RESUMO
A device to produce low temperature plasma ( LTP) was designed and constructed to serve as the ion source of a high resolution mass spectrometry, and was applied to qualitatively analyze the steroid samples. In comparison with conventional electrospray ionization mass spectrometry, low temperature plasma mass spectrometry ( LTP-MS) had some advantages such as simple sample pretreatment and less interference. Mass spectrometry and tandem mass spectrometry were used to characterize the steroid samples in this research, and it was found that the structural stability of each steroid sample was presented in its mass spectrum, while in the tandem mass spectra there were more fragments of H2 O lost. And then the fragmentation process of typical steroid samples in collision induced dissociation ( CID ) was discussed based on theoretical calculation. In addition, by comparing tandem mass spectrometry and the fragmentation process, a pair of isomers of testosterone and dehydroepiandrosterone could be distinguished successfully.