DEVELOPMENT OF A MEDICAL FIBEROPTIC PH SENSOR BASED ON OPTICAL-ABSORPTION

A new fiber-optic pH sensor system has been developed. The sensor uses an absorbtive indicator compound with a long wavelength absorbtion peak near 625 nm; change in absorbtion over the pH range 6.8 to 7.8 is reasonably linear. The sensor is interrogated by a pulsed, red LED. Return light signal is...

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Bibliographic Details
Published in:IEEE transactions on biomedical engineering 1992-05, Vol.39 (5), p.531-537
Main Authors: WOLTHUIS, R, MCCRAE, D, SAASKI, E, HARTL, J, MITCHELL, G
Format: Article
Language:English
Subjects:
Engineering
Engineering, Biomedical
Science & Technology
Technology
Online Access:Get full text
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Summary:A new fiber-optic pH sensor system has been developed. The sensor uses an absorbtive indicator compound with a long wavelength absorbtion peak near 625 nm; change in absorbtion over the pH range 6.8 to 7.8 is reasonably linear. The sensor is interrogated by a pulsed, red LED. Return light signal is split into short and long wavelength components with a dichroic mirror; the respective signals are detected by photodiodes, and their photocurrents are used to form a ratiometric output signal. In laboratory tests, the sensor system provided resolution of 0.01 pH, accuracy of +/- 0.01 pH, and response time of 30-40 s. Following gamma sterilization, laboratory sensor testing with heparinized human blood yielded excellent agreement (e.g., r = 0.992 for n = 42) with a clinical blood gas analyzer. Excellent sensor performance and low cost, solid-state instrumentation are hallmarks of this sensor-system design.
ISSN:0018-9294
DOI:10.1109/10.135548