Direct Determination of Nonionic Surfactants in Spiked Tap Water by Desorption Chemical Ionization and Tandem Mass Spectrometry

A mass spectrometric method employing desorption chemical ionization has been set up to analyze nonionic surfactant mixtures. Mass spectra of standard solutions provide an extremely accurate measure of molecular weight distributions. The method is sufficiently sensitive to work with detection limits placed in the low ppm range for the study of distribution and in the ppb range for single oligomers. Higher sensitivity is achieved when methanol solutions are analyzed rather than tap water solutions. A detailed investigation of the chemical structure of single components in a mixture is made possible by collisionally activating the fragmentation of selected molecular ions in a tandem mass spectrometric experiment.