IN RECENT years, mass spectrometry (MS) has become one of the most important analytical techniques in biochemical analytics. The development of soft ionisation techniques and the improvement in instrumentation led to a reliable and ``easy-to-use'' technique, which is now used in most biochemical laboratories. However, the main application for MS techniques is still the static analysis of molecules, e.g. proteins or nucleic acids. Despite early attempts in the 1980s by RICHARD CAPRIOLI[10], there are only a few approaches using the special capabilities of MS to investigate enzymatic reactions[21].