Application： 1,9-Diaminononane is used as an organic intermediate. It is also used to detect spermine and spermidine by matrix-assisted laser desorption/ionization combined with time-of-flight mass spectrometry ( MALDI-TOF MS) in foods and for the identification of apoptosis-related proteins by nano-flow ultra-performance liquid chromatography tandem mass-spectrometry (UPLC-MS/MS) after treatment with spermine and spermidine.