Highly sensitive potentiometric measuring method for measurement of free H2S in physiologic samples

- Air-gap type H2S sensor has been developed with LOD of submicromolar range.
- Enhanced sensitivity was obtained using [Ag(CN)2]− containing measuring film.
- Application of sensor to physiologic samples.
- Difference in H2S level could be detected between inflamed and healthy tissues.

Hydrogen sulfide in high concentration is a well-known toxic gaseous molecule; nevertheless, H2S is synthetized in mammalls' body in small concentration participating important physiological processes. It also is implicated in inflammation as a mediator molecule. In this work, a potentiometric air gap cell has been developed in order to apply it in the quantitative study of the H2S accompanied the inflammatory disease in animal experiments. The cell was tested using aqueous standard sample solutions and super-Nernstian response has been obtained in the concentration range of interest and submicromolar lower detection limit, respectively. Animal experiments have been carried out in healthy and inflamed paws of sacrificed mice. The measurements showed significant difference in the H2S level of the control and carrageenan treated tissues of the experimental animals.