Abstract: The present paper describes carbon-dioxide and ammonia gas-sensing probes containing neutral carriers based inner pHelectrodes.Octadecyl nicotinate (ODN), Hexadecyl nicotinate (HDN), dioctyloctadecylamine (DOODA), and dimethyloctadecylamine (DMODA), were used as neutral carries for preparation of electrodes with graphite inner contacts forming flat solvent polymeric membrane (SPM) pHsensitive tips.The results obtained show that the potentiometric response characteristics of the gas-sensing probes depend on the nature of the carriers.Carbon dioxide gas-sensing probe with ODNand ammonia gas-sensing probe with DOODAas neutral carries of the inner pHelectrodes have fair potentiometric response characteristics.Acorn navel tissue based pyruvate decarboxylase was prepared using the carbon-dioxide probe as primary electrode.The response characteristics such as electrode slope of the enzyme probe prepared was better than those of the glass inner electrode counterparts.

Key words: Carbon dioxide gas-sensing probe, Ammonia gas-sensing probe, Neutral carrier