The DART source was operated with helium in positiveion mode. The gas heater was set to 475° C. Resins were cured in an oven for several hours before analysis; some resin samples had been cured for longer periods of time (months or years). Exact masses and accurate isotopic abundances were used to assign elemental compositions for peaks in the mass spectra. Nominalmass spectra were exported into a library database in NIST format to facilitate identification of unknowns. Figure 2.