Tetrahydrothiophene additives are added to natural gas, which is a chemical compound, which will not be oxidized in the air, is a very stable gas with chemical properties, and the volatility is also very low, it will emit a smell that is not easy to emit off, this gas is not corrosive to gas equipment and transportation pipelines, when gas leakage occurs, people's sense of smell will be felt in time, and there will be no cough and headache, the portable natural gas analyzer developed by Shanghai Puyi adopts the ultraviolet principle, It can easily detect the content of tetrahydrothiophene in natural gas.