Determination of pH including hemoglobin correction
First Claim
1. A method of determining the pH of a sample, comprising:
- a) Determining an infrared spectrum of the sample;
b) Determining the concentration of hemoglobin of the sample;
c) Selecting a model relating an infrared spectrum to pH that is applicable for samples having the determined hemoglobin concentration;
d) Determining the pH of the sample from the infrared spectrum and the selected model.
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Accused Products
Abstract
Methods and apparatuses of determining the pH of a sample. A method can comprise determining an infrared spectrum of the sample, and determining the hemoglobin concentration of the sample. The hemoglobin concentration and the infrared spectrum can then be used to determine the pH of the sample. In some embodiments, the hemoglobin concentration can be used to select an model relating infrared spectra to pH that is applicable at the determined hemoglobin concentration. In other embodiments, a model relating hemoglobin concentration and infrared spectra to pH can be used. An apparatus according to the present invention can comprise an illumination system, adapted to supply radiation to a sample; a collection system, adapted to collect radiation expressed from the sample responsive to the incident radiation; and an analysis system, adapted to relate information about the incident radiation, the expressed radiation, and the hemoglobin concentration of the sample to pH.
70 Citations
25 Claims
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1. A method of determining the pH of a sample, comprising:
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a) Determining an infrared spectrum of the sample;
b) Determining the concentration of hemoglobin of the sample;
c) Selecting a model relating an infrared spectrum to pH that is applicable for samples having the determined hemoglobin concentration;
d) Determining the pH of the sample from the infrared spectrum and the selected model. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of determining the pH of a sample, comprising:
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a) Determining an infrared spectrum of the sample;
b) Determining the concentration of hemoglobin of the sample;
c) Selecting a model relating an infrared spectrum to pH that is applicable for samples having the determined hemoglobin concentration;
d) Determining the pH of the sample from the infrared spectrum and the selected model;
wherein determining an infrared spectrum comprises measuring the sample absorbance of infrared radiation in the spectral frequency range from 4000-11000 cm−
1. - View Dependent Claims (11, 12)
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13. A method of determining pH of a sample, comprising:
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a) Determining an infrared spectrum of the sample;
b) Verifying that the spectrum is spectrally consistent with a model relating an infrared spectrum and associated hemoglobin concentration to pH;
c) Determining the concentration of hemoglobin, hematocrit, or equivalent of the sample;
d) Determining the pH of the sample from the infrared spectrum, the determined hemoglobin, hematocrit, or equivalent concentration, and the model. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21)
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22. A method of determining pH of a sample, comprising:
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a) Determining an infrared spectrum of the sample;
b) Verifying that the spectrum is spectrally consistent with a model relating an infrared spectrum and associated hemoglobin concentration to pH;
c) Determining the concentration of hemoglobin, hematocrit, or equivalent of the sample;
d) Determining the pH of the sample from the infrared spectrum, the determined hemoglobin, hematocrit, or equivalent concentration, and the model;
wherein determining an infrared spectrum comprises measuring the sample absorbance of infrared radiation in the spectral frequency range from 4000-11000 cm−
1. - View Dependent Claims (23, 24)
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25. An apparatus for determining the pH of a sample, comprising:
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a) An illumination system adapted to direct radiation to the sample;
b) A collection system adapted to receive radiation expressed from the sample responsive to incident radiation;
c) An analysis system, relating two or more of radiation expressed, incident radiation, and hemoglobin concentration to sample pH;
wherein;
d) The infrared radiation encompasses the spectral frequency range between 4000-25000 cm−
1;
e) Infrared radiation is delivered to the sample through at least one of;
optical fibers, light guides, and imaging optics;
f) Hemoglobin concentration is determined using radiation in the spectral frequency range from 10,000-25,000 cm−
1; and
g) pH is determined using radiation in the spectral frequency range from 4,000-10,000 cm−
1 combined with the hemoglobin concentration.
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Specification