▎ 摘　　要

NOVELTY - An alkene detection gas sensor (100) comprises a reaction section (110) comprising a palladium catalyst and oxidizes an alkene in a sample gas to convert the oxidized alkene into an aldehyde and/or a ketone, a reaction section (120) containing hydroxylamine salts and reacts with aldehyde and/or ketone converted in the reaction section (110) to generate an acid, and a response section (130) including an electrode supporting a semiconductor material whose electrical resistance value changes depending on the generated acid. The palladium catalyst, the hydroxylamine salts, and the semiconductor material are separated from each other. USE - Gas sensor used in system for detecting alkene e.g. ethylene in sample gas (all claimed), used as raw material for synthesizing chemical substances e.g. polyethylene and ethanol. ADVANTAGE - The gas sensor can stably detects the alkene in the sample gas. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for an alkene detection system, which comprises the alkene detection gas sensor that detects an alkene in a sample gas and a detection unit detects a change in the electric resistance value from the alkene detection gas sensor. DESCRIPTION OF DRAWING(S) - The drawing shows a block diagram of the alkene detection gas sensor. Sensor (100) Reaction section (110,120) Response section (130)