Device for delivery of multiple liquid sample streams to a mass spectrometer

Abstract

An electrospray apparatus employing multiple electrospray needles mounted in a circular arrangement sequentially delivers multiple sample streams to a mass spectrometer for analysis. One electrospray device includes an electrospray chamber, a rotatable needle supporting plate, a plurality of electrospray needles mounted on the plate, and a charger for applying a charge to droplets delivered to the electrospray chamber by the needles. Another electrospray device includes an electrospray chamber, a plurality of electrospray needles arranged in a circular arrangement, a charger, and a rotatable member for delivering gas phase ions from one needle at a time to the mass spectrometer. The rotatable electrospray apparatus provides fast repetitive analysis of simultaneously operating chromatography columns or other sample streams with a single mass spectrometer.

What is claimed is:  
     
         1 . An electrospray device for a mass spectrometer comprising: 
 a plurality of electrospray needles mounted on a support in a substantially circular arrangement, the electrospray needles connectable to a plurality of sample streams for delivery of droplets of the sample streams to a mass spectrometer orifice;    a rotatable member for directing droplets of one of the sample streams at a time to the mass spectrometer orifice; and    a charger for applying a charge to the droplets of the sample stream and causing ions to be focused into a beam passing through the mass spectrometer orifice.    
     
     
         2 . The electrospray device according to  claim 1 , wherein the needles are mounted on a rotatable needle support.  
     
     
         3 . The electrospray device according to  claim 2 , wherein the rotatable needle support is a rotatable disk having the plurality of electrospray needles mounted such that axes of the needles are substantially parallel.  
     
     
         4 . The electrospray device according to  claim 2 , wherein the rotatable needle support is a rotatable disk having the plurality of electrospray needles mounted with axes of the needles arranged radially.  
     
     
         5 . The electrospray device according to  claim 1 , wherein the plurality of electrospray needles are coaxial needles having an inner lumen for delivery of the sample streams and an outer lumen for delivery of a nebulizer gas.  
     
     
         6 . The electrospray device according to  claim 1 , wherein the plurality of electrospray needles are single lumen needles for delivery of the sample streams.  
     
     
         7 . The electrospray device according to  claim 1 , wherein the charger comprises a charged sampling plate positioned within an electrospray chamber substantially surrounding the mass spectrometer orifice and grounded electrospray needles.  
     
     
         8 . The electrospray device according to  claim 1 , wherein the charger comprises an electrical contact for electrically charging the electrospray needles by connection to a voltage source, and a biased sampling plate.  
     
     
         9 . The electrospray device according to  claim 1 , further comprising a plurality of chromatography columns mounted on the support, wherein each of the chromatography columns is in fluid connection with one of the electrospray needles for delivery of the sample streams exiting the chromatography columns to the mass spectrometer.  
     
     
         10 . The electrospray device according to  claim 1 , further comprising a plurality of chromatography columns connected to the electrospray needles by fluid connection lines.  
     
     
         11 . The electrospray device according to  claim 1 , wherein the electrospray needles are surrounded by an electrospray chamber housing for containment of the needles.  
     
     
         12 . The electrospray device according to  claim 1 , further comprising a motor for rotation of the rotatable member and a controller for controlling the rotation of the rotatable member to achieve a consistent dwell time for each of the electrospray needles.  
     
     
         13 . The electrospray device according to  claim 2 , wherein a controller rotates the needle support in a first direction to analyze the sample streams from approximately one half of the electrospray needles and rotates the needle support in a second direction to analyze the sample streams from a remaining approximately one half of the electrospray needles.  
     
     
         14 . The electrospray device according to  claim 1 , wherein the rotatable member is a rotatable blocking member having an opening which allows droplets from one of the sample streams at a time to be delivered to the mass spectrometer orifice.  
     
     
         15 . The electrospray device according to  claim 14 , wherein the rotatable blocking member is a rotatable cylinder having an axis of rotation substantially aligned with the mass spectrometer orifice.  
     
     
         16 . The electrospray device according to  claim 14 , wherein the plurality of electrospray needles are mounted in fixed positions on the support and the rotatable blocking member is positioned between the plurality of electrospray needles.  
     
     
         17 . A method of delivering a plurality of sample streams to a mass spectrometer for sequential analysis, the method comprising: 
 providing a plurality of sample streams to a plurality of electrospray needles mounted on a support plate;    continuously spraying the sample streams with the electrospray needles; and    sequentially providing an outlet of each of the electrospray needles at a delivery position for a predetermined dwell time by rotating and stopping a rotatable member to deliver the sample streams to the mass spectrometer.    
     
     
         18 . The method according to  claim 17 , wherein the predetermined dwell time is less than about 0.5 seconds.  
     
     
         19 . The method according to  claim 17 , wherein the rotatable member is rotated in a first direction to sequentially deliver a plurality of sample streams to the mass spectrometer and the plate is then rotated in a second direction.  
     
     
         20 . The method according to  claim 17 , wherein the electrospray needles which are not at the delivery position deliver the sample streams to a collection tray.  
     
     
         21 . The method according to  claim 17 , wherein the step of sequentially providing an outlet at a delivery position is performed by rotating the support for the needles.  
     
     
         22 . The method according to  claim 17 , wherein the step of sequentially providing an outlet at a delivery position is performed by maintaining the needles stationary and rotating the rotatable member in the form of a blocking member with an opening.