Electrospray Ionization Efficiency Scale of Organic Compounds (Talk at 14th Nordic MS Conference)

Mass spectrometer (MS) with electrospray ionization (ESI) coulpled to a liquid chromatograph (LC) has during the recent decade become the most widespread analysis method of analysis for a vast number of microconstituents and contaminants (pesticides, mycotoxins, drug residues, etc) in a large diversity of samples (food, feed, blood, environmental samples, etc). A key component of the system is the electrospray ion source, which converts the molecules (or ions) in the liquid phase to gas-phase ions. The mechanism of electrospray ionization is complex and although the ESI technique is widely used, its mechanism is still not fully understood. An important feature of ESI is that not all molecules are readily ionized by ESI. The general principles and features of molecular structure governing the efficiency of ESI ionization are known, but there is still a long way to go until the full understanding of the process is gained.
Chair of Analytical Chemistry of University of Tartu is strongly involved in unraveling the mystery of ESI ionization mechanism. As a tool for this an extensive scale of ionization efficiencies containing 62 compounds with ionization efficiencies ranging by a factor of about 1 000 000 has been compiled and is further supplemented by adding more compounds.
This scale was presented at the 14th Nordic MS Conference. The full presentation can be downloaded from here.
Article about this ESI ionization efficiency scale has also been published in the journal Analytical Chemistry.