The ion/molecule reactions of low-mass compounds in the ion trap MS, such as alcohol, ether, amine, aldehyde, ketone and so on, were studied. The reaction characters and disciplinarians were summarized, which were described as self-chemical ionization (SCI) reactions. The products of the ion/molecule reactions of butanone and propenol were determined by FTMS, And the accurate masses of the product ions of butanone and propenol resulting from the ion/molecule reactions were obtained, The SCI spectra were compared with the standard EI spectra (NIST98) , and the database of the SCI-MS was established. Therefore the identifications of these species of low-mass compounds on the ion trap MS can be made more accurate.

Key words: ION TRAPS, MASS SPECTROGRAPHY, BUTANONE, PROPENOL, QUALITATIVE ANALYSIS