A Conductive Polymeric Material Used for Nanospray Needle and Low-Flow Sheathless Electrospray Ionization Applications

A conductive polypropylene/graphite mixture is used for the production of polymeric nanospray needle emitters and as a coating on fused-silica capillaries that are used for sheathless electrospray ionization (ESI). The described production of these polymeric nanospray needle emitters and sheathless ESI contacts is exceptionally easy and at a very low cost. The described polymeric nanospray emitters have shown excellent features regarding their chemical inertness and spray performance. The long-term stability of the nanospray needles exceeds 24 h of continuous use. Furthermore, the resistance to electrical discharges, which is one of the factors that often limits the lifetime of metal coated tips, has proven to be outstanding. A voltage of up to 5 kV could be applied without loss of spray performance. The use of polypropylene emitters offers a number of desirable features, as compared to silica based emitters. Among these features are mechanical flexibility and simplified regeneration of the nanospray need...