Method of and device for analyzing one ingredient in a mixed solution with two light beams of different wavelengths

• US 4,299,487 A
• Filed: 04/04/1979
• Issued: 11/10/1981
• Est. Priority Date: 04/05/1978
• Status: Expired due to Term

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Kuroishi, Tadafumi, Honkawa, Tadashi, Sengoku, Masayuki, Komori, Ritsuo
• Primary Examiner(s): Church, Craig E.
• Application Number:
  US06/027,099
• Time in Patent Office: 951 Days
• Field of Search: 356/320, 250/343, 250/344, 250/345, 250/346
• US Class Current: 356/320
• CPC Class Codes: G01J 3/427 Dual wavelengths spectrometry
• CPC Class Codes: G01N 21/314 with comparison of measurements at specific and non-specific wavelengths dual wavelength spectrometry G01J3/427

Abstract

A method of and device for analyzing one ingredient in a mixed solution with two light beams of different wavelengths are disclosed which include the following processes. A light beam from a light source are divided into a first light beam having a wavelength of λ₁ and a second light beam having a wavelength of λ₂. The wavelength λ₁ is fixed, and λ₂ is variable, for example, a scanning wavelength. Reference signals E.sub.λ.sbsb.1 and E.sub.(λ.sbsb.2.sub.) respectively corresponding to the fixed wavelength λ₁ and the variable wavelength (λ₂) are produced from photometric signals resulting from the passage of the first and second light beams through only a solvent. After having been normalized by the reference signals E.sub.λ.sbsb.1 and E.sub.(λ.sbsb.2.sub.), the photometric signals Ib.sub.λ.sbsb.1 and Ib.sub.(λ.sbsb.2.sub.) resulting from the passage of the first and second light beams through a solution containing only a coexisting ingredient are converted into absorbance signals b.sub.λ.sbsb.1 and b.sub.(λ.sbsb.2.sub.). These absorbance signals are held as a ratio indicating signal k.sub.(λ.sbsb.2.sub.) =b.sub.(λ.sbsb.2.sub.) /b.sub.λ.sbsb.1. After having been normalized by the reference signals E.sub.λ.sbsb.1 and E.sub.(λ.sbsb.2.sub.), the photometric signals Ic.sub.λ.sbsb.1 and Ic.sub.(λ.sbsb.2.sub.) resulting from the passage of the first and second light beams through the mixed solution containing the coexisting ingredient and the ingredient to be analyzed are converted into absorbance signals C.sub.λ.sbsb.1 and C.sub.(λ.sbsb.2.sub.). A product signal k.sub.(λ.sbsb.2.sub.).C.sub.λ.sbsb.1 is produced from the absorbance signal C.sub.λ.sbsb.1 and the ratio indicating signal k.sub.(λ.sbsb.2.sub.). A signal ΔDS=a.sub.(λ.sbsb.2.sub.) -k.sub.(λ.sbsb.2.sub.).a.sub.λ.sbsb.1 which can eliminate the influence of the coexisting ingredient, is produced from the absorbance signal C.sub.(λ.sbsb.2.sub.) and the product signal k.sub.(λ.sbsb.2.sub.).C.sub.λ.sbsb.1. A signal ΔS=a.sub.(λ.sbsb.2.sub.) /k.sub.(λ.sbsb.2.sub.) -a.sub.λ.sbsb.1 which indicates the difference-absorbance spectrum of the ingredient to be analyzed, is produced from the signals ΔDS and k.sub.(λ.sbsb.2.sub.).

Claims

1. A method of analyzing one ingredient in a mixed solution with two light beams of different wavelengths comprising:

a first step of passing a first light beam having a wavelength fixed at a predetermined value and a second light beam which is scanned over a range of wavelengths, selectively through a solvent to obtain first and second photometric signals corresponding to said first and second light beams passed through said solvent, respectively;

a second step of producing first and second reference signals from said first and second photometric signals, respectively;

a third step of passing said first and second light beams through a first solution containing only a first ingredient in said solvent to obtain third and fourth photometric signals corresponding to said first and second light beams passed through said first solution respectively, said first ingredient being one of the ingredients contained in said mixed solution;

a fourth step of obtaining a first normalized signal by normalizing said third photometric signal by said first reference signal and a second normalized signal by normalizing said fourth photometric signal by said second reference signal;

a fifth step of producing a signal indicating a ratio of said second normalized signal to said first normalized signal;

a sixth step of passing said first and second light beams through said mixed solution to obtain fifth and sixth photometric signals corresponding to said first and second light beams passed through said mixed solution, respectively;

a seventh step of obtaining a third normalized signal by normalizing said fifth photometric signal by said first reference signal and a fourth normalized signal by normalizing said sixth photometric signal by said second reference signal;

an eighth step of producing a signal indicating a product of said third normalized signal and the ratio indicating signal produced in the fifth step; and

a ninth step of producing a signal indicating a difference between said signal produced in the eighth step and said fourth normalized signal.

2. A method according to claim 1 further comprising a tenth step of producing a signal indicating a ratio of the difference indicating signal produced in said ninth step to the ratio indicating signal produced in said fifth step.

5. A method according to claim 1 or 2, wherein said first and second reference signals are produced in said second step to that absorbances corresponding to said first and second photometric signals resulting from said first and second light beams having passed through said solvent are substantially equal to zero at the respective wavelengths of the second light beam.

