METHOD AND APPARATUS TO DESOLVATE IONS AT HIGH PRESSURE AND TO IMPROVE TRANSMISSION AND CONTAMINATION IN THE COUPLING OF MASS SPECTROMETERS AND MOBILITY SPECTROMETERS WITH IONIZERS

摘要

A method and apparatus that operate at near atmospheric pressure are described to simultaneously (i) desolvate the droplets produced by an ions source (including electrospray sources), to (ii) separate the surviving droplets from the analyte ions, to (iii) increase the transmission of ions through the inlet of an analyzer, while (iv) preventing the passage through said inlet of neutral contaminants and low mobility species and droplets that could potentially impair the operation of the analyzer, which include mass spectrometers and ion mobility spectrometers. In the present invention, contaminant low mobility species are efficiently deflected away from the analyzer inlet by a sweep flow. The sweep flow is laminar, affects ions in a region immediately after they leave the ionizer, and provides a preliminary separation of species. Consequently, the dilution effect produced by coulombic repulsion is minimized, and thus, analyte ions pass through the analyzer inlet with a higher transmission.

主权项

1. A system to minimize contamination resulting from a flow of ions transmitted from an ionization source to an analyzer, said ionization source producing charged particles of interest and other low mobility charged particles, including charged droplets, and neutral species within the flow of ions that could contaminate the analyzer if introduced therein, the system comprising:
an inlet electrode and an outlet electrode spaced apart to define a desolvation and separation region, wherein said inlet electrode separates said desolvation and separation region from said ionization source, and communicates said ion source with said desolvation and desolvation region through an inlet slit, and wherein said outlet electrode separates said desolvation and separation region from said analyzer, and communicates said desolvation and separation region with said analyzer through an outlet slit; a source of clean gas, which provides a continuous flow of sweep gas; a heating stage for heating said continuous flow of sweep gas, to a temperature higher than the boiling point of said charged droplets; a laminarizing stage, configured to minimize turbulence in said continuous flow of sweep gas; a voltage source, which provides a voltage that creates an electric field between said inlet electrode and said outlet electrode, such that said ions are directed form said inlet slit towards said outlet slit; and a sweep flow outlet, wherein said continuous flow of sweep gas, after passing through said heating and laminarizing stages, is directed towards said sweep flow outlet, said continuous flow of sweep gas passing across said desolvation and separation region, such that any said charged droplets within the flow of ions are at least partially evaporated by said continuous flow of sweep gas and such that said charged droplets which cannot be completely evaporated, said low mobility charged particles, and said neutral species are swept by said continuous flow of sweep gas to said sweep flow outlet so as to limit entry thereof into said analyzer; and wherein such electric field being configured so that ions resulting from said partially evaporated droplets are also directed towards the outlet slit.