THERMALLY ASSISTED ELECTROSPRAY INTERFACE FOR LIQUID-CHROMATOGRAPHY MASS-SPECTROMETRY

An electrospray interface for liquid chromatography/mass spectrometry (LC/MS) is described that combines the direct heating of high-performance liquid chromatography (HPLC) effluent that is characteristic of thermospray-type interfaces. This interface is called the thermally assisted electrospray interface for LC/MS. The device can accept the total effluent from a liquid chromatograph at flow rates ranging up to 500 muL/min. The HPLC effluent is nebulized into charged droplets by a combination of heat and an applied electric field. Ions emitted from charged droplets are mass-analyzed by a triple quadrupole mass spectrometer equipped with an atmospheric pressure ion sampling orifice. Singly or multiply charged ions, indicating the molecular weight of a sample, are observed with minimal fragmentation. The extent of multiple charging observed in electrospray and ion spray mass spectrometry is decreased somewhat in thermally assisted electrospray. Labile compounds which undergo thermal decomposition by conventional thermospray show no decomposition with thermally assisted electrospray.