ELECTROSPRAY-IONIZATION TIME-OF-FLIGHT MASS-SPECTROMETER FOR ELEMENTAL ANALYSIS

Electrospray ionization (ESI) has been combined with a time-of-flight (TOF) mass spectrometer for elemental analysis. With the use of a heat ed-capillary interface, the instrument is shown to be stable to within 5% relative standard deviation (RSD) over a 60-min period. The ratio between the isotopes of rubidium is measured with a precision of 0.4% RSD for a 1-min integration time. With the addition of a supporting el ectrolyte as a spray stabilizer and internal standard, the dynamic ran ge is linear over at least three orders of magnitude. The extent of so lvent-cluster fragmentation is found to be governed primarily by the v oltage differential between the capillary and skimmer and, to a lesser extent, by the capillary temperature. The capillary voltage also affe cts the distribution of species among the parent and its fragment ions for ferrocene and tetraethyllead. Under ''mild'' interface conditions , a resolving power of 1400 is achieved for an organolead complex. A s pectrum for a larger molecule, polypropylene glycol, is presented to s how the versatility of the ESI-TOF instrument for both atomic and mole cular analysis.