Liquid injection field desorption ionization: a new tool for soft ionization of samples including air-sensitive catalysts and non-polar hydrocarbons

Mass analysis of air-sensitive samples, like organometallic catalysts, require inert sample preparation to avoid degradation of such reactive molecules. Non-polar samples like hydrocarbons are stable but, nonetheless, need soft ionization to reduce congestion of fragment peaks for analysis of complex mixtures. This paper describes a novel type of probe that combines the advantages of field ionization and field desorption (FI/FD) with an efficient liquid inlet. The new method is called liquid injection field desorption ionization (LIFDI). Sample solutions are delivered to the emitter wire inside the ion source without breaking the vacuum. Sample preparation is reduced to dipping the LIFDI transfer capillary into another sample vial. In the case of air-sensitive samples kept under inert gas, the preparation is inert without special experimental effort. The new tool provides significantly raised sample throughput at excellent sensitivity.