DESIGN AND PERFORMANCE OF AN IN-LINE SURFACE-INDUCED DISSOCIATION DEVICE IN A 4-SECTOR MASS-SPECTROMETER

A new in-line surface-induced dissociation device has been designed and characterized in a high performance four-sector tandem mass spectrometer. The design incorporates a target electrode parallel to the ion beam axis and an angled deflector plate (45 degrees relative to the ion beam) to provide large collision angles. In addition, an extraction electrode (parallel to the target electrode) is employed to efficiently extract product ions from the target surface. Results obtained with this device indicate high internal energy deposition (up to 16.3 eV) as measured with the thermometer ions W(CO)(6)(+.) and Si(C2H5)(4)(+.), as evidenced by extensive dissociation of the refractory pyrene molecular ion, and as indicated by the b(3)/y(2) ratio in the product ion spectrum of leucine enkephalin. High resolution provided by the four-sector instrument for both precursor ions and product ions allows the observation of previously unobserved dissociation products in the surface-induced dissociation spectra of Si(C2H5)(4)(+.) and novel ion-surface reaction products in spectra of W(CO)(6)(+.) ions after collisions with hydrocarbon-covered surfaces. Both hydrogen atom and hydrocarbon abstraction products are observed. The dissociation efficiencies measured with the in-line device are approximately 1% when hydrocarbon-coated surfaces are used and increase fivefold with a fluorinated surface.