim 2 for the determination of a sample component present partially in a free and partially in a combined quantity, in which:

in said second group of steps, a metered excess quantity of the first color-producing reagent is added and a third transmission value corresponding to the free partial quantity is measured, while in the third group of steps, a metered quantity of another reagent for setting free the combined partial quantity is added and a transmission value corresponding to the total quantity is measured.

4. A method as claimed in claim 1, in which:

from the measured transmission values are computed quantities at least proportional to the respective absorbance (extinction) and concentration values, which may then be directly recorded.

5. A method as claimed in the claim 4, in which:

the change of said quantities at least proportional to the respective absorbance (extinction) and concentration with time is recorded.

6. A method as claimed in claim 1, in which:

the supply of the metered sample and reagent volumes to the cell (17) successively is accomplished in a controlled time sequence, and the intimate mixing and optical measurement are carried out automatically.