Accession Number : AD0660557

Title :   AN IMPROVED ELECTROCHEMICAL CARBON DIOXIDE SENSOR.

Descriptive Note : Rept. for Jun 66-Feb 67,

Corporate Author : SCHOOL OF AEROSPACE MEDICINE BROOKS AFB TEX

Personal Author(s) : Reyes,Robert J. ; Martin,Charles F. ; Neville,J. Ryan

Report Date : JUL 1967

Pagination or Media Count : 18

Abstract : Continued work with an electrochemical carbon dioxide detector has produced a unit that has improved signal stability as well as a considerably shortened response time. The detector configuration incorporates a pH electrode and an Ag-AgCl reference electrode joined by an electrolyte solution composed of tris(hydroxymethyl)aminomethane buffer and including the enzyme carbonic anhydrase as a catalyst. The various factors affecting the response time were investigated and CO2 tension measurements were obtained with a bare glass electrode. Increased electrical stability, as well as simplification of the electronics, was achieved by the incorporation of a field-effect transistor (FET) in the probe assembly of the detector. The conventional high impedance electrometer system normally used with such detectors was replaced and capacitive pickup problems at the input stage of remotely placed signal conditioners were minimized by close physical arrangement of the FET and the detector. Response times of less than 2 seconds for 98% of a step change (14 to 35 mm. Hg PCO2) were obtained. (Author)

Descriptors :   (*CARBON DIOXIDE, DETECTORS), GAS DETECTORS, BLOOD CHEMISTRY, CHEMICAL ANALYSIS, ELECTROCHEMISTRY, ELECTRODES, STABILITY, FIELD EFFECT TRANSISTORS, LABORATORY EQUIPMENT, BLOOD ANALYSIS

Subject Categories : Biochemistry
      Medical Facilities, Equipment and Supplies

Distribution Statement : APPROVED FOR PUBLIC RELEASE