Biological gas sensor

A biological gas sensor comprising:

• a sensor which has in the sensitive part thereof a bicarbonate buffer solution held by a first gas permeable membrane and detects a carbon dioxide partial pressure based on the hydrogen ion concentration of the bicarbonate buffer solution;
• a liquid holding part which has in the inside thereof the sensitive part of said sensor and at least a part of the inner wall of said holding part is made of a second gas permeable membrane;
• and
• an aqueous solution which is held in said liquid holding part, is substantially isotonic with said bicarbonate buffer solution, and contains a metallic ion or a metallic compound capable of reacting with hydrogen sulfide.

A biological gas sensor comprising:

• a sensor which has in the sensitive part thereof a bicarbonate buffer solution held by a first gas permeable membrane and detects a carbon dioxide partial pressure based on the hydrogen ion concentration of the bicarbonate buffer solution;
• a liquid holding part which has in the inside thereof the sensitive part of said sensor and at least a part of the inner wall of said holding part is made of a second gas permeable membrane containing powder of a metal or a compound thereof capable of reacting with hydrogen sulfide;
• and
• an aqueous solution which is contained in said liquid holding part and is substantially isotonic with said bicarbonate buffer solution.

A biological gas sensor comprising:

• a sensor which has in the sensitive part thereof a bicarbonate buffer solution held by a first gas permeable membrane and detects a carbon dioxide partial pressure based on the hydrogen ion concentration of the bicarbonate buffer solution;
• a liquid holding part which has in the inside thereof the sensitive part of said sensor and at least a part of the inner wall of said holding part is made of a second gas permeable membrane;
• and
• an aqueous alkaline solution which is contained in said liquid holding part and is substantially isotonic with said bicarbonate buffer solution.