Mass Spectrometry of Polymers: Polypropylene Glycol

Mass spectra have been measured, using the field desorption technique, for polypropylene glycols with nominal mass-average relative molecular masses of 1000, 2000, 3000 and 4000. Ions of up to m/z 7400 have been observed. Major peaks in the spectra correspond to (M + H)⁺ ions. (M + Na)⁺ ions are observed if sodium iodide is added to the sample. There are strong peaks corresponding to fragmentation of the polymer chains close to their termini. It is suggested that these fragmentations are induced by the strong electric fields at the emitter.