Method and apparatus for measuring pH of medium solution
First Claim
1. A pH measuring method comprising:
- illuminating a medium solution with a plurality of light beams,the medium solution including;
a first material which, in a wavelength region of 300 nm to 800 nm, has a first absorption peak; and
a second material which, in the wavelength region of 300 nm to 800 nm, has a second absorption peak or a second convergence point where an absorbance is converged irrespective of a pH, and a third absorption peak or a third convergence point where an absorbance is converged irrespective of a pH,the plurality of light beams including;
a first light beam, a wavelength of which corresponds to the first absorption peak;
a second light beam, a wavelength of which corresponds to the second absorption peak or the second convergence point;
a third light beam, a wavelength of which corresponds to the third absorption peak or the third convergence point; and
a fourth light beam, a wavelength of the fourth light beam at which an absorbance of at least one of the first material and the second material is converged irrespective of a pH;
receiving transmitted or reflected light beams of the first to fourth light beams;
measuring absorbances at the wavelengths of the received transmitted or reflected light beams of the first to fourth light beams respectively; and
calculating a pH of the medium solution based on the measured absorbances,wherein the pH of the medium solution is calculated with an expression including a sum of the absorbance of the first material with the absorbance of the second material.
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Abstract
A pH measuring method includes: illuminating a medium solution, which includes: a first material; and a second material, with a plurality of light beams, which includes: a first light beam, a wavelength of which corresponds to a first absorption peak; a second light beam, a wavelength of which corresponds to a second absorption peak or a second convergence point; a third light beam, a wavelength of which corresponds to a third absorption peak or a third convergence point; and a fourth light beam, a wavelength of the fourth light beam at which an absorbance of at least one of the first and second materials is converged irrespective of a pH; receiving transmitted or reflected light beams of the first to fourth light beams; measuring absorbances at the wavelengths of the received light beams respectively; and calculating a pH of the medium solution based on the absorbances.
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Citations
11 Claims
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1. A pH measuring method comprising:
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illuminating a medium solution with a plurality of light beams, the medium solution including; a first material which, in a wavelength region of 300 nm to 800 nm, has a first absorption peak; and a second material which, in the wavelength region of 300 nm to 800 nm, has a second absorption peak or a second convergence point where an absorbance is converged irrespective of a pH, and a third absorption peak or a third convergence point where an absorbance is converged irrespective of a pH, the plurality of light beams including; a first light beam, a wavelength of which corresponds to the first absorption peak; a second light beam, a wavelength of which corresponds to the second absorption peak or the second convergence point; a third light beam, a wavelength of which corresponds to the third absorption peak or the third convergence point; and a fourth light beam, a wavelength of the fourth light beam at which an absorbance of at least one of the first material and the second material is converged irrespective of a pH; receiving transmitted or reflected light beams of the first to fourth light beams; measuring absorbances at the wavelengths of the received transmitted or reflected light beams of the first to fourth light beams respectively; and calculating a pH of the medium solution based on the measured absorbances, wherein the pH of the medium solution is calculated with an expression including a sum of the absorbance of the first material with the absorbance of the second material. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A pH measuring apparatus comprising:
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a light emitting section configured to emit a plurality of light beams, the plurality of light beams including; a first light beam, a wavelength of which corresponds to a first absorption peak; a second light beam, a wavelength of which corresponds to a second absorption peak or a second convergence point where an absorbance is converged irrespective of a pH; a third light beam, a wavelength of which corresponds to a third absorption peak or a third convergence point where an absorbance is converged irrespective of a pH; and a fourth light beam, a wavelength of the fourth light beam at which an absorbance of at least one of a first material and a second material is converged irrespective of a pH; a light receiving section configured to measure absorbances of the wavelengths of the first to fourth light beams respectively; and a calculating section configured to calculate a pH from values of the absorbances, wherein the pH of the medium solution is calculated with an expression including a sum of the absorbance of the first material with the absorbance of the second material.
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11. A pH measuring method comprising:
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illuminating a medium solution with a plurality of light beams, the medium solution including; a first material which, in a wavelength region of 300 nm to 800 nm, has a first absorption peak; and a second material which, in the wavelength region of 300 nm to 800 nm, has a second absorption peak or a second convergence point where an absorbance is converged irrespective of a pH, and a third absorption peak or a third convergence point where an absorbance is converged irrespective of a pH, the plurality of light beams including; a first light beam, a wavelength of which corresponds to the first absorption peak; a second light beam, a wavelength of which corresponds to the second absorption peak or the second convergence point; a third light beam, a wavelength of which corresponds to the third absorption peak or the third convergence point; and a fourth light beam, a wavelength of the fourth light beam at which an absorbance of at least one of the first material and the second material is converged irrespective of a pH; receiving transmitted or reflected light beams of the first to fourth light beams; measuring absorbances at the wavelengths of the received transmitted or reflected light beams of the first to fourth light beams respectively; and calculating a pH of the medium solution based on the measured absorbances, wherein the pH of the medium solution is calculated with correction using multiple regression analysis in which a logarithm of an absorbance ratio calculated from the measured absorbances is employed, and wherein the multiple regression analysis is performed by a regression expression indicated by following expression;
pH=B0+B1*Φ
λ
y/λ
j
Φ
λ
i/λ
j=log(Aλ
i/Aλ
j)
pH=B0+B1*Φ
λ
1/λ
4+B2*Φ
λ
2/λ
4+B1*Φ
λ
3/λ
4.
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Specification