Nicotine: Nicotine is one of the active compositions of tobacco. It is a substance with extensive applications. Its chemical name is 3-(1-Methyl-2-pyrrolidinyl) pyridine. According to the different position of the N-methyl-tetrachloropyrrole on the pyridine cycle, nicotine can be divided into three types, that is, ŚÁ-nicotine, ŚÂ-nicotine, and Y- nicotine. In tobacco, there is mainly the ŚÂtype.