Accession Number:



Development of N2 Sensor for In vivo Measurement of PN2 in Biological Tissues

Descriptive Note:

Final rept. 1 Aug 1988-31 Oct 1991,

Corporate Author:


Report Date:


Pagination or Media Count:



An electrochemical sensor for nitrogen was developed based on the kinetics of the reaction of a transition metal cation, ruthenium II aquopentaammine, with molecular dinitrogen. Prototype PN2 sensors were fabricated which incorporate an array of carbon microdisks as the active electrode surface with the smallest probe diameter equivalent to a 23 gauge hypodermic needle. Sensors were characterized on the basis of their electrochemical responses for a diffusion controlled process, the kinetics of the Ru II-N2 complexation reaction, and their operating performance in measuring PN2. In vitro performance tests under equilibrium conditions demonstrated a linear response over a PN2 range of 1 to 10 atm. Iterative PN2 measurements had a 5 reproducibility with equilibrium PN2 of 0.77 or 1 atm. Under dynamic conditions of changing PN2, the sensor response indicated that the actual concentration of dissolved N2 equilibrates slowly with changes in N2 pressure in the gas phase above the solution, with washout occurring more slowly than washing. Electroanalytical protocols which were satisfactory for early prototypes based on large glassy carbon electrodes must be modified for use with the microdisk array sensors due to the different mass transport properties of microelectrode arrays. Development of standard protocols and a user interface would enhance the utility of the sensor technology to the hyperbaric medical research community. Nitrogen sensor, Nitrogen electrode, PN2 measurement, Nitrogen tension, Microelectrodes, Electrode array, Electrochemical sensor, Nafion, Dinitrogen complex, Ruthenium-dinitrogen complex.

Subject Categories:

  • Biology
  • Electrical and Electronic Equipment

Distribution Statement: