A new time-of-flight mass spectrometer has been developed that uses an electrospray source and an inductively coupled plasma to extract molecular, atomic, and isotopic information simultaneously from a single sample. This paper will focus on characterization of the ESI channel. Sensitivities are reported for hexadecyltrimethylammonium, tetrahexylammonium, tetraoctylammonium, myoglobin, insulin, cyanocobalamin, leucine enkephalin, and alcohol dehydrogenase. Skimmer-nozzle collisionally induced dissociation is explored for adduct removal and analyte fragmentation on the ESI channel for tetraoctylammonium ion and leucine enkephalin. Long-term and short-term spray stability is also examined.