Production and Characterization of Beams of Polystyrene Ions

Abstract

The formation of gaseous polystyrene molecular ions [M]⁺ by means of the technique of field desorption is proposed to involve creation of a charged sample/gas interface and subsequent field evaporation of ions. The molecular ions so formed fragment spontaneously in the gas phase, provided the emitter temperature is sufficiently high. The polystyrene chains rupture near their ends rather than in their centres, which is proposed to be a consequence of efficient charge delocalization. Following collisional activation, the polystyrene chains break up to give low-mass fragment ions. The low-mass fragment ions are proposed to be the result of successive depolymerization steps, following initial direct bond cleavage within the polymer chain.