Thermo Finnigan LLC

Michael L Poltash

Eloy R Wouters

Joshua A Silveira

Wei Wei

Gary A Schultz

Brandon Howard Robson

David E Minkler

Dale Lindseth

Packed-tip electrospray ionization (ESI) emitters for mass spectrometry are described. In one aspect an ESI emitter stores a first type of particle. A liquid chromatography (LC) column is coupled with the emitter via a junction. The LC column stores a different type of particle than the ESI emitter to facilitate better chromatographic and ESI performance.

Packed tip electrospray emitter

An electrospray ionization system used in mass spectrometry provides for improved current measurement. The system includes a fluid union, a fluid column coupled with a first port of the fluid union, a power source coupled with the fluid union and configured to apply a voltage potential to the fluid union, and an electrospray emitter coupled with a second port of the fluid union. The power source is coupled with the first port and configured to apply the voltage potential to the first port to restrict current leakage from the fluid union. The current sensing circuit is configured to determine an electrical current flow between the power source and the at least one of the fluid union and the first port.

Electrospray current measurement in the nanospray and microspray regime

A method for cleaning an electrospray emitter of a mass spectrometer comprises the steps of: (a) changing a mode of operation of the electrospray emitter from a stable jet mode of operation to a dripping mode or a pulsating mode of operation by lowering a magnitude, |V|, of a voltage applied between a counter electrode and the electrospray emitter; and (b) changing the mode of operation of the electrospray emitter from the dripping mode or the pulsating mode of operation to the stable jet mode of operation by increasing the magnitude, |V|, of the applied voltage; wherein the repetitions are performed at a predetermined frequency that depends on one or more of liquid flow rate, an emitter internal diameter, and liquid properties.

Method and apparatus for improved electrospray emitter lifetime

A method for cleaning a first electrospray emitter of a mass spectrometer comprises: changing an operating mode of the first electrospray emitter from a stable jet mode of operation to a dripping or pulsating mode of operation by lowering a magnitude of a voltage applied between a counter electrode and the first electrospray emitter, |V|; moving the first electrospray emitter from a first emitter position from which electrospray ions are delivered to a mass spectrometer inlet to a second emitter position and, simultaneously, moving a second electrospray emitter from a third emitter position to a fourth emitter position; causing a cleaning solvent to flow through the first electrospray emitter at least until a droplet of the cleaning solvent forms on an exterior surface of the first electrospray emitter while operating the electrospray emitter in the dripping mode of operation; and causing the droplet to dislodge from the emitter exterior.

A method for cleaning an electrospray emitter of a mass spectrometer, comprises: (a) changing a mode of operation of the electrospray emitter from a stable jet mode of operation to a dripping mode or a pulsating mode of operation by lowering a magnitude of a voltage applied between an counter electrode and the electrospray emitter; (b) causing a cleaning solvent to flow through the electrospray emitter at least until a droplet of the cleaning solvent forms on an exterior surface of the electrospray emitter while operating the electrospray emitter in the dripping mode of operation; and (c) causing the droplet to dislodge from the electrospray emitter exterior.

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Fremont, CA, United States of America

Michael L Poltash