High-performance liquid chromatography combined with electron ionization mass spectrometry: A review

The present review illustrates the state of the art in the field of liquid chromatography (LC) hyphenated to electron ionization mass spectrometry (EI MS). An overview of applications over the last decades is given, in order to demonstrate the benefits arisen from the use of EI for the characterization of typically LC-amenable samples. Key advantages are related to the extensive fragmentation pattern useful for structure elucidation and the absence of matrix effects, differently from the most commonly employed LC-MS interfaces (e.g., electrospray). Different interfaces which made the LC-EI MS coupling feasible are described, along with several approaches proposed to overcome well-known incompatibility issues.