SIZE-EXCLUSION CHROMATOGRAPHY WITH ELECTROSPRAY MASS-SPECTROMETRIC DETECTION

We interfaced a size-exclusion chromatograph (SEC) to a mass spectrometer operating in the electrospray mode of ionization. Stable electrospray conditions were obtained using a tetrahydrofuran mobile phase containing similar to 10(-5) M dissolved sodium salt, which affords pseudomolecular ions through cationization. Using the SEC with electrospray detection, we calibrated the SEC for an ethylene-oxide-based nonionic surfactant. The calibration standards were the surfactant oligomers themselves. The chemical composition distribution of acrylic macromonomers was profiled across the molecular weight distribution. A nonuniform chemical composition distribution was observed. Cross-linkers, additives and stabilizers, and coalescing solvents contained in a complex waterborne coating formulation were analyzed in a single experiment.