3. A method of analyzing one ingredient in a mixed solution with two light beams of different wavelengths comprising:

a first step of passing a first light beam having a wavelength fixed at a predetermined value and a second light beam which is scanned over a range of wavelengths, selectively through a solvent to obtain first and second photometric signals corresponding to said first and second light beams passed through said solvent, respectively;

a second step of producing first and second reference signals from said first and second photometric signals, respectively;

a third step of passing said first and second light beams through a first solution containing only a first ingredient in said solvent to obtain third and fourth photometric signals corresponding to said first and second light beams passed through said first solution respectively, said first ingredient being one of the ingredients contained in said mixed solution;

a fourth step of obtaining a first normalized signal by normalizing said third photometric signal by said first reference signal and a second normalized signal by normalizing said fourth photometric signal by said second reference signal;

a fifth step of producing a signal indicating a ratio of said second normalized signal to said first normalized signal;

a sixth step of passing said first and second light beams through said mixed solution to obtain fifth and sixth photometric signals corresponding to said first and second light beams passed through said mixed solution, respectively;

a seventh step of obtaining a third normalized signal by normalizing said fifth photometric signal by said first reference signal and a fourth normalized signal by normalizing said sixth photometric signal by said second reference signal;

an eighth step of producing a signal indicating a ratio of said fourth normalized signal and said ratio indicating signal produced in the fifth step; and

a ninth step of producing a difference indicating signal indicating a difference between the ratio signal produced in said eighth step and said third normalized signal.

4. A method according to claim 3, wherein said first and second reference signals are produced in said second step so that absorbances corresponding to said first and second photometric signals resulting from said first and second light beams having passed through said solvent are substantially equal to zero at the respective wavelengths of the second light beam.

6. A device for analyzing one ingredient in a mixed solution with two light beams of different wavelengths comprising:

first means for passing a first light beam having a wavelength fixed at a predetermined value and a second light beam which is scanned over a range of wavelengths through a mixed solution containing a first ingredient the absorbance spectrum of which is known and at least one additional ingredient to be analyzed to obtain first and second photometric signals corresponding to the first and second light beams;

second means for producing a ratio indicating signal indicating a ratio of a fourth photometric signal obtained by passing said second light beam through a first solution containing only the first ingredient to a third photometric signal obtained by passing said first light beam through said first solution;

third means for producing a further signal indicating the product of said first photometric signal and said ratio indicating signal; and

fourth means for producing a difference indicating signal indicating a difference between said second photometric signal and said further signal.

7. A device according to claim 6 wherein said second means includes means for holding photometric signals resulting from said first and second light beams having passed through a solvent as reference signals respectively, and means for producing a signal indicating a ratio of each of said first and second photometric signals resulting from said first and second light beams having passed through said mixed solution to a corresponding one of said reference signals.

8. A device according to claim 6 further comprising fifth means for producing a signal indicating the ratio of the difference indicating signal produced in said fourth means to the ratio indicating signal produced in said second means.

9. A method of analyzing one ingredient in a mixed solution with two light beams of different wavelengths comprising:

a first step of passing a first light beam having a wavelength fixed at a predetermined value and a second light beam which is scanned over a range of wavelengths through a mixed solution containing a first ingredient, the absorbance spectrum of which is known, to obtain first and second photometric signals corresponding to the first and second light beams passed through the mixed solution, respectively;

a second step of producing a ratio indicating signal indicating a ratio of a fourth photometric signal obtained by passing said second light beam through a second solution containing only the first ingredient to a third photometric signal obtained by passing said first light beam through said second solution;

a third step of producing a further signal indicating the product of said first photometric signal and said ratio indicating signal; and

a fourth step of producing a difference indicating signal indicating a difference between said second photometric signal and said further signal derived from said first photometric signal and said ratio indicating signal.

10. A method according to claim 9 further comprising a fifth step of producing a signal indicating a ratio of the difference indicating signal produced in said fourth step to the ratio indicating signal produced in said second step.

11. A device for analyzing one ingredient in a mixed solution with two light beams of different wavelengths comprising:

a first means for passing a first light beam having a wavelength fixed at a predetermined value and a second light beam which is scanned over a range of wavelengths selectively through a solvent to obtain first and second photometric signals corresponding to the first and second light beams passed through the solvent, respectively;

a second means for producing first and second reference signals from the first and second photometric signals respectively;

a third means for producing third and fourth photometric signals by passing the first and second light beams through a solution containing only a first ingredient, the absorbance spectrum of which is known, instead of the solvent;

a fourth means for producing a first normalized signal by normalizing the third photometric signal by the first reference signal and a second normalized signal by normalizing the fourth photometric signal by the second reference signal;

a fifth means for producing a signal indicating a ratio of the second normalized signal to the first normalized signal;

a sixth means for storing the first and second reference signals and the ratio indicating signal;

a seventh means for producing fifth and sixth photometric signals by passing the first and second light beams through the mixed solution containing the first ingredient and ingredient to be analyzed, instead of the solution,

an eighth means for producing a third normalized signal by normalizing the fifth photometric signal by the first reference signal and a fourth normalized signal by normalizing the sixth photometric signal by the second reference signal;

a ninth means for producing a signal indicating a product of the third normalized signal and the ratio indicating signal produced in said fifth means; and

a tenth means for producing a signal indicating a difference between the signal produced in said ninth means and the fourth normalized signal.

12. A device according to claim 11 further comprising an eleventh means for producing a signal indicating a ratio of the difference indicating signal produced in said tenth means to the ratio indicating signal produced in said fifth means.