Rapid communications in mass spectrometry vol:9 issue:15 pages:1499-1501
Addition of carbon or graphite powder, to either the matrix or the sample if no matrix is used, facilitates the formation of sample ions. For most of the compounds investigated, [M+H](+) ions are observed. For Long-chain alcohols, [M-1](+) ions are formed. This new analysis method allows mass spectra of compounds, that hitherto were difficult or impossible to ionize, using liquid secondary mass spectrometry to be obtained and enhances the signal intensity of poorly ionizable compounds. Using this technique in the negative ion mode, a spectrum of Fomblin(R) can be obtained which is suitable for calibration purpose over a mass range of 1400 u. The observed effect is possibly due to enhancement of the field strength at the sample surface in the presence of carbon powder. No evidence of contamination of the ion source was visible after four weeks of intensive use of this technique.