Near-infrared noninvasive spectroscopic determination of pH

Patent · 11 August 1998

OSTI ID:871767

Alam, Mary K ^[1]; Robinson, Mark R ^[2]

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1. P.O. Box 1083, Cedar Crest, NM 87008
2. 1415 Calle del Ranchero NE, Albuquerque, NM 87106

Methods and apparatus for, preferably, determining noninvasively and in vitro pH in a human. The non-invasive method includes the steps of: generating light at three or more different wavelengths in the range of 1000 nm to 2500 nm; irradiating blood containing tissue; measuring the intensities of the wavelengths emerging from the blood containing tissue to obtain a set of at least three spectral intensities v. wavelengths; and determining the unknown values of pH. The determination of pH is made by using measured intensities at wavelengths that exhibit change in absorbance due to histidine titration. Histidine absorbance changes are due to titration by hydrogen ions. The determination of the unknown pH values is performed by at least one multivariate algorithm using two or more variables and at least one calibration model. The determined pH values are within the physiological ranges observed in blood containing tissue. The apparatus includes a tissue positioning device, a source, at least one detector, electronics, a microprocessor, memory, and apparatus for indicating the determined values.

• Research Organization: Sandia National Laboratories (SNL), Albuquerque, NM, and Livermore, CA
• Assignee: Alam, Mary K. (P.O. Box 1083, Cedar Crest, NM 87008);Robinson, Mark R. (1415 Calle del Ranchero NE, Albuquerque, NM 87106)
• Patent Number(s): US 5792050
• Application Number: 08/615,762
• OSTI ID: 871767
• Country of Publication: United States
• Language: English

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