Development of ion attachment mass spectrometry and its applications

Ion Attachment Mass Spectrometry (IAMS) that can measure labile organic compounds without any fragmentation is reviewed. The ionization without fragmentation can be performed because a neutral molecule becomes an adduct ion by the attachment of Li+ with a small amount of energy of less than 2 eV by the Coulomb force. A third-body gas, such as 100 Pa N-2, removes any excess energy of the adduct ion and makes it stable. Almost all organic compounds, except for simple structure ones, have a minimum detection amount of about 1 v/v ppb, 10(-16) mol/s and linear response ranges of 6 figures. Because of "direct" (without GC) introduce contributed by fragment-free, IAMS can find heat-sensitive impurities, grasp thermal decomposition/desorption components, monitor exhaust gas from vehicles or process gases in industrial plants, and detect free-radical in plasma. It is difficult for conventional El (electron ionization) to distinguish homologues due to the same fragment patterns. By contrast, we detected each molecular ion and some impurities in several kinds of phthalates with JAMS. Although acetal has not only similar fragment patterns of the compounds by El, but also no molecular ion by CI, we could clearly measure it by IAMS. Molecular ion of a organometallic complex Cu (hfac) (tmvs), which has low binding energy of less than I eV, appeared in JAMS. A newly developed apparatus of IAMS for low-pressure sampling, small flow rate and high-speed response was suitable for measuring the vacuum process and thermal analysis, and for connecting to GG Improving the present weak points, such as the detection limit, machine size and decreasing of sensitivities by moisture might lead to a evolution: realizing GC-IAMS for correct identification, "direct & real-time GC/MS" without GC and pretreatment, field measurements by a hand-carrier, and the measurement of unstable compounds in a flame/ explosion/ atmospheric environment.