Surface effects in fast atom bombardment mass spectrometry of ethylene glycol-glycerol mixtures

Binary mixtures of ethylene glycols HO(CH₂CH₂O)_xH (x = 3–5) with glycerol were investigated by fast atom bombardment mass Spectrometry. The relative intensities in the ethylene glycol partial mass spectra as a function of concentration exhibit a steep slope in the low concentration range. With increasing concentration the curves asymptotically approach the 100% line. This effect increases from triethylene to pentaethylene glycol. Comparison of these results with those of surface tension measurements leads to the conclusion that the high sensitivity of fast atom bombardment mass Spectrometry for ethylene glycols is caused by the surface-active properties of these compounds, which lead to an enrichment of the surface investigated with the substance molecules.